<PAGE>   1

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                    U.S. SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                      ------------------------------------
                                   FORM 10-K

                 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                  FOR THE FISCAL YEAR ENDED DECEMBER 31, 1999
                         COMMISSION FILE NUMBER 1-10351

                      ------------------------------------

                    POTASH CORPORATION OF SASKATCHEWAN INC.
           (Exact name of the registrant as specified in its charter)

<TABLE>
<S>                                            <C>
                 SASKATCHEWAN                                       N/A
       (State or other jurisdiction of                        (I.R.S. employer
        incorporation or organization)                      identification no.)
</TABLE>

                             122 - 1ST AVENUE SOUTH
                    SASKATOON, SASKATCHEWAN, CANADA S7K 7G3
                                  306-933-8500
 (Address and telephone number of the registrant's principal executive offices)

          SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

<TABLE>
<S>                                            <C>
             TITLE OF EACH CLASS                    NAME OF EXCHANGE ON WHICH REGISTERED
         Common Shares, No Par Value                      New York Stock Exchange
(Including rights under the Shareholder Rights
                  Agreement)
</TABLE>

        SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: NONE

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.  Yes [X]  No

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of the registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K.  [X]

     At March 15, 2000, the registrant had 53,041,972 Common Shares outstanding,
and the aggregate market value of the 52,969,028 Common Shares held by
non-affiliates of the registrant was approximately $2,413,401,351.

                      DOCUMENTS INCORPORATED BY REFERENCE

     Portions of the registrant's Annual Report to Shareholders for the fiscal
year ended December 31, 1999 (the "1999 Annual Report") are incorporated by
reference into Part II.

     Portions of the registrant's Proxy Circular for its Annual Meeting of
Shareholders to be held on May 11, 2000 (the "2000 Proxy Circular") are
incorporated by reference into Part III.
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<PAGE>   2

                                     PART I

ITEMS 1 AND 2.  BUSINESS AND PROPERTIES.

GENERAL

     Potash Corporation of Saskatchewan Inc. ("PCS") and its direct and indirect
subsidiaries (together with PCS' predecessors, the "Company") is one of the
world's largest integrated fertilizer and related industrial and feed products
companies. In 1999, the Company's potash production represented an estimated 15%
of global potash production. In 1999, the Company had 24% of global potash
capacity and an estimated 60% of global excess potash capacity, giving it more
available potash capacity than any single company or country other than Canada.
The Company is the third largest producer of phosphates worldwide by capacity,
currently representing approximately 7% of world phosphoric acid production and
7% of world phosphoric acid capacity. The Company is currently the largest
nitrogen producer in the Western Hemisphere.

     PCS is incorporated under the laws of the Province of Saskatchewan and is
the successor to a corporation without share capital established by the Province
of Saskatchewan in 1975. Between 1976 and 1990, the Company acquired substantial
interests in the Saskatchewan potash industry. It purchased the Cory mine in
1976, the Rocanville and Lanigan mines in 1977, and, by 1990, 100% of the Allan
mine when the Company acquired all of the outstanding shares of Saskterra
Fertilizers Ltd. In addition, in 1978 the Company acquired reserves at
Esterhazy, which are mined by a third party.

     In November 1989, the Company was privatized by the Province of
Saskatchewan. While the Province initially retained an ownership interest in the
Company, this interest had been reduced to zero by the end of 1993. In October
1993, the Company acquired from Rio Algom Limited ("Rio") its New Brunswick
potash mine and port facilities and its Patience Lake mine in Saskatchewan (the
"Rio Acquisition").

     In April 1995, the Company purchased all of the outstanding shares of
Texasgulf Inc. ("Texasgulf") from Elf Aquitaine, Inc. ("Elf (USA)") and Williams
Acquisition Holding Company, Inc. ("Williams"). At the time of the acquisition,
the name "Texasgulf Inc." was changed to PCS Phosphate Company, Inc. ("PCS
Phosphate"). PCS Phosphate manufactures and sells solid and liquid phosphate
fertilizers, animal feed supplements, and purified phosphoric acid which is used
in food products and industrial processes. Its facility in Aurora, North
Carolina is the largest vertically-integrated phosphate mine and processing
plant in the world. Other assets of PCS Phosphate include: animal feed plants in
three states; two industrial phosphoric acid plants owned through the joint
venture carrying on business as PCS Purified Phosphates, formerly Albright &
Wilson Company; an undivided 50% interest in an ammonia storage terminal in
Savannah, Georgia; and PCS Phosphate's product distribution infrastructure.

     In October 1995, the Company purchased all of the outstanding shares of
White Springs Agricultural Chemicals, Inc. ("White Springs") from Occidental
Chemical Corporation ("OxyChem"). White Springs' primary assets are a phosphate
mine and two chemical plant complexes in northern Florida, Swift Creek and
Suwannee River. Other assets of White Springs include an animal feed plant in
Davenport, Iowa, two additional animal feed plants at the Suwannee River
facility, and the remaining undivided 50% interest in the ammonia storage
terminal in Savannah, Georgia owned with PCS Phosphate.

     In March 1997, the Company through its subsidiary PCS Nitrogen, Inc. ("PCS
Nitrogen") acquired all of the outstanding shares of Arcadian Corporation
("Arcadian"). PCS Nitrogen produces nitrogen fertilizers and nitrogen chemicals
at facilities in Georgia, Louisiana, Ohio and Tennessee in the United States,
and has large scale operations in Trinidad. Other assets of PCS Nitrogen include
a 50% interest in a joint venture that owns and operates an ammonia storage
terminal near Houston, Texas and a 50% joint venture interest in a carbon
dioxide processing operation at PCS Nitrogen's plant in Augusta, Georgia.

     In December 1998, the Company purchased, pursuant to a public offering by
the State of Israel, 108,359,925 Ordinary Shares of Israel Chemicals Ltd.
("ICL") for approximately $92 million. This purchase represented 9.03% of the
issued and outstanding Ordinary Shares of ICL. ICL, through its subsidiaries, is
a potash, phosphate and bromine producer and is also involved in other specialty
chemical products.

                                       I-1
<PAGE>   3

     In July 1999, the Company purchased all of the outstanding shares of Minera
Yolanda SCM, a Chilean sodium nitrate and potassium nitrate producer for
approximately $37 million. At the time of the acquisition, the name was changed
to PCS Yumbes SCM ("PCS Yumbes"). See "Potash Operations - Properties".

     In February 2000, the Company sold its shares in Moab Salt, Inc. to
Intrepid Oil & Gas, LLC. The primary asset of Moab Salt, Inc. is a solution
potash and salt mine in Moab, Utah.

     On March 23, 2000, the Company completed a transaction with Rhodia Inc. to
acquire the remaining 50% ownership interest in the merchant grade phosphoric
acid joint venture company formerly called Albright & Wilson Company for
approximately $42 million. Upon closing of the transaction, the joint venture
company was renamed PCS Purified Phosphates. The Company and Albright & Wilson
Americas Inc. had been operating the business as a 50/50 partnership. With the
completion of the transaction, the Company now owns 100% of the purified acid
plant and blending plant in Aurora, North Carolina and 100% of the blending
plant in Cincinnati, Ohio. Rhodia Inc. retained a polyphosphoric acid production
unit in Charleston, South Carolina.

     PCS has its head office and executive offices at Suite 500, 122 - 1st
Avenue South, Saskatoon, Saskatchewan, Canada S7K 7G3. In this Form 10-K, the
term "Company" means PCS, its predecessors and its direct and indirect
subsidiaries unless the context otherwise indicates.

     The Company has three principal business segments: potash, phosphate and
nitrogen. For information with respect to the net sales revenue, operating
income and assets attributable to each segment and to the Company's domestic and
international sales, see Note 18 to the Company's audited consolidated financial
statements as at December 31, 1999 and 1998 and for each of the three years
ended December 31, 1999 (together with the Notes thereto, the "Consolidated
Financial Statements"), incorporated by reference under Item 8.

     The Company presents its financial statements in accordance with accounting
principles generally accepted in Canada ("Canadian GAAP"). See Note 32 to the
Consolidated Financial Statements for a discussion of certain significant
differences between Canadian GAAP and accounting principles generally accepted
in the United States as they relate to the Company.

     Unless otherwise specified, dollar amounts are stated in U.S. Dollars.

     Except for the historical statements and discussions contained herein,
statements contained in this report on Form 10-K constitute "forward looking
statements" within the meaning of Section 27A of the U.S. Securities Act of 1933
and Section 21E of the U.S. Securities Exchange Act of 1934. Forward looking
statements may include words such as "expect", "estimate", "project",
"anticipate", "should", "intend" and similar expressions or variations on such
expressions. Any filing of the Company with the U.S. Securities and Exchange
Commission may include forward looking statements. In addition, other written or
oral statements which constitute forward looking statements have been made and
may in the future be made by or on behalf of the Company, including statements
concerning future operating and financial performance, the Company's share of
new and existing markets, general industry trends and the Company's performance
relative thereto and the Company's expectations as to requirements for capital
expenditures and environmental matters.

     These forward looking statements rely on a number of assumptions concerning
future events and are subject to a number of uncertainties and other factors,
many of which are outside the Company's control, that could cause actual results
to differ materially from such statements. These factors include, but are not
limited to, fluctuations in supply and demand in fertilizer, sulfur and
petrochemical markets, changes in competitive pressures, including pricing
pressures, potential higher actual costs incurred in connection with
restructuring charges as compared to costs estimated for the purposes of
calculating such charges, uncertainty and variations in future undiscounted net
cash flows from use together with residual values estimated for purposes of
calculating restructuring charges, changes in capital markets, changes in
currency and exchange rates, unexpected geological and environmental conditions,
imprecision in reserve estimates, the outcome of legal proceedings and changes
in government policy and regulation, including environmental regulation.

                                       I-2
<PAGE>   4

     The Company disclaims any obligation to update or revise any forward
looking statements, whether as a result of new information, future events or
otherwise.

POTASH OPERATIONS

     The Company's potash operations include the mining and production of
potash, which is predominantly used as fertilizer.

PROPERTIES

     The Company controls the right to mine 615,400 acres of land in
Saskatchewan. Included in these holdings are mineral rights to 507,000 acres
contained in blocks around the six mines in which the Company has an interest,
of which acres approximately 36% are owned by the Company, approximately 50% are
under lease from the Province of Saskatchewan and approximately 14% are leased
from other parties. The majority of the leases are for 21-year terms, renewable
at the Company's option. The Company's remaining 108,400 acres are located
elsewhere in Saskatchewan.

     Potash is mined by the Company from two main potash bearing formations in
Saskatchewan: the Patience Lake member of the prairie evaporites in the north
and the Esterhazy member of the prairie evaporites in the south. The Patience
Lake member is mined at the Lanigan, Allan, Patience Lake and Cory mines, and
the Esterhazy member is mined at the Rocanville and Esterhazy mines.

     Under a long-term mining and processing agreement (the "Mining and
Processing Agreement") effective through 2026, International Minerals & Chemical
(Canada) Limited Partnership ("IMC") mines and processes PCS reserves at the
Esterhazy mine. PCS has the option to terminate this agreement every five years.
It did not opt to give notice to terminate in December 1995. IMC has the option
of abandoning the mine at any time after 2011, thus terminating the Mining and
Processing Agreement. In 1998, the Mining and Processing Agreement was amended
to provide for the operation of the agreement on a calendar year basis as
opposed to a fiscal year ending June 30. In each year the maximum the Company is
permitted to take under the Mining and Processing Agreement is 952,500 tonnes
and the minimum required amount is 453,600 tonnes. For the year ending December
31, 2000, the Company has notified IMC that it requires 725,700 tonnes of
finished product.

     Water inflow at the Esterhazy mine has continued, to a greater or lesser
degree, since December 1985. Substantial pumping capacity has been installed and
remedial efforts have been undertaken. The Company's share of water inflow
remediation costs for 1999 was $6.9 million. IMC has stated that it will
continue conventional mining. PCS has no indication from IMC that solution
mining or substitute shafts will be pursued at this time.

     Potash is also produced by the Company at its New Brunswick mine from the
flank of an elongated salt structure. Granular product is also produced by the
Company at its Cassidy Lake, New Brunswick facility using standard grade product
from certain of the Company's other mine sites.

     PCS Yumbes, acquired in 1999, holds mining concessions on certain sodium
nitrate reserves in the Atacama desert in northern Chile. The production
facility is in the development stage and has been designed to produce 300,000
tonnes of sodium nitrate per year at full production. Production is expected to
begin in 2000. Sodium nitrate is combined with potassium chloride to produce
potassium nitrate, primarily used for intensely cultivated and chloride
sensitive crops.

PRODUCTION

     The Company produces potash using both conventional and solution mining
methods. In conventional operations, shafts are sunk to the ore body and mining
machines cut out the ore, which is lifted to the surface for processing. In
solution mining, the potash is dissolved in a warm brine and pumped to the
surface for processing.

     In 1999, the Company's conventional potash operations mined 16.80 million
tonnes of ore at an average grade of 23.1% K(2)O. In 1999 the Company's potash
produced consisted of 6.39 million tonnes of potash (KCl) with an average grade
of 60.98% K(2)O, representing approximately 43% of North American production.

                                       I-3
<PAGE>   5

     The Company's present annual potash production capacity is approximately
12.2 million tonnes KCl, which includes maximum annual production under the
Mining and Processing Agreement with IMC of approximately one million tonnes at
Esterhazy. In 1999, the Company's production capacity represented approximately
55% of the North American total while its excess capacity was an estimated 80%
of North American excess production capacity. The Company allocates production
among its mines on the basis of various factors, including the grades of product
which can be produced and cost efficiency. The Patience Lake mine, which was
originally a conventional underground mine, now employs a solution mining
method, while the other Saskatchewan mines which the Company owns or in which it
has an interest employ conventional underground mining methods.

     The New Brunswick mine is a conventional cut and fill mine, while the Moab,
Utah mine, which was sold in February 2000, employs a solution mining method. In
addition to their potash production, these mines also produced .81 million
tonnes of sodium chloride (salt) in 1999.

     As part of the Rio Acquisition, the Company granted a royalty interest to
Rio based upon production and revenue from the New Brunswick and Patience Lake
potash mines and mills (the "Royalty"). The terms of the Royalty provide that if
production meets specified base production levels or the sales of potash are at
prices which meet specified base sales prices, a royalty per tonne is to be
paid, calculated on a formula basis. Payments under the Royalty are limited to a
term expiring October 7, 2003 and to a maximum aggregate payment of Cdn$50
million. No payments have been made in respect of the Royalty to date.

RESERVES

     The Company estimates that its conventional mines in Saskatchewan contained
4.76 billion tonnes of recoverable ore at an average grade of 22.9% K(2)O as at
December 31, 1999, and that such ore will yield 1.5 billion tonnes of finished
product (KCl) at an average grade of 60% K(2)O.

     The Company's ore reserve estimates for its conventional mining operations
in Saskatchewan are based on exploration drill hole data, seismic data and
actual mining results during the past 25 years. The Company's estimated
recoverable ore and the estimated volumes of finished product from such ore are
as follows:

<TABLE>
<CAPTION>
                                                  RECOVERABLE    FINISHED
MINE                                                  ORE        PRODUCT
----                                              -----------    --------
                                                   (MILLIONS OF TONNES)
<S>                                               <C>            <C>
Allan...........................................    1,390.9        447.9
Cory............................................    1,050.3        350.7
Esterhazy.......................................       76.8         24.4
Lanigan.........................................    1,554.8        501.8
Rocanville......................................      683.0        217.5
                                                    -------      -------
  Total.........................................    4,755.8      1,542.3
                                                    =======      =======
</TABLE>

     The Company believes that, with production rates at full capacity and
utilizing current technology, each of the Allan, Cory and Lanigan mines has a
reserve life in excess of 100 years, the Rocanville mine has a reserve life in
excess of 90 years, and that the Esterhazy mine has a reserve life of at least
20 years.

     Given the characteristics of the solution mining method employed at the
Patience Lake mine, it is not possible to estimate definitively the productive
capacity of or the recoverable ore from this operation. However, based on
information obtained upon the acquisition of the mine, current technology and
the present mining area for this operation, the Company believes that the mine
has a reserve life of at least 40 years for the existing mine workings.
Different techniques will have to be utilized to mine reserves outside of the
existing mine workings.

     Based on geophysics, exploration drill hole data, definition drilling
underground and actual mining results, the Company estimates proven reserves of
48.0 million tonnes of recoverable ore and 16.6 million tonnes of estimated
finished product (KCl) at its New Brunswick mine. The Company believes that,
based upon its proven reserves, the New Brunswick mine has a reserve life of at
least 21 years with production at full

                                       I-4
<PAGE>   6

capacity. The Company estimates that probable reserves at the New Brunswick mine
consist of 200 million tonnes of recoverable ore and 72 million tonnes of
estimated finished product (KCl). The Company believes that, based upon its
proven and probable reserves, the New Brunswick mine has a reserve life in
excess of 100 years at full production capacity and utilizing current
technology.

PHOSPHATE OPERATIONS

     The Company mines phosphate ore and manufactures solid and liquid
fertilizers, animal feed supplements and purified phosphoric acid which is used
in food products and industrial processes.

PROPERTIES

     The Company conducts its phosphate operations primarily at two facilities,
one a 35,000-acre facility near Aurora, North Carolina (the "Aurora Facility")
and the other a 96,000-acre facility near White Springs in northern Florida (the
"White Springs Facility"). The Company believes the Aurora Facility to be the
largest integrated phosphate mine and phosphate processing complex at one site
in the world. The Aurora Facility, having an annual P(2)O(5) capacity of 1.2
million tonnes, includes a six million tonne per-year mining operation, four
sulfuric acid plants, four phosphoric acid plants, a liquid fertilizer (11-37-0)
plant, a superphosphoric acid plant, two diammonium phosphate ("DAP") plants and
a solid fertilizer plant capable of producing DAP, granular triple
superphosphate ("GTSP") or monoammonium phosphate ("MAP"). The Company also
holds all outstanding interests in PCS Purified Phosphates (formerly Albright &
Wilson Company) which produces high purity phosphoric acid at Aurora. The White
Springs Facility is the third largest P(2)O(5) producer, by capacity, in the
United States, with an annual capacity of 1.1 million tonnes. The White Springs
Facility includes a mine and two production facilities, Suwannee River and Swift
Creek, with two sulfuric acid plants, three phosphoric acid plants, two DAP
plants, a superphosphoric acid plant, a dicalcium phosphate plant and a
deflourinated phosphate rock plant located at the Suwannee River complex and two
sulfuric acid plants and a phosphoric acid plant located at the Swift Creek
complex. The Company's other properties include animal feed plants in Davenport,
Iowa; Kinston, North Carolina; Marseilles, Illinois; and Weeping Water,
Nebraska, and bulk terminal facilities at Morehead City, North Carolina.

     At its Geismar, Louisiana facility ("Geismar Facility"), acquired as part
of the Arcadian acquisition, the Company manufactures a variety of phosphate
products that are used for agricultural and industrial purposes. The Geismar
Facility has a sulfuric acid plant, a phosphoric acid plant, a superphosphoric
acid plant, and a liquid fertilizer (11-37-0) plant. A significant portion of
the phosphoric acid produced at the Geismar Facility is sold as feedstock to
Rhodia, Inc. for use in its neighboring purified acid plant.

PRODUCTION

     The Company extracts phosphate ore using surface mining techniques. At each
mine site, the ore is mixed with recycled water to form a slurry, which is
pumped from the mine site to the Company's processing facilities. The ore is
then screened to remove coarse materials, washed to remove clay and floated to
remove sand to produce phosphate "rock". The annual production capacity of the
Company's mines is currently 9.6 million tonnes of phosphate rock. During 1999,
the Aurora Facility's total production of phosphate rock was 4.4 million tonnes
and the White Springs Facility's total production of phosphate rock was 3.6
million tonnes. The Company generally operates its phosphate mine and phosphate
processing plants 24 hours a day, seven days a week, using rotating shifts. The
sequence for mining portions of the Aurora property has been identified in the
permit issued by the U.S. Army Corps of Engineers in 1997. For the near term,
the Company expects to be mining in an area of non-optimal mining conditions.
The quality and condition of the ore is relatively inferior to ore previously
mined at the Aurora Facility. This, combined with the general configuration of
the area, does not allow efficient use of the Company's mining equipment and
technology. Beginning in late 2000, the Company expects to enter areas believed
to hold ore superior in thickness and quality, located closer to the Company's
chemical plants, and configured so as to generally allow efficient use of
Company mining equipment and technology.

                                       I-5
<PAGE>   7

     Phosphate rock is the major input in the Company's phosphorus processing
operations. In addition to phosphate ore, the principal raw materials required
by the Company are sulfur, sulfuric acid and ammonia. The production of
phosphoric acid requires substantial quantities of sulfur, which the Company
purchases from third parties. In December 1997, the Company entered into a
ten-year supply contract with an offshore supplier to supply a portion of the
Company's sulfur requirements and also committed to build a multipurpose
ocean-going vessel to ship such sulfur as well as handle sulfuric acid,
phosphoric acid and other chemicals. The Company produces sulfuric acid at the
Aurora Facility, White Springs Facility and Geismar Facility and purchases
additional sulfuric acid from unaffiliated sellers. The Company also transports
surplus production of sulfuric acid at the White Springs Facility to the Aurora
Facility as needed. Sulfur and sulfuric acid have been in abundant supply in
recent years. However, in 1998, the remaining U.S. Frasch sulfur producer
announced the closure of one of its two mines, an action which reduced readily
available U.S. supplies of sulfur and increased prices, notwithstanding a world
market having excess supplies of sulfur. While sulfur prices rose during the
first quarter of 1999, prices declined during the second half of 1999.

     The Company purchases all of its ammonia from or through PCS Nitrogen and
PCS Sales (USA), Inc., wholly owned subsidiaries of the Company. The Company
reacts phosphoric acid with ammonia to produce DAP and MAP, as well as liquid
fertilizers. In addition, ammonia operations include the purchase, sale and
terminalling of anhydrous ammonia. Most of the ammonia that is currently
purchased by PCS Nitrogen is produced in Russia and imported through a Company
operated ammonia terminal located within the port of Savannah (Garden City,
Georgia).

     Substantially all of the phosphate rock produced by the Company is used
internally for the production of phosphoric acid, superphosphoric acid ("SPA"),
chemical fertilizers, purified phosphoric acid and animal feed products.

     A portion of the Company's phosphoric acid production, merchant grade
phosphoric acid ("MGA"), is sold in liquid form, mostly to foreign and domestic
producers of solid fertilizers. The solid fertilizers produced by the Company
are DAP and, to a lesser extent, GTSP and MAP. Over one-half of the Company's
DAP is exported, with the balance sold domestically, mostly to large regional
dealers that custom blend solid fertilizers.

     The Company's liquid fertilizer products, 74% of which were sold
domestically, consist principally of low-magnesium SPA, which the Company
markets under the name "LoMag". The Company believes that it is the largest U.S.
producer of SPA.

     The Company also processes phosphoric acid to produce animal feed
supplements for the poultry and livestock markets. The Albright joint venture
produces purified phosphoric acid for use in various food products and
industrial processes.

     In addition to nitrogen products, the Company also produces phosphate
products at the Geismar plant for which supplies of phosphate rock and sulfur
are necessary. PCS Nitrogen purchases phosphate rock from Morocco pursuant to an
agreement with a Moroccan government-owned company, the current term of which
expires on December 31, 2002, wherein prices are reset annually through
negotiation. If no agreement on price is reached, either party may terminate the
agreement. Changes in the agreement could affect the stability of the supply of
the raw material and the profitability of these phosphate products.

RESERVES

     At December 31, 1999, the Company's Aurora phosphate mine had estimated
proven and probable reserves of approximately 380 million tonnes of phosphate
rock, at an average grade of 30.7% P(2)O(5). These reserves would permit mining
to continue at current rates for about 75 years. The Aurora phosphate mine has
an estimated annual capacity of 6.0 million tonnes of phosphate rock and its
processing plants have the capacity to produce 1.202 million P(2)O(5) tonnes of
phosphoric acid. Prior to the acquisition of Texasgulf by the Company in April
1995, approximately 408 million tonnes of phosphate reserves were transferred by
Texasgulf to a newly established company, the common stock of which was
transferred to Elf (USA) and Williams. The Company was granted a 20-year right
of first refusal (from April 10, 1995) in the event that the newly

                                       I-6
<PAGE>   8

established company proposes to sell the reserves. In addition, the newly
established company and Elf (USA) and Williams agreed, for a period of ten years
from April 10, 1995, not to compete, and for the first five years not to make
certain preparations to compete, with the Company with respect to those
reserves.

     The White Springs phosphate mine had estimated proven and probable reserves
of approximately 53 million tonnes of phosphate rock, at an average grade of
30.7% P(2)O(5). The Company estimates that an additional 9 million tonnes of
phosphate rock could be purchased at market rates from nearby owners.
Accordingly, the total reserves of 62 million tonnes of phosphate rock at White
Springs would sustain the mine for 18 years at a mining rate of 3.6 million
tonnes per year. The White Springs mine has an estimated annual capacity of 3.6
million tonnes of phosphate rock and the processing plants have the capacity to
produce annually 1.093 million P(2)O(5) tonnes of phosphoric acid. See
"Environmental Matters -- Permits and Regulatory Approvals".

NITROGEN OPERATIONS

     The Company's nitrogen operations include production of nitrogen
fertilizers and nitrogen chemicals. These products are used for both
agricultural and industrial purposes.

PROPERTIES

     PCS Nitrogen manufactures nitrogen products at five facilities, of which
four are located in the United States and one is located in Trinidad. The
following table sets forth the facility locations and production capabilities:

<TABLE>
<CAPTION>
PLANT LOCATIONS                        PRODUCTS PRODUCED
---------------                        -----------------
<S>                                    <C>
Augusta, Georgia.....................  Ammonia, urea, nitric acid, ammonium nitrate and nitrogen
                                       solutions
Geismar, Louisiana...................  Ammonia, nitric acid, nitrogen solutions, phosphoric acid,
                                       super-phosphoric acid, phosphate solutions and sulfuric acid
Lima, Ohio...........................  Ammonia, urea, nitric acid and nitrogen solutions
Memphis, Tennessee...................  Ammonia and urea
Point Lisas, Trinidad................  Ammonia and urea
</TABLE>

     In the third quarter of 1999, in response to market conditions, the Company
announced the permanent closure of the Clinton, Iowa plant and the LaPlatte,
Nebraska plant. The Clinton plant had a capacity of 238,000 tonnes for ammonia,
79,000 tonnes of ammonia nitrate, and 163,000 tonnes for nitrogen solutions. The
LaPlatte plant had a capacity of 182,000 tonnes for ammonia and 436,000 tonnes
for nitrogen solutions.

     On December 31, 1999, the Company announced that its subsidiary, PCS
Nitrogen Trinidad Limited, indefinitely shut down its 01 and 02 ammonia plants
in Trinidad following expiration of the natural gas supply contract between the
National Gas Company ("NGC") of Trinidad and Tobago Limited and PCS Nitrogen
Trinidad Limited. The parties had been in negotiation for two years in an
attempt to secure a new agreement but were unable to bring the negotiation to an
acceptable conclusion. Active discussions with the NGC are continuing and the
Company continues to operate its two remaining ammonia plants and one urea plant
in Trinidad.

PRODUCTION

     Unlike potash and phosphate, nitrogen is not mined. It is taken from the
air and reacted with a hydrogen source, usually natural gas reformed with steam,
to produce ammonia. PCS Nitrogen produces ammonia at all domestic plants and in
Trinidad. The ammonia is used to produce a full line of upgraded nitrogen
products, including urea, ammonium nitrate, nitric acid and nitrogen solutions.

SERVICE AGREEMENTS

     The Geismar plant is integrated with a larger chemical manufacturing
complex owned by Honeywell International, Inc. ("Honeywell"). PCS Nitrogen and
Honeywell have an agreement to provide certain

                                       I-7
<PAGE>   9

support services to each other, including the provision of utilities, the
discharge of wastewater, security and emergency services, and other essential
services. PCS Nitrogen believes that most of the services that PCS Nitrogen
requires are available from other sources, if necessary. However, the
termination of, or the need to replace, certain of the services provided (such
as steam, well water supply and dock services) could, in the aggregate, involve
potentially significant capital expenditures, increased operating costs and
disruptions to the operations of the Geismar plant.

     BP Chemicals, Inc. ("BPC") operates the Lima plant on PCS Nitrogen's behalf
under an operating agreement that can be terminated by either party with nine
months' notice. PCS Nitrogen's payments to BPC under the operating agreement are
generally based on BPC's previous cost of operating the Lima plant and are made
through the reimbursement of expenses incurred by BPC in providing such
operating services. In addition, due to the mutual interdependence of the Lima
plant and BPC's operations, PCS Nitrogen and BPC have agreed to provide each
other with certain manufacturing support services at cost pursuant to a contract
extending for as long as the plants continue to operate and either party is
required to provide support services thereunder.

     PCS Nitrogen uses contract labor personnel provided by Augusta Services
Company, Inc., which is owned 50% by PCS Nitrogen and 50% by DSM Chemicals North
America, Inc., to provide purchasing, stores and spare parts management,
maintenance, repair, shipping and certain other services for the Augusta plant.

RAW MATERIALS

     Natural gas is the primary raw material used for the production of ammonia
and, as a result, virtually all of PCS Nitrogen's other nitrogen products. The
purchase and transportation of natural gas accounts for approximately 40% of PCS
Nitrogen's total domestic production cost. With the Trinidad 01 and 02 plants
running, PCS Nitrogen's domestic gas requirements comprise approximately 52% of
its total gas requirements (68% with Trinidad's 01 and 02 plants idled). PCS
Nitrogen's current natural gas strategy is to purchase approximately one-half of
its domestic natural gas in the spot market or on short-term contracts and
approximately one-half of its domestic natural gas pursuant to fixed-price
physical contracts or forward contracts which fix the price of future
deliveries. The remaining approximately 48% of its natural gas (assuming
Trinidad 01 and 02 plants are running, 32% if not) is purchased in Trinidad
using pricing formulas related to the market price of ammonia. With the
exception of the Trinidad facility, PCS Nitrogen purchases nearly all its
natural gas from producers or marketers at the point of delivery of the natural
gas into the pipeline system, then pays the pipeline company and, where
applicable, the local distribution company to transport the natural gas to PCS
Nitrogen's facilities. Approximately 85% of PCS Nitrogen's domestic consumption
of natural gas is delivered pursuant to firm transportation contracts which do
not permit the pipeline or local distribution company to interrupt service to,
or divert natural gas from, the plant.

PCS JOINT VENTURE

     The Company indirectly holds all outstanding interests in a limited
partnership (the "PCS Joint Venture") doing business in Florida as Florida
Favorite Fertilizer and in Georgia and Alabama as Farmer's Favorite Fertilizer.
PCS Joint Venture manufactures, processes and distributes fertilizer and other
agricultural supplies from plants located in Florida, Alabama and Georgia.

                                       I-8
<PAGE>   10

MARKETING

     The following table summarizes the Company's net sales revenue of potash,
phosphate and nitrogen products (by nutrient) in the past three calendar years:

<TABLE>
<CAPTION>
                                                               1999        1998        1997
                                                             --------    --------    --------
                                                                  (THOUSANDS OF DOLLARS)
<S>                                                          <C>         <C>         <C>
Potash
  Canada...................................................  $ 21,429    $ 21,885    $ 14,460
  United States............................................   215,993     205,701     195,780
  Canpotex.................................................   254,711     252,464     229,666
  Other....................................................    71,163      65,441      64,261
Phosphates
  Canada...................................................    24,010      25,386      24,268
  United States............................................   594,183     688,198     632,616
  PhosChem.................................................   186,494     262,168     261,502
  Other....................................................    39,153      35,237      35,223
Nitrogen
  Canada...................................................     5,284       4,422       2,879
  United States............................................   480,213     585,672     694,566
  Other....................................................   168,431     161,189     170,708
Florida Favorite Fertilizer................................    52,850      55,344      57,156
</TABLE>

     The following table summarizes the Company's net sales revenue from
products, by category:

<TABLE>
<CAPTION>
                                                               1999        1998        1997
                                                             --------    --------    --------
                                                                  (THOUSANDS OF DOLLARS)
<S>                                                          <C>         <C>         <C>
Potash.....................................................  $563,296    $545,491    $504,167
Florida Favorite Fertilizer................................    52,850      55,344      57,156
Phosphates
  Liquid Fertilizers.......................................   268,903     331,672     283,110
  Solid Fertilizers (DAP, MAP, GTSP).......................   283,455     374,525     362,625
  Animal Feed..............................................   176,783     187,557     191,016
  Phosphate Rock, Industrial Products......................   114,699     116,544     116,858
Nitrogen
  Ammonia..................................................   244,719     258,387     376,972
  Urea.....................................................   180,545     200,103     209,825
  Nitrogen Solutions.......................................   111,080     163,018     162,885
  Other....................................................   117,584     129,775     118,472
</TABLE>

     For further financial information about the Company's business segments and
domestic and international sales, see Note 18 to the Consolidated Financial
Statements.

     The Company has a diversified customer base, and apart from sales to
Canpotex Limited ("Canpotex") and Phosphate Chemicals Export Association, Inc.
("PhosChem"), no one customer accounted for more than 10% of the Company's sales
in 1999.

     Potash from the Company's Saskatchewan mines produced for use outside North
America is sold exclusively to Canpotex. PCS Sales (Canada) Inc. executes
offshore marketing and sales for the Company's New Brunswick potash and executes
marketing and sales for the Company's potash, phosphate and nitrogen products in
Canada. PCS Sales (USA), Inc. executes marketing and sales for the Company's
potash, phosphate and nitrogen products in the United States. PhosChem, an
association formed under the U.S. Webb-Pomerene Act, is the principal vehicle
through which the Company executes offshore marketing and sales for its
phosphate fertilizers. See "Offshore Marketing".

                                       I-9
<PAGE>   11

     Ammonia, urea, ammonium nitrate and nitrogen solutions are sold as
fertilizers to agricultural customers and to industrial customers for various
applications, while nitric acid is sold to industrial customers as an
intermediate chemical feedstock.

     In the past, fertilizer prices have been volatile. No assurance can
therefore be given that the average market prices for the Company's fertilizer
products will continue at current levels.

NORTH AMERICAN MARKETING

     In 1999, North American net sales revenue from potash products represented
12% of the Company's total net sales revenue, substantially all of which was
attributable to potash customers in the United States. Typically, North American
potash sales of the Company are greatest in the second calendar quarter. The
vast majority of sales are made on the spot market with the balance made under
short-term contracts. The Company has no material contractual obligations in
connection with North American sales to sell potash in the future at a fixed
price.

     In 1999, North American net sales revenue from phosphate products
represented 30% of the Company's total net sales revenue, substantially all of
which was attributable to phosphate customers in the United States. Typically,
North American phosphate product sales are greatest in the first and second
calendar quarters. In 1999, the majority of PCS Phosphate's phosphate product
sales were made on the spot market, with the balance made under short-term
contracts (generally on an annual basis) and a limited number of sales made
pursuant to multi-year contracts. The Company has no material contractual
obligations in connection with North American sales to sell phosphate in the
future at a fixed price.

     In 1999, North American net sales revenue from nitrogen products
represented 29% of the Company's total net sales revenue and PCS Nitrogen's
non-fertilizer products accounted for approximately 47% of PCS Nitrogen's
nitrogen revenue. Typically, North American nitrogen fertilizer sales are
greatest in the second calendar quarter. In 1999, the majority of PCS Nitrogen's
nitrogen product sales were made on the spot market, with the balance made under
short-term and multi-year contracts. The Company has no material contractual
obligations in connection with North American sales to sell nitrogen in the
future at a fixed price.

     Ammonia purchased by PCS Nitrogen is used in the Company's operations and
is sold to third party customers by PCS Sales (USA), Inc.

     The primary customers for fertilizer products are retailers, dealers,
cooperatives, distributors and other fertilizer producers. Such retailers,
dealers and cooperatives have both distribution and application capabilities.
The primary customers for industrial products are chemical product
manufacturers.

     At December 31, 1999, the Company's North American sales functions were
handled by 78 employees in Chicago, Illinois and various other locations in the
United States, and 17 employees in Saskatoon, Saskatchewan.

OFFSHORE MARKETING

     Potash produced by the Company in Saskatchewan for sale outside North
America is sold to Canpotex, which is owned in equal shares by the three potash
producers in the Province of Saskatchewan (including the Company). Canpotex,
which was incorporated in 1970 and commenced operations in 1972, acts as an
export company and as a unified marketing force for all Saskatchewan potash
production in the offshore marketplace. Each shareholder of Canpotex has an
equal voting interest as a shareholder and through its nominees on the board of
directors. The Company and the other shareholders of Canpotex have agreed that,
as long as they are members of Canpotex, and with respect to potash produced in
Canada, they will not make offshore sales independently. The Company's
production from its New Brunswick mine has been exempted from this requirement
by the members of Canpotex. Any member may terminate its membership in Canpotex
at specified times of the year on six months notice.

     In general, Canpotex sales are allocated among the producers based on
production capacity. If a shareholder cannot satisfy demand for potash by
Canpotex, the remaining shareholders are entitled to satisfy

                                      I-10
<PAGE>   12

the demand pro rata based on their allotted production capacity. The Company
currently supplies 55.65% of Canpotex's requirements. Canpotex sells potash to
government agencies and private firms pursuant to six-month contracts at
negotiated prices or by spot sales.

     The following table sets forth the percentage of sales by Canpotex for the
past three calendar years in the various geographical regions:

<TABLE>
<CAPTION>
                                                              1999    1998    1997
                                                              ----    ----    ----
<S>                                                           <C>     <C>     <C>
Asia........................................................  75%     69%     72%
Latin America...............................................  13      17      14
Oceania.....................................................  8       9       9
Europe......................................................  4       5       5
                                                              ----    ----    ----
Total.......................................................  100%    100%    100%
                                                              ====    ====    ====
</TABLE>

     For 1999, sales to Canpotex represented 12% of the total net sales of the
Company and net sales revenue from offshore sales of potash from the New
Brunswick mine, through PCS Sales (Canada) Inc., represented 3% of the total net
sales of the Company.

     Since 1975, PhosChem has been the principal vehicle for United States
exports of phosphate fertilizers. Currently, the members of PhosChem are PCS
Phosphate, IMC-Agrico Company ("IMC-Agrico"), a joint venture between IMC Global
Inc. and Phosphate Resource Partners LLP, Mississippi Phosphates Corporation
("MissChem") and Mulberry Corporation. The PhosChem members have agreed to
export their fertilizer products exclusively through PhosChem, except for
exports to Canada, any member state of the European Union or the European
Economic Area, and sales through the U.S. Agency for International Development
Tenders and sales to certain buyers affiliated with members. Historically,
PhosChem negotiated prices and other terms for the export sale of fertilizer
products. According to the terms of a PhosChem agreement effective January 1,
1995, IMC-Agrico is responsible for the marketing of solid fertilizers (DAP, MAP
and GTSP), and PCS Phosphate, or its sales affiliate (PCS Sales (USA), Inc.), is
responsible for the marketing of liquid fertilizer products (MGA) to export
countries. Total sales for 1999 were apportioned as follows: 62% to IMC-Agrico,
20% to PCS Phosphate, 8% to MissChem, and 10% to Mulberry Corporation. The
PhosChem agreement is currently in effect through December 31, 2000, and subject
to renewal thereafter. If the PhosChem agreement is not renewed, the Company
does not believe the disbanding of PhosChem would materially affect the
Company's sales of fertilizer, but there can be no assurance that, if PhosChem
were to be disbanded, the Company would be able to find alternative outlets for
its products or sell its products at prices or on terms similar to those
expected to be obtained by PhosChem. The Company's estimated 2000 PhosChem
allocation is 22.56%.

     Revenue from sales to PhosChem accounted for 9% of the Company's total net
sales in 1999. Other offshore phosphate sales accounted for 2% of the Company's
total net sales in 1999. All of the Company's phosphate sales to China and India
were made through PhosChem. Most of the Company's sales of phosphate products to
China are made to the central purchasing authority of the Chinese government.
Sales in India were made through the Fertilizer Association of India to many
independent buyers.

     The following table sets forth the percentage of sales of PhosChem for the
past three calendar years in the various geographical regions:

<TABLE>
<CAPTION>
                                                              1999    1998    1997
                                                              ----    ----    ----
<S>                                                           <C>     <C>     <C>
Asia........................................................  81%     77%     75%
Latin America...............................................  11      14      15
Mid East....................................................  --      1       2
Oceania.....................................................  8       8       8
                                                              ----    ----    ----
Total.......................................................  100%    100%    100%
                                                              ====    ====    ====
</TABLE>

                                      I-11
<PAGE>   13

     With respect to offshore sales of nitrogen, ammonia and urea sales
predominate and originate primarily from Trinidad, with other sales coming from
purchased product locations. For 1999, net sales revenue from offshore sales of
nitrogen represented 3% of the net sales revenue of the Company.

     Offshore sales are subject to those risks customarily encountered in
foreign operations, including (i) fluctuations in foreign currency exchange
rates, (ii) changes in currency and exchange controls, (iii) the availability of
foreign exchange, (iv) laws, policies and actions affecting foreign trade and
(v) other economic, political and regulatory policies of foreign governments.

DISTRIBUTION AND TRANSPORTATION

     The Company has an extensive infrastructure and distribution system to
transport and store its products. Other than storage facilities located at
production plants, in 1999 the Company used 147 locations to store and handle
its products in the field. The Company owns or net leases 2,003 railcars and
full service leases an additional 3,634 railcars.

     Transportation costs add significantly to the total amounts paid by
purchasers of potash. Producers have a definite advantage in markets close to
their sources of supply (e.g., Saskatchewan producers in the Midwestern United
States, New Brunswick producers on the U.S. Eastern Seaboard and New Mexico
producers in the Southern and Western United States). International shipping
cost variances permit offshore producers (including those in the former Soviet
Union ("FSU"), Germany, Israel and Jordan) to compete effectively in some of the
Company's traditional markets.

     Most of the Company's potash for North American customers is shipped by
rail. Shipments are also made by rail from each of the Company's Saskatchewan
mines to Thunder Bay, Ontario, for shipment by lake vessel to the Company's
warehouses and storage facilities in Canada and the United States.

     Potash from the New Brunswick mine is shipped primarily by ocean-going
vessel from the Port of Saint John, although truck and rail transport are also
used for North American customers.

     In the case of the Company's sales to Canpotex, potash is transported by
rail principally to Vancouver, British Columbia, where port facilities exist for
storage pending shipment overseas. The Company has an equity interest in
Canpotex Bulk Terminals Limited, which is a part owner of these port facilities.
The Company, through Canpotex, also has an interest in a port facility located
in Portland, Oregon.

     With respect to phosphates, the Company has long-term leases on shipping
terminals in Morehead City and Beaufort, North Carolina, through which it
receives and stores raw materials for, as well as the products manufactured by,
the Aurora Facility. The Company owns nine barges (four used for solid products,
two for phosphoric acid, one for sulfuric acid and two for sulfur) and three tug
boats, which are used to transport materials between its Aurora Facility and
Morehead City. Raw materials and products are also transported to and from the
Aurora Facility by rail. The Company transports sulfur it purchases from Canada
in large, dedicated unit trains. Both CSX Corporation and Norfolk Southern
Corporation serve the Aurora Facility. The Company believes that its location
and diversified transportation and terminalling capabilities put it in a
comparable position to most of its Florida competitors in purchasing sulfur. In
December 1997, the Company entered into a ten-year supply contract with an
offshore supplier to supply a portion of the Company's sulfur requirements and
also committed to build a multipurpose ocean-going vessel to ship such sulfur as
well as handle sulfuric acid, phosphoric acid and other chemicals. The vessel is
expected to be in service in the first half of 2000. The Company receives
ammonia for its phosphate operations at Aurora through its ammonia terminal in
Savannah, Georgia; the ammonia is shipped by rail from Savannah to the Aurora
Facility.

     Sulfur is delivered to the White Springs Facility by unit trains from
Canada and by rail from multiple domestic sources. The Company receives ammonia
for its phosphate operations at White Springs through its ammonia terminal in
Savannah, Georgia; ammonia is shipped by rail from Savannah to the White Springs
Facility. Until 1999 the Norfolk Southern Corporation was the only railroad
providing service for the White Springs Facility. However, a nearby transload
facility at Lake City, Florida, which became operational in 1999, is serviced by
the CSX Corporation. Most of the phosphoric acid and chemical fertilizers
produced at the White Springs Facility are shipped to domestic destinations by
rail. The Company also ships some of its
                                      I-12
<PAGE>   14

phosphoric acid, chemical fertilizers and animal feed products, produced at the
White Springs Facility, through the bulk terminal located in Morehead City,
North Carolina, for offshore sales. This latter option allowed the Company to
close the more costly Jacksonville, Florida terminal.

     The Company makes domestic deliveries of animal feed products (bulk and
bagged) by rail or truck from its manufacturing facilities and from several
warehouses supplied from its manufacturing facilities.

     The Company distributes its nitrogen products by barge, railcar, truck, and
direct pipeline to its customers and through its strategically located storage
terminals in high consumption areas. The Company leases or owns approximately 50
nitrogen terminal facilities with an aggregate storage capacity of approximately
600,000 tons of product. The terminals provide off-season storage and also serve
local dealers during the peak seasonal demand period.

     The Company distributes products from the Trinidad plant to markets in
Latin America and Europe in addition to the United States. The Company's
distribution operations in Trinidad employ two long-term chartered ocean-going
vessels and utilize spot charters as necessary for the transportation of
ammonia. All bulk urea production is shipped through third-party carriers.

COMPETITION

     The markets for potash, both domestic and foreign, are highly competitive.
Since potash is a commodity, producers must compete based on price and service
(e.g., delivery time and ability to supply all grades). Apart from competitive
pricing, the Company's principal method of competition is the quality of service
it provides to customers. Among other things, the Company provides quality
service by maintaining warehouses and leasing railcars to enhance its delivery
capability. The high cost of transporting potash limits competition in various
areas.

     The Company's potash competition includes three North American producers
and potash producers located outside North America in the FSU, Israel, Jordan,
Germany and France. Because of the high capital cost and lead time required to
construct a new mine, the Company's principal competition is expected to
continue to come from the owners of existing operations.

     Most phosphate products, particularly solid fertilizers, are commodities,
with little or no product differentiation, and thus trade on the basis of prices
determined in highly competitive markets. The vast majority of the U.S.
phosphate rock not mined by the Company is produced in central Florida,
southeast of Tampa, and most of the U.S. phosphate processing capacity, other
than at Aurora, is located in Florida and along the coast of the Gulf of Mexico.

     The Company's principal advantage at Aurora in competing with other
producers is that it operates integrated phosphate mine and phosphate processing
complexes while most of its competitors are required to ship phosphate rock by
rail or truck from their mines to their chemical processing plants, thus
incurring substantially higher transportation costs.

     As a result of its location in North Carolina and the relatively high cost
of transportation, the Company's U.S. phosphate sales from Aurora have a natural
advantage in the Northeast, mid-Atlantic and eastern Midwest regions, while
White Springs and other Florida producers have a natural advantage in the South,
and Gulf coast producers have a natural advantage in areas of the Midwest
accessible to barge traffic up the Mississippi River.

     The Company also competes with governmental enterprises and independent
phosphate producers in important exporting countries, including Morocco,
Tunisia, Jordan and South Africa.

     Although there has been extensive consolidation and privatization
worldwide, substantial competition exists in the nitrogen industry. The Company
competes domestically with a broad range of companies in the production and sale
of nitrogen products, including subsidiaries of larger chemical companies, farm
cooperatives, integrated energy companies and independent fertilizer companies.
Because fertilizer is a commodity, competition takes place largely on the basis
of price and delivery. The relative cost of, and

                                      I-13
<PAGE>   15

availability of transportation for, raw materials and finished products to
manufacturing facilities and markets are important competitive factors.

     The Company also competes with foreign companies whose nitrogen products
are imported into the United States. Although diminishing in number, various
foreign competitors receive subsidies from their governments. Some countries
also have natural gas supplies that are surplus to domestic demand. This surplus
natural gas may have a low alternative value and, when used as feedstock for the
manufacture of ammonia and urea, can result in low-cost production. These
low-cost products are being imported into the U.S. and compete with domestically
manufactured nitrogen fertilizers, including the Company's. In addition, other
importers subsidized by their governments may import products into the U.S. for
reasons not related to U.S. fertilizer market conditions, such as a need to
obtain U.S. dollars.

     Pursuant to the Uruguay Round Agreements Act, on March 1, 1999, the U.S.
Department of Commerce and the U.S. International Trade Commission commenced a
"sunset" review of antidumping orders restricting exports of urea from the FSU
and Romania into the United States in order to determine whether such orders
should be terminated or should remain in effect. Effective October 1999, those
agencies determined that the antidumping orders should remain in effect for
Romania and substantially all relevant FSU states.

     The Company's nitrogen production capability is currently the largest in
the Western Hemisphere. The Company's domestic nitrogen plants serve
agricultural markets with a diversified crop base that spans a lengthy growing
season and chemical industrial manufacturers located throughout the U.S. Those
plants are strategically located in agricultural as well as industrial end-use
markets in the Southeast, Midwest and Gulf Coast regions. The Company believes
that it is more economical to transport natural gas, the primary raw material in
the production of nitrogen fertilizers and chemicals, to plants situated in the
product markets than to transport such products over long distances. Several of
the Company's domestic nitrogen plants are located closer to their primary
customers than are their competitors. The Company concentrates its nitrogen
marketing efforts on these nearby markets where lower transportation costs offer
the potential for better margins. The Company believes that its product mix
diversity and the number and geographic diversity of its nitrogen plants provide
competitive advantages in manufacturing, distribution, marketing, customer
service and other areas when compared to competitors controlling only a few
facilities. In addition, the industrial demand for nitrogen products is
typically less volatile and follows different demand cycles than agricultural
demand for fertilizer. The Company believes that its industrial sales add a
measure of stability to its revenue and are a desirable complement to
agricultural demand.

EMPLOYEES

     At December 31, 1999, the Company actively employed 5,506 persons, of whom
1,899 were salaried and 3,607 were hourly paid. Of these employees, the
Company's potash operations employed 1,736 people, the phosphate operations
employed 2,615 people, the nitrogen operations employed 966. The corporate
office had a staff of 94 and 95 people were employed in the Company's sales
group.

     The Company has entered into nine collective bargaining agreements with
labor organizations representing employees. The collective bargaining agreements
at the Allan, Cory and Patience Lake divisions expire on April 30, 2000. The
Lanigan agreement expires on January 31, 2001. The Company and the Rocanville
Potash Employees Association have a contract that expires on May 31, 2001. The
agreement between IMC and the union representing the employees at the Esterhazy
mine expires on January 31, 2001. The union agreement at PCS Cassidy Lake
expired December 31, 1998 and negotiations are continuing. The Company's Sussex,
New Brunswick and Aurora operations are non-union. The collective bargaining
agreement with the union representing employees at the White Springs plant
expires on December 1, 2000 and the agreement with the employees at the
Jacksonville terminal expires September 30, 2001. PCS Nitrogen has three
locations with collective bargaining agreements: Clinton, which contract expired
July 31, 1999 but has been extended to May 1, 2000; Memphis, which contract
expires September 17, 2000; and LaPlatte, with a contract that expires January
31, 2003. Clinton and LaPlatte were permanently closed in the third quarter of
1999. In addition, the agreement between BPC and the union representing
employees at the Lima plant expires February 16, 2002. The Company believes its
relations with its employees to be good.

                                      I-14
<PAGE>   16

ROYALTIES AND CERTAIN TAXES

     Saskatchewan potash production is taxed at the provincial level under The
Mineral Taxation Act, 1983 (Saskatchewan). This tax consists of a base payment
and a profit tax. In addition to the Potash Production Tax, rental fees, taxes
and royalties are payable to the Province of Saskatchewan and municipalities by
potash producers in respect of potash reserves or production of potash in the
Province of Saskatchewan. The Company's taxes, fees and royalty expenses were
$72.7 million in 1999.

     The Company is subject to capital tax on its paid-up capital (as defined in
The Corporation Capital Tax Act of Saskatchewan) and its taxable capital (as
defined in the New Brunswick Income Tax Act). In addition, a resource
corporation in the Province of Saskatchewan pays a corporate capital tax surtax
based on the value of Saskatchewan resource sales. This surtax is only payable
to the extent that it exceeds the regular capital tax. In 1999, the Company paid
capital tax of $3.8 million and surtax of $15.3 million.

     The Company pays royalties to the New Brunswick government on the basis of
production from its New Brunswick mine. In addition, the Company pays municipal
taxes. The Company's expenses for such royalties and municipal taxes were $5.0
million in 1999.

     The Company does not make royalty payments in connection with its phosphate
and nitrogen operations.

INCOME TAXES

     PCS and certain subsidiaries are subject to federal income taxes (which
includes the Large Corporations Tax) and provincial income taxes in Canada.
During 1999, the Company began accruing cash income taxes by virtue of having
fully utilized non-capital losses carried forward.

     The subsidiaries of the Company which operate in the United States are
subject to U.S. federal and state income taxes. These subsidiaries are not
currently subject to federal cash income taxes by virtue of net operating losses
incurred. The Company's nitrogen subsidiaries operating in Trinidad are subject
to Trinidad taxes.

     The effective consolidated tax rate for 1999 was 30% (1998 -- 31%) of
income before income taxes (exclusive of the goodwill impairment charges
recorded in the third quarter of 1999). The reduction in total income tax
expense was principally due to a deferred tax recovery of $48.6 million relating
to the plant closures and impairment charge and lower income before income
taxes.

RESEARCH AND DEVELOPMENT

     The Company maintains potash research and development facilities located in
Saskatoon, Saskatchewan, employing approximately 30 persons who concentrate on
improving efficiency in mine operations and product quality. Research continues
on the use of three-dimensional seismic methods and other geophysical tools to
detect geological disturbances in potash ore bodies. The Company is also
proceeding with automation of mining machines and improving process control in
mills. Other research includes new product development and measures to maintain
and enhance product quality in transit and at offsite storage facilities. The
Company funds research in agronomy through Potash & Phosphate Institute
programs.

     The Company continues to evaluate ways to more fully automate its phosphate
production facilities, including improvements to its beneficiation (mill),
sulfuric acid and phosphoric acid plants. The Company is also exploring ways of
further debottlenecking its phosphate and nitrogen production facilities,
selectively adding capacity and otherwise enhancing production and process
efficiencies through technological enhancements. The Aurora Facility has
increased direct blending of gypsum and clays which the Company expects should
reduce long-term gypsum handling and reclamation costs.

ENVIRONMENTAL MATTERS

     Certain environmental matters which are the subject of investigation or
litigation are discussed under the heading "Legal Proceedings". The Company's
operations are subject to numerous environmental requirements under Canadian,
U.S., Chilean and Trinidad and Tobago federal, provincial, state and local laws
                                      I-15
<PAGE>   17

and regulations. Such laws and regulations govern, among other matters, air
emissions, waste water discharges, land use and reclamation and solid and
hazardous waste management. Many of these laws and regulations are becoming
increasingly stringent, and the cost of compliance with these requirements can
be expected to increase over time. In particular, Trinidad and Tobago
governmental authorities are considering measures providing for the increased
regulation of environmental matters, including the potential implementation of
more stringent wastewater effluent standards which may require PCS Nitrogen to
take certain actions to maintain compliance. Nonetheless, PCS Nitrogen does not
currently expect that such legislation or regulations will have a material
adverse effect on the Company's financial condition or results of operations.

     The Company believes that it is currently in material compliance with
applicable environmental laws and regulations. The Company believes that it is
well positioned to meet anticipated requirements under the applicable
environmental laws and regulations. Although significant capital expenditures
and operating costs have been incurred and will continue to be incurred on
account of environmental laws and regulations, the Company does not believe,
except as otherwise set out herein, that such environmental laws and regulations
have had, or will have, a material adverse effect on its business. However, the
Company cannot predict the impact of new or changed laws or regulations or
permit requirements, including the recently-enacted potash decommissioning
regulations discussed below or changes in the ways that such laws and
regulations are administered or interpreted. The Company anticipates that its
routine expenditures related to environmental regulatory matters in 2000 will
not differ materially from the previous year.

     The Company and its facilities are also subject to a range of environmental
statutes and programs focused on site reclamation and restoration and on
investigation and, where necessary, remediation of contaminated properties. The
Company's obligations and potential liabilities under these programs have been
and can be expected to continue to be significant. The Company does not believe,
except as set out herein, that such obligations and potential liabilities have
had, or will have, a material adverse effect on its business. However, it is
often difficult to estimate and predict the potential costs and liabilities
associated with these programs and there is no guarantee that the Company will
not in the future be identified as potentially responsible for additional costs
under these programs, either as a result of changes in existing laws and
regulations or as a result of the identification of additional matters or
properties covered by these programs.

ENVIRONMENTAL EXPENDITURES

Reclamation and Restoration Costs

     Site restoration and reclamation costs have been accrued for various sites.
At December 31, 1999, the Company had accrued the following amounts for site
reclamation and restoration: $28.5 million for the Aurora Facility, $55.8
million for the White Springs, Florida Facility, $27.4 million for the Moab,
Utah Facility, $0.6 million for various idle sulfur facilities, $18.4 million
for certain Florida Favorite Fertilizer facilities, and $4.3 million for the
Cassidy Lake Facility. The idle sulfur facilities were part of the acquisition
of Texasgulf and are undergoing dismantlement and environmental restoration
efforts. The current portion of restoration and reclamation costs accrued in
1999 totaled $22.7 million. These amounts represent the Company's current
estimate of potential site restoration and reclamation costs as last assessed in
December 1999. The expenditures are generally incurred over an extended period
of time.

     Annual environmental expenditures for reclamation and restoration during
the year ended December 31, 1999 were $79.3 million. Of this amount, $70.3
million was charged to operations, $3.1 million was capitalized and $5.9 million
was charged against accrued reclamation costs.

Capping of By-product Gypsum Stacks

     In 1993, the State of Florida passed certain legislation requiring
companies to reduce the potential environmental hazards associated with
accumulations of by-product gypsum (gypsum stacks). The regulations implementing
this legislation require companies to "cap" the gypsum stacks in order to reduce
seepage into groundwater when such stacks reach their design capacity (for the
Company, in approximately 35 years), or after March 25, 2001 if groundwater
standards are not being met. At December 31, 1999, a balance of $35.4 million
was included in accrued reclamation costs for this gypsum stack capping
requirement.
                                      I-16
<PAGE>   18

The obligations of White Springs regarding the gypsum stacks are guaranteed by
PCS (see "Permits and Regulatory Approvals").

     In North Carolina, on exhaustion of the mine's phosphate reserves,
disposition of the remaining gypsum must comply with the laws in effect at that
time.

Other Environmental Costs

     The Company's operating expenses, other than reclamation and restoration
and gypsum stack capping, relating to compliance with environmental laws and
regulations governing ongoing operations were approximately $20.2 million for
the year ended December 31, 1999 as compared to $20.5 million for the year ended
December 31, 1998.

Capital Expenditures

     The Company routinely undertakes capital projects to improve pollution
control facilities. In 1999, a total of approximately $5.1 million in capital
expenditures (exclusive of capitalized reclamation expenditures) was spent to
meet the Company's environmental control objectives as compared to $9.9 million
in 1998. The Company expects that its capital requirements for environmental
projects may increase in the future due to increasingly stringent environmental
regulations arising from current and future requirements of law.

     With respect to air emissions, the Company anticipates that additional
expenditures may be required to meet increasingly stringent U.S. federal and
state regulatory and permit requirements. These requirements include existing
and anticipated regulations under the U.S. federal Clean Air Act, particularly
the 1990 amendments thereto, and under state law. In particular, both federal
and state regulation of hazardous air pollutants (including ammonia in certain
states) are expected to require additional air emission control equipment and
increased operating expenditures at some U.S. facilities. Further, the U.S.
Environmental Protection Agency ("EPA") has published new National Ambient Air
Quality Standards for both ozone and particulate matter which are more stringent
than existing standards and has issued a number of regulations establishing
requirements to reduce nitrogen oxide (NOx) emissions. The Company continues to
monitor developments in these various programs and to assess their potential
impact on the Company's operations.

     The federal Clean Air Act operating permit program is expected to require
the addition of enhanced emissions monitoring equipment at some facilities, as
well as the imposition of permit fees based upon facility air pollutant
emissions. If the Company undertakes facility expansion at its U.S. plants, a
federal Prevention of Significant Deterioration or New Source Review Permit may
need to be obtained prior to any such expansion of these facilities. Such
permits would impose certain restrictions on air pollutant emissions from the
expanded portions of such plants and compliance with those restrictions would
likely require installation and use of additional pollution control devices.

SITE ASSESSMENT AND REMEDIATION

     In addition to environmental regulation of its present operations, the
Company also may incur costs and liabilities in connection with its and its
predecessors' past and present waste disposal practices and ownership and
operation of real property and facilities, as well as its mining activities. The
U.S. federal Comprehensive Environmental Response, Compensation and Liability
Act of 1980 ("CERCLA") and other U.S. federal and state laws impose liability
on, among others, past and present owners and operators of properties or
facilities at which hazardous substances have been released into the environment
and persons who arrange for disposal of hazardous substances that are released
into the environment. Liability under these laws may be imposed jointly and
severally and without regard to fault or the legality of the original actions,
although such liability may be divided or apportioned according to various
equitable and other factors. In the course of its present and former operations,
including those of divested businesses, PCS Phosphate, White Springs and PCS
Nitrogen have generated and the Company will generate wastes that could result
in liability for the Company under these laws.

                                      I-17
<PAGE>   19

     During the past ten years, EPA officials or EPA contractors have conducted
and completed independent, limited site assessments at Aurora, Marseilles and
Saltville facilities. The Company has no information indicating that any cleanup
required in connection with the Aurora, Marseilles and Saltville sites will have
a material adverse effect upon the Company's financial condition or results of
operation. Further, the Company believes that if it has any material liability
for such costs, it would have claims against third parties in connection with
such liability. Any such claims would be based on statutory and/or common law
causes of action against third parties, such as former owners, occupiers or
disposers.

     PCS Phosphate was initially named as a potentially responsible party in two
cleanup matters involving the Colorado School of Mines Research Institute
("CSMRI") in connection with hazardous substances allegedly generated at some of
the former operations of CSMRI. During May, 1995, Elf (USA) advised EPA that Elf
(USA) was handling the matter on behalf of Texasgulf and another former Elf
(USA) subsidiary, Texasgulf Metals and Minerals Co. On January 28, 1997, EPA
issued a notice that the required cleanup work at one of the sites had been
completed. To date, PCS Phosphate has had no further involvement with these
matters.

     PCS Joint Venture and its general partner, Potash Corporation of
Saskatchewan (Florida) Inc. ("PCS Florida"), a wholly-owned subsidiary of the
Company, are subject to various environmental laws of the federal and local
governments in the United States, and from time to time investigations relating
to such laws. Currently, the Florida Department of Environmental Protection
("FDEP") is conducting an investigation into soil and ground water contamination
of a PCS Joint Venture fertilizer plant located in Lakeland, Florida and certain
adjoining property. Assessment of the contamination of the plant site and of
certain adjoining property is continuing. On April 8, 1997, FDEP filed a
Complaint and Petition for Enforcement against PCS Joint Venture and others. The
Company filed an Answer, Affirmative Defenses and Cross Claims on May 12, 1997.
Discovery is still continuing in this litigation.

     On October 30, 1998, EPA notified the Company of potential liability under
Section 107(a) of CERCLA. On December 1, 1998, the Company replied to EPA's
Initial Information Request. By letter dated February 8, 1999, the EPA notified
PCS Joint Venture that the EPA was initiating a period for negotiations to
assist in the preparation of an Administrative Order on Consent and a Remedial
Investigation and Feasibility Study ("RI/FS") Work Plan. On October 13, 1999,
PCS Joint Venture submitted to the EPA Phase I of a work plan to conduct a RI/FS
of certain releases to the soil and groundwater of the PCS Joint Venture
facility in Lakeland, Florida and other area properties (the "Landia Site"). On
October 21, 1999, PCS Joint Venture signed an Administrative Order by Consent
under which PCS Joint Venture agreed to conduct the RI/FS work. PCS Joint
Venture is in the process of implementing the agreed upon RI/FS work plan.
Starting in September 1999, the EPA conducted additional investigations of
environmental conditions at focused areas of the Landia site. In February 2000,
the EPA notified PCS Joint Venture and two other entities of the Agency's intent
to undertake interim site response activities at specific areas of the Landia
Site. The Notice letter also advised PCS Joint Venture of an opportunity to
negotiate with the EPA regarding a commitment to conduct these site response
activities pursuant to a proposed Administrative Order on Consent. On March 17,
2000 PCS Joint Venture and another entity advised the EPA that they had reached
an agreement in principle between themselves and were willing, subject to the
negotiation of an acceptable scope of work and Administrative Order on Consent,
to undertake certain of the interim response activities at the Landia Site. PCS
Joint Venture intends to defend itself vigorously in all legal proceedings while
also continuing to work to assess and evaluate the nature and extent of the
impacts at the Site. No final determination has yet been made of the nature,
timing, or cost of remedial action that may be needed, and PCS Joint Venture is
unable at present to determine whether and to what extent it may be able to
recover any costs incurred from third parties.

     In June 1994, the Georgia Department of Natural Resources, Environmental
Protection Division ("GEPD") wrote to PCS Joint Venture seeking certain
environmental information regarding its Moultrie, Georgia location. In October
1994, an additional request for information was received from the EPA pursuant
to Section 104(e) of CERCLA. Responses to both requests have been provided by
PCS Joint Venture. Preliminary investigations have confirmed the presence of
lead-contaminated soil at the site. The initial assessment is that this lead
contamination is attributable to former operations at the site, the facilities
of which were dismantled some time ago. However, a complete assessment of the
site has not yet been completed, and
                                      I-18
<PAGE>   20

the full nature and extent of the contamination cannot be quantified at this
time. On September 30, 1997, the GEPD requested that Farmers Favorite Fertilizer
submit a Compliance Status Report ("CSR") by March 30, 1998, pursuant to the
applicable state site remediation program. A consultant prepared and submitted
the CSR for Farmers Favorite Fertilizer. On September 22, 1998, GEPD requested
that a revised CSR be prepared and submitted by December 31, 1998. On December
15, 1998, a Request for Extension to File the revised CSR was submitted to GEPD,
seeking an extension to complete needed field work and correspondingly revise
the CSR. GEPD and Farmers Favorite Fertilizer executed a Consent Order
authorizing the extension. The revised CSR was submitted during March 1999. At
the request of GEPD, Florida Favorite Fertilizer had prepared and had filed
during July 1999 a Corrective Action Plan. No recommended course of action has
yet been approved by GEPD.

     PCS Joint Venture is co-operating with regulatory authorities in their
investigations of the Lakeland and Moultrie sites. It is also attempting to
determine the number and location of other parties who may be liable for
remediation of these sites. However, because site assessments are ongoing and
because other parties may be liable for some or all costs of remediation, the
ultimate liability of PCS Joint Venture has not yet been determined.

     The Company received a request for information dated August 28, 1998, from
the United States Department of Agriculture Forest Service ("USDA Forest
Service") alleging that a subsidiary of Texasgulf, dissolved over forty-five
years ago, may have contributed to environmental impacts in the Klamath National
Forest in northern California. In a letter dated November 2, 1998, a
representative of the Washoe Tribe of Nevada and California invited the Company
to evaluate its potential liability and to participate in an assessment of
natural resource damages in connection with the Leviathan mine in Northern
California. The Company has advised the USDA Forest Service that the Company
does not believe it is a potentially responsible party with respect to the
alleged impacts. The Company has advised the Washoe Tribe that the Company did
not wish to participate in the assessment.

     In February 1996, the North Carolina Department of Environment, Health and
Natural Resources notified PCS Nitrogen that the Navassa, North Carolina
terminal site had been included on the state's Inactive Hazardous Waste Sites
Priority List. Listed sites normally are subject to detailed assessment of the
environmental condition of concern and the feasible remediation options. PCS
Nitrogen nonetheless currently expects that the cost and liability, if any,
associated with the Navassa terminal site will not have a material adverse
effect on the Company's financial condition or results of operations.

     PCS Nitrogen, in 1991, voluntarily installed a remediation system at the
Memphis plant to address certain contaminants found in the groundwater. In 1993,
the Tennessee Department of Environment and Conservation ("TDEC") proposed to
include the Memphis plant on the state's list of Inactive Hazardous Substance
Sites, potentially requiring further assessment and remedial actions. In
response to that proposal, PCS Nitrogen in 1994 entered into a consent agreement
with the TDEC providing instead for its oversight and possible modification of
PCS Nitrogen's current remedial action. While there can be no assurance that the
Memphis plant will not be listed in the future, PCS Nitrogen does not expect
that costs associated with such listing would have a material adverse effect on
the Company's financial condition or results of operations.

     Since 1990, pursuant to ongoing negotiations with the Iowa Department of
Natural Resources ("IDNR") PCS Nitrogen has administered a voluntary program to
assess, and where necessary, remediate nitrates in groundwater at its now idled
Clinton facility. As part of that program, PCS Nitrogen, with IDNR's approval,
is currently addressing the presence of nitrates by: (i) participating in the
creation of adjacent wetlands; (ii) phytoremediation (planting of trees to
absorb nitrates); (iii) operation of a groundwater recovery trench with
discharge through an existing water effluent outfall; and (iv) restoring
approximately 100 acres of farmland to its natural state of grasses and
woodlands. Although IDNR may require PCS Nitrogen to take further action in the
future, PCS Nitrogen does not currently expect that the cost of such actions or
the current program will have a material adverse effect on the Company's
financial condition or results of operations.

     DSM, which conducts manufacturing operations immediately adjacent to the
Augusta plant, is subject to certain corrective action requirements under its
Resource Conservation and Recovery Act ("RCRA")
                                      I-19
<PAGE>   21

hazardous waste management permit. Pursuant to these requirements, the GEPD
identified a number of solid waste management units on DSM's property, including
several on property formerly leased from DSM by PCS Nitrogen, for assessment and
potential remediation. During 1996, PCS Nitrogen purchased the formerly leased
land and the GEPD required PCS Nitrogen to enter into a corrective action
consent order for the performance of the assessment and remediation actions
which would have been required of DSM with respect to the purchased land under
its RCRA permit. In November 1999, PCS Nitrogen submitted an amendment to its
draft remediation investigation work plan to provide for the assessment of
another area of contamination suspected to be present at a location along the
PCS Nitrogen/DSM property boundary. Although GEPD has yet to approve the plan,
PCS Nitrogen does not expect to incur material costs in connection with its
implementation.

PERMITS AND REGULATORY APPROVALS

     Many of the Company's operations and facilities are required by federal,
provincial, state and local environmental laws to obtain and operate in
compliance with a range of permits and regulatory approvals. Such permits and
approvals typically have to be renewed or reissued periodically. The Company may
also become subject to new laws or regulations that require it to obtain new or
additional permits or approvals. The Company believes that it is in material
compliance with its current permits and regulatory approvals. However, there can
be no assurance that such permits or approvals will issue in the ordinary
course. Further, the terms and conditions of future permits and approvals may be
more stringent and may require increased expenditures on the part of the
Company.

     A significant portion of the Company's phosphate reserves in Aurora, North
Carolina is located in wetlands and, under the U.S. federal Clean Water Act, a
permit must be obtained from the U.S. Army Corps of Engineers (the "Corps")
before mining activity that will disturb the wetlands may occur. As part of the
permit process for PCS Phosphate, the Corps issued a draft Environmental Impact
Statement in January 1994 which was supplemented in May 1995. In 1997, PCS
Phosphate received its required authorizations from the State of North Carolina
and on August 14, 1997, the Corps issued a permit granting approval to mine
certain areas described in the Environmental Impact Statement through 2017. The
permit contains a section on wetlands mitigation approach and methods regarding
wetland impacts associated with mining covered by the permit. The Company has
acquired additional land adjacent to its Aurora, North Carolina facilities for
mitigation purposes. In order to demonstrate the feasibility of such activities,
as of December 31, 1999, the Company had created or restored 2,904 acres of
wetlands.

     On May 6, 1999, the Southern Environmental Law Center ("SELC") and the
Pamlico-Tar River Foundation ("PTRF") gave notice to the EPA and the Department
of the Army of their intent to file a civil action under the citizens suit
provisions of the Clean Water Act. To date, no such action has been filed. The
notice letter asserts that the Army Corps of Engineers failed to comply with
certain provisions of the Clean Water Act when it issued a permit to PCS
Phosphate in August 1997. The notice letter also requests revocation of the
permit. PCS Phosphate believes that the permit was properly issued. PCS
Phosphate intends to monitor the status of this matter and take any steps needed
to protect its ability to continue the operations authorized by the permit.

     In addition to the wetlands permit from the Corps, the Company also needs
additional authorizations from agencies of the State of North Carolina to
continue its mining activities in North Carolina. The Company is required to
have State mining permits that contain bonding and reclamation requirements. The
Company has a State mining permit for the areas presently being mined by the
Company that is effective through 2003, but this permit must be amended
periodically to add additional acreage during this period. The Company also
holds another mining permit from the State for the area of the property that
contains the wetlands covered by the permit issued by the Corps. This State
permit has been renewed until 2005.

     Gypsum is a byproduct of the production of phosphoric acid. Gypsum is
normally placed in above-ground storage areas called gypsum stacks. The gypsum
stacks at the White Springs Facility will continue to be used and when closed
will be covered or capped to the extent required under applicable regulations.
The Florida Phosphogypsum Rule permits the use of existing gypsum stacks until
they reach capacity, if groundwater

                                      I-20
<PAGE>   22

standards are met as of and after March 25, 2001. The Company's management
believes that it will be in compliance with such Rule and as such should be
allowed to continue using its three gypsum stacks for their useful lives of
approximately 35 years; however, until a final determination is made by Florida
environmental authorities, it is not certain how long White Springs will be
allowed to continue using its gypsum stacks beyond the year 2001. A regulatory
prohibition on use of existing stacks would result in a closure/new stack
construction cost currently estimated in excess of $100 million.

     Lands mined by White Springs after July 1, 1975 and unmined lands used in
the mining operations after July 1, 1984 are subject to mandatory reclamation
requirements of the State of Florida. Wetlands must be reclaimed on an
acre-for-acre basis under the rules of the State of Florida Department of
Environmental Protection ("FDEP") unless otherwise provided in, or pursuant to,
a Memorandum of Agreement ("MOA"), dated February 1, 1995, between OxyChem and
FDEP (which agreement was later assigned to the Company). The MOA established
alternate procedures for the Company to follow. The cost of reclamation of
mandatory lands is borne solely by White Springs. The current practice of White
Springs is to return most upland areas to commercial pine plantation, which is
the predominant pre-operation land use. Reclaimed lands include uplands,
wetlands and lakes.

     Land reclamation at White Springs is currently performed pursuant to
federal, state, and local regulatory approvals granted in 1996 and 1997 to
implement the 1995 MOA between OxyChem and FDEP. The MOA provides for mitigation
of mining impacts, particularly impacts to wetlands, to be done through funding
of public acquisition of environmentally sensitive lands in the region. Land
reclamation continues to be done on-site but is undertaken using the alternate
standards of the MOA which do not require the on-site reclamation of wetlands
and which allow for the construction of lands that are expected to be of greater
future utility. The Company's contributions for the land acquisition program
through 1999 totaled $4.2 million.

     White Springs has initiated a process for securing an additional federal
permit and ancillary modifications of state and local regulatory approvals
needed for continuation of mining operations beyond the expiration of its
current federal permit in 2002. The process involves environmental studies of
potential mining areas and evaluation of mine plan and reclamation alternatives.
All affected regulatory authorities, various commenting agencies, and interested
outside parties are participating in the process and completion of the process
is targeted approximately for the conclusion of the year 2000. Applications
covering an interim area to allow orderly continuation of operations were
submitted to the federal and local authorities in 1999. Favorable action on
those applications is anticipated in the first half of 2000. Selection of mine
plan and reclamation alternatives and the results of the environmental studies
could result in changes to reclamation and mitigation practices with higher
costs and changes to mining areas with reserve impacts. The magnitude of such
cost impacts cannot be estimated until the studies and evaluations are
completed. Failure to secure the required approvals for continuation of the
mining operations under any reclamation or mitigation alternative would
negatively affect reserves and costs.

     The local government, with jurisdiction over the White Springs operations,
is Hamilton County, Florida. In 1999, Hamilton County adopted extensive
revisions to its mining and reclamation regulations. The Company participated in
the development of these revisions, which would be applicable to future local
approvals. The revisions principally address information and procedural
requirements and are not expected to materially affect operating conditions or
costs for White Springs.

     The Lima plant discharges wastewater to the Ottawa River under a National
Pollutant Discharge Elimination System permit issued by the Ohio Environmental
Protection Agency ("OEPA"). When the permit was renewed in 1989, the OEPA
initially proposed to impose substantial limitations on certain substances
present in the wastewater, based on concerns over the already impaired quality
of the river water as a result of industrial or municipal discharges. The OEPA
later agreed in an administrative settlement to a five year permit for the Lima
plant with discharge conditions that were more acceptable to the Lima plant's
prior owner, BP Chemicals Inc. The permit expired in 1994 and was
administratively extended and renewed by the OEPA in July 1996, for a shorter
than customary term ending October 31, 1997. In July 1999, the OEPA granted PCS
Nitrogen's permit renewal application for a term ending March 31, 2004, without
substantial additional discharge limitations. Nonetheless, the OEPA may again
seek to impose discharge reductions in the

                                      I-21
<PAGE>   23

future which may require the installation of improved treatment technology, the
cost of which will depend on the limitations ultimately imposed.

POTASH DECOMMISSIONING REGULATIONS

     The environmental regulatory authority in the Province of Saskatchewan has
adopted regulations which require owners or operators of potash mines to produce
decommissioning and reclamation plans including provisions for financial
assurance. These plans, which are subject to the approval of the responsible
Minister, require that a financial assurance plan be established within one year
following approval of the decommissioning and reclamation plans. Pursuant to the
regulations, the Company filed decommissioning plans for each of the Company's
Saskatchewan mines with the responsible Minister in the spring of 1997. In
February 1998, the Company was advised that, although the technical aspects of
the plans were acceptable, the regulatory authority does not accept the schedule
proposed in the plans for decommissioning the waste salt piles. Following
discussions between the provincial potash industry and the regulatory agency, it
was agreed to establish a joint government-industry task force to produce a
mutually acceptable, cost-benefit analysis of the available decommissioning
options. Because of the uncertainty regarding the final nature of the
decommissioning plan, the timing of its implementation and the structure of the
financial assurance mechanism, the Company is unable, at this time, to
accurately estimate the financial implications to the Company.

GOVERNMENT REGULATIONS

     In September 1987, legislation was adopted in Saskatchewan that authorized
the government to control production at potash mines located in the Province of
Saskatchewan. The legislation, which has not taken effect but which can be
brought into effect by proclamation of the Cabinet of Saskatchewan, permits the
Cabinet, and the Potash Resources Board which would be created under such
legislation, to prescribe rates of potash production in Saskatchewan and to
allocate production among individual mines. In determining rates for individual
mines, the Potash Resources Board would take into account a mine's productive
capacity, the rate of production from the mine, the present and future inventory
and stockpile requirements for the mine, the portion of demand for potash that
has been fulfilled by the primary production of potash from the mine and any
additional factors that may be prescribed by regulation. Increases in production
capacity would be subject to the approval of the government of Saskatchewan. The
Company cannot predict at this time if or when the legislation will be
proclaimed or its effects on the Company's financial condition or results of
operations.

EXECUTIVE OFFICERS OF THE COMPANY

     The name, age, period of service and position held for each of the
executive officers of the Company as at March 24, 2000 are as follows:

<TABLE>
<CAPTION>
                                               SERVED
NAME                                     AGE   SINCE    POSITION HELD
----                                     ---   ------   -------------
<S>                                      <C>   <C>      <C>
CHARLES E. CHILDERS....................  67     1987    Chairman of the Board
WILLIAM J. DOYLE.......................  49     1987    President and Chief Executive Officer
WAYNE R. BROWNLEE......................  47     1988    Senior Vice President, Finance and Treasurer
                                                        and Chief Financial Officer
JOHN GUGULYN...........................  64     1987    Senior Vice President, Administration
JOHN L.M. HAMPTON......................  46     1988    Senior Vice President, General Counsel and
                                                        Secretary
BARRY E. HUMPHREYS.....................  56     1976    Senior Vice President, Chief Information
                                                        Officer
BETTY-ANN L. HEGGIE....................  46     1981    Senior Vice President, Corporate Relations
THOMAS J. REGAN........................  55     1995    President, PCS Phosphate
GARTH W. MOORE.........................  51     1982    President, PCS Potash
JAMES F. DIETZ.........................  53     1997    President, PCS Nitrogen
G. DAVID DELANEY.......................  39     1997    President, PCS Sales
DENIS A. SIROIS........................  44     1978    Vice President and Corporate Controller
</TABLE>

                                      I-22
<PAGE>   24

     All of the officers have had the principal occupation indicated for the
previous five years except as follows: Mr. Childers retired as Chief Executive
Officer of the Company on June 30, 1999; Mr. Doyle was President and Chief
Operating Officer of the Company from July 1, 1998 to July 1, 1999; was
President PCS Sales from March 1997 to July 1998 and Executive Vice President,
Potash and Sales, of the Company from 1995 until March 1997. On April 27, 1995,
Mr. Hampton, Mr. Brownlee, and Ms. Heggie were promoted from Vice President to
Senior Vice President. Prior to March 1997, Mr. Moore was Senior Vice President,
Technical Services of the Company and prior to April 1995, he was Vice
President, Technical Services. Mr. Dietz was Vice President, Manufacturing of
Arcadian Corporation from 1993 to March 1997 and Executive Vice President of PCS
Nitrogen from March 1997 to July 1998. Mr. Sirois was Controller of the Company
prior to 1997. Mr. Regan was Executive Vice President of PCS Phosphate from
March 1997 to July 1999, and Vice President, Administration from 1995 to 1997.
Prior to 1995, he was Vice President, Phosphate Production -- Aurora and Vice
President International Marketing & Raw Material Purchasing for Texasgulf. On
July 12, 1999, Mr. Brownlee was appointed to Senior Vice President Finance and
Treasurer and Chief Financial Officer. Mr. Brownlee was Senior Vice President
Expansion and Development from May 1995 to July 1999. On July 12, 1999, Mr.
Humphreys was appointed Senior Vice President and Chief Information Officer. Mr.
Humphreys was Senior Vice President Finance and Treasurer and Chief Financial
Officer from December 1989 to July 1999. Mr. Delaney was appointed President,
PCS Sales on March 24, 2000. Mr. Delaney was Vice President, Industrial Sales of
PCS Sales from March 1997 to March 24, 2000 and was Vice President Agricultural
Sales East for Arcadian Corporation prior to March 1997.

     The terms and conditions of Mr. Childers' employment with the Company are
governed by an employment agreement, the current term of which expires June 30,
2002 and pursuant to which Mr. Childers served as Chairman of the Board and
Chief Executive Officer of the Company until June 30, 1999 and shall continue to
serve as Chairman of the Board and as a special advisor to the Company to June
30, 2002.

ITEM 3.  LEGAL PROCEEDINGS.

AGREEMENT SUSPENDING POTASH DUMPING INVESTIGATION

     In March 1987, the U.S. International Trade Commission made a preliminary
determination that there was a reasonable indication that the U.S. potash
producers had been injured by imports of Canadian potash, assuming that Canadian
potash had been "dumped" into the U.S. market at less than "fair value". On
August 26, 1987, the U.S. Department of Commerce ("Commerce") determined on a
preliminary basis that Canadian potash was, or was likely to be, sold in the
United States at less than "fair value".

     On January 8, 1988, Commerce signed a suspension agreement with all of the
potash producers in Canada, suspending the dumping investigation by Commerce.
The agreement stipulated that each producer's minimum price for potash sold in
the United States was based upon a formula determined by Commerce for each
producer that was designed to limit any dumping by that producer in the future.
Compliance with the agreement was monitored by Commerce.

     In accordance with procedures established by the Uruguay Round Agreements
Act, Commerce and the U.S. International Trade Commission initiated a "sunset"
review of the suspended investigation on April 1, 1999. Since no domestic
interested party filed a notice of intent to participate in the review within
the deadline provided in its regulations, Commerce issued a notice automatically
terminating the suspended dumping investigation effective January 1, 2000. The
suspended investigation and the suspension agreement both terminated on that
date.

CIVIL ANTITRUST COMPLAINTS

     In June 1993, PCS and PCS Sales (Canada) Inc. ("PCS Sales (Canada)") were
served with a complaint relating to a suit filed in the United States District
Court for Minnesota against most North American potash producers, including the
Company. The complaint alleged a conspiracy among the defendants to fix the
price of potash purchased by the plaintiffs as well as potash purchased by the
members of a class of certain purchasers proposed by the plaintiffs. Similar
complaints were filed in the United States District Courts for the Northern
District of Illinois and the Western District of Virginia. On motion of the
                                      I-23
<PAGE>   25

defendants, all of the complaints were transferred and consolidated for
pre-trial purposes in the United States District Court for Minnesota. The
complaint sought treble damages and other relief. PCS and PCS Sales filed a
motion for summary judgment on December 22, 1995. On January 2, 1997, Judge
Richard H. Kyle issued an order granting the defendants' motions for summary
judgment and dismissing the lawsuit. The plaintiffs appealed that order to the
United States Court of Appeals for the Eighth Circuit. On February 17, 2000, the
Eighth Circuit, en banc, affirmed Judge Kyle's summary judgment ruling. The
plaintiffs have indicated that they intend to file a petition requesting the
United States Supreme Court to review the decision of the Eighth Circuit. That
petition must be filed by May 17, 2000.

     Additional complaints were filed in the California and Illinois state
courts on behalf of purported classes of indirect purchasers of potash in those
states. PCS moved to dismiss the California State Court lawsuits for lack of
personal jurisdiction and the court ruled that it does not have personal
jurisdiction over PCS but that it does have personal jurisdiction over PCS
Sales. Following Judge Kyle's summary judgment decision, the California
litigation was stayed and the case remains at an early stage: no merits
discovery has taken place. The Illinois State Court complaint was dismissed for
failure to state a cause of action and that decision is final and not subject to
appeal.

     Insofar as the allegations of wrongdoing in the litigation relate to the
Company, management of the Company, having consulted with legal counsel,
believes that the allegations are without merit, that the Company has valid
legal defenses and that the lawsuit will not have a material adverse effect on
the Company. However, management of the Company cannot predict with certainty
the outcome of the litigation.

FORMER ARCADIAN EXECUTIVE PROCEEDINGS

     On May 7, 1997, J. Douglas Campbell, Alfred L. Williams, Peter H. Kesser,
and David Alyea, former officers of Arcadian, filed lawsuits against the Company
in the United States District Court for the Western District of Tennessee. The
complaints allege that the Company breached employment agreements between
Arcadian and the officers and breached the related assumption agreement among
the Company, PCS Nitrogen, and Arcadian. In addition, Mr. Alyea's complaint
names Charles Childers, John Gugulyn, and John Hampton as additional defendants
and alleges that the defendants interfered with and conspired to interfere with
his employment agreement, and did not accurately state their intentions in
entering into the assumption agreement. The complaints of Mr. Campbell, Mr.
Williams, Mr. Kesser, and Mr. Alyea seek damages in excess of $22.2 million,
$6.2 million, $3.7 million, and $4.2 million, respectively. In addition, on
October 14, 1997, Charles Lance, a former officer of Arcadian Corporation, filed
a lawsuit in the same court against the Company also alleging breaches of his
employment agreement and the related assumption agreement. Mr. Lance seeks
damages in an amount exceeding $3.0 million. Each complaint also seeks certain
additional unspecified damages. On August 11, 1998, the Court ruled that the
Company had assumed the obligations of the employment agreements and that
equitable claims and defenses asserted against the executives for breaches of
fiduciary duties, corporate waste, and self-dealing should be asserted by PCS
Nitrogen in the state court action described below. Trial with respect to the
claims of Mr. Campbell, Mr. Williams and Mr. Kesser commenced on August 17, 1998
and concluded on August 25, 1998. On December 1, 1998 the court entered
judgments in the amounts of $12.7 million, $3.2 million, and $2.6 million in
favor of Mr. Campbell, Mr. Williams and Mr. Kesser, subject to additional
amounts sufficient to offset the impact of certain excise taxes, if applicable.
These judgments have been appealed to the United States Court of Appeals for the
Sixth Circuit, where oral argument was heard on March 9, 2000. The Company has
settled the claim of Mr. Alyea for $700,000 and $50,000 of attorneys fees
(subject to the application for additional fees) and the claim of Mr. Lance for
a total amount of $600,000. The District Court, on August 13, 1999, awarded
plaintiffs a total of $2,410,254 for legal expenses.

     On September 15, 1997, the Company and PCS Nitrogen filed an action in the
Circuit Court of Tennessee for the Thirtieth Judicial District at Memphis
against J. Douglas Campbell, Peter H. Kesser, Alfred L. Williams, Charles W.
Lance, Jr., and David L. Alyea, for declaratory relief and damages. The Company
and PCS Nitrogen alleged that the defendants, all former executives of Arcadian,
committed breaches of their fiduciary duties in the negotiation of, obtaining
approval for, and execution of the employment agreements each of them had with
Arcadian. In addition, the Company and PCS Nitrogen also
                                      I-24
<PAGE>   26

sought a declaratory judgment with respect to the unenforceability of the
employment agreements. On October 14, 1997, the defendants removed this action
from the Circuit Court of Tennessee to the United States District Court for the
Western District of Tennessee. On October 21, 1997, the five defendants filed
counterclaims: (i) under the Employee Retirement Income Security Act of 1974, as
amended ("ERISA"), against PCS Nitrogen, (ii) alleging that the Company and PCS
Nitrogen unlawfully interfered with their attainment of benefits under their
employment agreements, and (iii) incorporating by reference all claims asserted
in their individually filed complaints. The damages sought by the defendants in
these counterclaims appear substantially equivalent to the damages sought in
their individually filed suits as plaintiffs. On July 20, 1998 the federal court
dismissed all of the former executives' claims under ERISA and remanded the case
to state court, where it remains pending. Pursuant to the settlements with Mr.
Alyea and Mr. Lance, the claims and counterclaims as they concern these
individuals have been non-suited.

     Management of the Company, having consulted with legal counsel, believes
that the lawsuits will not have a material adverse effect on the Company's
financial condition or results of operations.

GEISMAR FACILITY INVESTIGATION

     On May 11 and May 12, 1999, representatives of the EPA, Federal Bureau of
Investigation, and other state and local agencies ("governmental agencies")
executed a search warrant issued by the United States District Court for the
Middle District of Louisiana on the Company's Geismar facility ("Geismar
Facility") in connection with a grand jury investigation. In executing the
search warrant, the governmental agencies seized documents and electronic media,
performed environmental sampling, and interviewed Geismar Facility employees and
contract employees. In addition, the governmental agencies have contacted former
Geismar Facility employees in connection with the investigation. The Company has
also been served with grand jury subpoenas requesting documents and other
information from the Geismar Facility and PCS Nitrogen's headquarters in
Memphis, Tennessee. The grand jury investigation is continuing. The Company is
also conducting its own internal investigation. The Company cannot predict at
this time what may result from the governments' investigation or whether any
such result would have a material adverse effect on the Company.

LAKELAND, FLORIDA PROCEEDING

     On September 23, 1999, an action was served on PCS Joint Venture and eight
other defendants on behalf of a class of persons living in the vicinity of the
site who claim to have suffered damages as a result of releases from the PCS
Joint Venture facility in Lakeland, Florida and other area properties (the
"Landia Site"). PCS Joint Venture intends to defend itself vigorously in this
action, while also continuing to work to assess and evaluate the nature and
extent of the impacts at the site.

ENVIRONMENTAL PROCEEDINGS

     For a description of certain environmental proceedings involving the
Company, see "Environmental Matters".

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

     Not applicable.

                                      I-25
<PAGE>   27

                                    PART II

ITEM 5.  MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS.

     The information under "Common Share Prices and Volumes", "Shareholder
Information -- Ownership" and "10-Year Report" in the registrant's 1999 Annual
Report is incorporated herein by reference.

     Dividends paid to U.S. holders of Common Shares, who do not use the shares
in carrying on a business in Canada, will be subject to a Canadian withholding
tax under the Income Tax Act. Under the Canada-U.S. Income Tax Convention (1980)
(the "Convention"), the rate of withholding is generally reduced to 15 percent.
Subject to certain limitations, the Canadian withholding tax will be treated as
a foreign income tax that can generally be claimed as a deduction from income or
as a credit against the U.S. income tax liability of the holder. Holders will
generally not be subject to tax under the Income Tax Act with respect to any
gain realized from a disposition of Common Shares.

ITEM 6.  SELECTED FINANCIAL DATA.

     The information under "10-Year Report" in the registrant's 1999 Annual
Report is incorporated herein by reference.

ITEM 7.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS.

     The information under "Management's Discussion and Analysis of Financial
Condition and Results of Operations" in the registrant's 1999 Annual Report is
incorporated herein by reference.

ITEM 8.  FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA.

     The Consolidated Financial Statements contained in the registrant's 1999
Annual Report are incorporated herein by reference.

ITEM 9.  CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
FINANCIAL DISCLOSURE.

     Not applicable.

                                      II-1
<PAGE>   28

                                    PART III

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT.

     The information under "Election of Directors" in the 2000 Proxy Circular is
incorporated herein by reference. Information concerning executive officers is
set forth under "Executive Officers of the Company" in Part I.

ITEM 11.  EXECUTIVE COMPENSATION.

     The information under "Executive Compensation" in the 2000 Proxy Circular
is incorporated herein by reference.

ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT.

     The information under "Ownership of Shares" and "Election of Directors" in
the 2000 Proxy Circular is incorporated herein by reference.

ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS.

     The information under "Election of Directors" and "Executive Compensation"
in the 2000 Proxy Circular is incorporated herein by reference.

                                      III-1
<PAGE>   29

                                    PART IV

ITEM 14.  EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K.

(a) List of Documents Filed as Part of this Report

1.   Consolidated Financial Statements in Annual Report

<TABLE>
<S>                                                           <C>
Auditors' Report............................................     44
Consolidated Statements of Financial Position...............     45
Consolidated Statements of Income and Retained Earnings.....     46
Consolidated Statements of Cash Flow........................     47
Notes to the Consolidated Financial Statements..............  48-63
</TABLE>

2.   Schedules

     All Schedules are omitted because the required information is inapplicable
or it is presented in the Consolidated Financial Statements.

3.   Exhibits

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                     DESCRIPTION OF DOCUMENT
-------                    -----------------------
<C>      <S>
  2      Agreement and Plan of Merger dated September 2, 1996, as
         amended, by and among the registrant, Arcadian Corporation
         and PCS Nitrogen, Inc., incorporated by reference to Exhibit
         2(a) to Amendment Number 2 to the registrant's Form S-4
         (File No. 333-17841).
 3(a)    Restated Articles of Incorporation of the registrant dated
         October 31, 1989, as amended May 11, 1995, incorporated by
         reference to Exhibit 3(i) to the registrant's report on Form
         10-K for the year ended December 31, 1995 (the "1995 Form
         10-K").
 3(b)    Bylaws of the registrant dated March 2, 1995, incorporated
         by reference to Exhibit 3(ii) to the 1995 Form 10-K.
 4(a)    Term Credit Agreement between The Bank of Nova Scotia and
         other financial institutions and the registrant dated
         October 4, 1996, incorporated by reference to Exhibit 4(b)
         to the registrant's Form S-4 (File No. 333-17841).
 4(b)    First Amending Agreement to Term Credit Agreement between
         The Bank of Nova Scotia and other financial institutions and
         the registrant dated November 6, 1997, incorporated by
         reference to Exhibit 4(b) to the registrant's report on Form
         10-K for the year ended December 31, 1997 (the "1997 Form
         10-K").
 4(c)    Second Amending Agreement to Term Credit Agreement between
         The Bank of Nova Scotia and other financial institutions and
         the registrant dated December 15, 1997, incorporated by
         reference to Exhibit 4(c) to the 1997 Form 10-K.
 4(d)    Third Amending Agreement to Term Credit Agreement between
         The Bank of Nova Scotia and other financial institutions and
         the registrant dated October 2, 1998, incorporated by
         reference to Exhibit 4(d) to the registrant's report on Form
         10-Q for the quarterly period ended September 30, 1998.
 4(e)    Fourth Amending Agreement to Term Credit Agreement between
         The Bank of Nova Scotia and other financial institutions and
         the registrant dated September 30, 1999, incorporated by
         reference to exhibit 4(e) to the registrant's report on Form
         10-Q for the quarterly period ended September 30, 1999 (the
         "Third Quarter 1999 Form 10-Q").
 4(f)    Indenture dated as of June 16, 1997, between the registrant
         and The Bank of Nova Scotia Trust Company of New York,
         incorporated by reference to Exhibit 4(a) to the
         registrant's report on Form 8-K dated June 18, 1997.
</TABLE>

                                      IV-1
<PAGE>   30

     The registrant hereby undertakes to file with the Securities and Exchange
Commission, upon request, copies of any constituent instruments defining the
rights of holders of long-term debt of the registrant or its subsidiaries that
have not been filed herewith because the amounts represented thereby are less
than 10% of the total assets of the registrant and its subsidiaries on a
consolidated basis.

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                     DESCRIPTION OF DOCUMENT
-------                    -----------------------
<S>      <C>
10(a)    Suspension Agreement concerning Potassium Chloride from
         Canada dated January 7, 1988, among U.S. Department of
         Commerce, the registrant, International Minerals and
         Chemical (Canada) Limited, Noranda, Inc. (Central Canada
         Potash Co.), Potash Company of America, a Division of Rio
         Algom Limited, S & P Canada, II (Kalium Chemicals), Cominco
         Ltd., Potash Company of Canada Limited, Agent for
         Denison-Potacan Potash Co. and Saskterra Fertilizers Ltd.,
         incorporated by reference to Exhibit 10(a) to the
         registrant's registration statement on Form F-1 (File No.
         33-31303) (the "F-1 Registration Statement").
10(b)    Sixth Voting Agreement dated April 22, 1978, between Central
         Canada Potash, Division of Noranda, Inc., Cominco Ltd.,
         International Minerals and Chemical Corporation (Canada)
         Limited, PCS Sales and Texasgulf Inc., incorporated by
         reference to Exhibit 10(f) to the F-1 Registration
         Statement.
10(c)    Canpotex Limited Shareholders Seventh Memorandum of
         Agreement effective April 21, 1978, between Central Canada
         Potash, Division of Noranda Inc., Cominco Ltd.,
         International Minerals and Chemical Corporation (Canada)
         Limited, PCS Sales, Texasgulf Inc. and Canpotex Limited as
         amended by Canpotex S & P amending agreement dated November
         4, 1987, incorporated by reference to Exhibit 10(g) to the
         F-1 Registration Statement.
10(d)    Producer Agreement dated April 21, 1978, between Canpotex
         Limited and PCS Sales, incorporated by reference to Exhibit
         10(h) to the F-1 Registration Statement.
10(e)    Agreement of Limited Partnership of Arcadian Fertilizer,
         L.P. dated as of March 3, 1992 (form), and the related
         Certificate of Limited Partnership of Arcadian Fertilizer,
         L.P., filed with the Secretary of State of the State of
         Delaware on March 3, 1992 (incorporated by reference to
         Exhibits 3.1 and 3.2 to Arcadian Partners L.P.'s
         Registration Statement on Form S-1 (File No. 33-45828)).
10(f)    Amendment to Agreement of Limited Partnership of Arcadian
         Fertilizer, L.P. and related Certificates of Limited
         Partnership of Arcadian Fertilizer, L.P. filed with the
         Secretary of State of the State of Delaware on March 6, 1997
         and November 26, 1997, incorporated by reference to Exhibit
         10(f) to the registrant's report on Form 10-K for the year
         ended December 31, 1998 (the "1998 Form 10-K").
10(g)    Geismar Complex Services Agreement dated June 4, 1984,
         between Honeywell International, Inc. and Arcadian
         Corporation, incorporated by reference to Exhibit 10.4 to
         Arcadian Corporation's Registration Statement on Form S-1
         (File No. 33-34357).
10(h)    Canpotex/PCS Amending Agreement, dated with effect October
         1, 1992, incorporated by reference to Exhibit 10(f) to the
         1995 Form 10-K.
10(i)    Canpotex PCA Collateral Withdrawing/PCS Amending Agreement,
         dated with effect October 7, 1993, incorporated by reference
         to Exhibit 10(g) to the 1995 Form 10-K.
10(j)    Esterhazy Restated Mining and Processing Agreement dated
         January 31, 1978, between International Minerals and
         Chemical Corporation (Canada) Limited and the registrant's
         predecessor, incorporated by reference to Exhibit 10(e) to
         the F-1 Registration Statement.
10(k)    Agreement dated December 21, 1990, between International
         Minerals & Chemical Corporation (Canada) Limited and the
         registrant, amending the Esterhazy Restated Mining and
         Processing Agreement dated January 31, 1978, incorporated by
         reference to Exhibit 10(p) to the registrant's report on
         Form 10-K for the year ended December 31, 1990.
</TABLE>

                                      IV-2
<PAGE>   31

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                     DESCRIPTION OF DOCUMENT
-------                    -----------------------
<S>      <C>
10(l)    Agreement effective August 27, 1998, between International
         Minerals & Chemical (Canada) Global Limited and the
         registrant, amending the Esterhazy Restated Mining and
         Processing Agreement dated January 31, 1978 (as amended),
         incorporated by reference to Exhibit 10(l) to the 1998 Form
         10-K.
10(m)    Agreement effective August 31, 1998, among International
         Minerals & Chemical (Canada) Global Limited, International
         Minerals & Chemical (Canada) Limited Partnership and the
         registrant assigning the interest in the Esterhazy Restated
         Mining and Processing Agreement dated January 31, 1978 (as
         amended) held by International Minerals & Chemical (Canada)
         Global Limited to International Minerals & Chemical (Canada)
         Limited Partnership, incorporated by reference to Exhibit
         10(m) to the 1998 Form 10-K.
10(n)    Operating Agreement dated May 11, 1993, between BP Chemicals
         Inc. and Arcadian Ohio, L.P., as amended by the First
         Amendment to the Operating Agreement dated as of November
         20, 1995, between BP Chemicals Inc. and Arcadian Ohio, L.P.
         ("First Amendment"), incorporated by reference to Exhibit
         10.2 to Arcadian Partners L.P.'s current report on Form 8-K
         for the report event dated May 11, 1993, except for the
         First Amendment which is incorporated by reference to
         Arcadian Corporation's report on Form 10-K for the year
         ended December 31, 1995.
10(o)    Second Amendment to Operating Agreement between BP
         Chemicals, Inc. and Arcadian Ohio, L.P., dated as of
         November 25, 1996, incorporated by reference to Exhibit
         10(k) to the 1997 Form 10-K.
10(p)    Manufacturing Support Agreement dated May 11, 1993, between
         BP Chemicals Inc. and Arcadian Ohio, L.P., incorporated by
         reference to Exhibit 10.3 to Arcadian Partners L.P.'s
         current report on Form 8-K for the report event dated May
         11, 1993.
10(q)    First Amendment to Manufacturing Support Agreement between
         BP Chemicals, Inc. and Arcadian Ohio, L.P., dated as of
         November 25, 1996, incorporated by reference to Exhibit
         10(l) to the 1997 Form 10-K.
10(r)    Amended and Restated Agreement for Lease dated as of May 16,
         1997, between Trinidad Ammonia Company, Limited Partnership,
         and PCS Nitrogen Fertilizer, L.P., incorporated by reference
         to Exhibit 10(n) to the registrant's report on Form 10-Q for
         the quarterly period ended June 30, 1997 (the "Second
         Quarter 1997 Form 10-Q").
10(s)    Amended and Restated Lease Agreement dated as of May 16,
         1997, between Trinidad Ammonia Company, Limited Partnership,
         and PCS Nitrogen Fertilizer, L.P., incorporated by reference
         to Exhibit 10(o) to the Second Quarter 1997 Form 10-Q.
10(t)    Amended and Restated Agreement for Lease dated as of May 16,
         1997, between Nitrogen Leasing Company, Limited Partnership,
         and PCS Nitrogen Fertilizer, L.P., incorporated by reference
         to Exhibit 10(p) to the Second Quarter 1997 Form 10-Q.
10(u)    Amended and Restated Lease Agreement dated as of May 16,
         1997, between Nitrogen Leasing Company, Limited Partnership,
         and PCS Nitrogen Fertilizer, L.P., incorporated by reference
         to Exhibit 10(q) to the Second Quarter 1997 Form 10-Q.
10(v)    Amended and Restated Purchase Option Agreement dated as of
         May 16, 1997, between Nitrogen Leasing Company, Limited
         Partnership, and PCS Nitrogen Fertilizer Operations, Inc.,
         incorporated by reference to Exhibit 10(r) to the Second
         Quarter 1997 Form 10-Q.
10(w)    Amended and Restated Purchase Option Agreement dated as of
         May 16, 1997, between Trinidad Ammonia Company, Limited
         Partnership and PCS Nitrogen Fertilizer Operations, Inc.,
         incorporated by reference to Exhibit 10(s) to the Second
         Quarter 1997 Form 10-Q.
10(x)    Agreement dated January 1, 1997 between the registrant and
         Charles E. Childers, incorporated by reference to Exhibit
         10(s) to the 1997 Form 10-K.
</TABLE>

                                      IV-3
<PAGE>   32

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                     DESCRIPTION OF DOCUMENT
-------                    -----------------------
<S>      <C>
10(y)    Potash Corporation of Saskatchewan Inc. Stock Option Plan -
         Directors, as amended November 3, 1999, incorporated by
         reference to Exhibit 10(y) to the Third Quarter 1999 Form
         10-Q.
10(z)    Potash Corporation of Saskatchewan Inc. Stock Option Plan -
         Officers and Key Employees, as amended November 3, 1999,
         incorporated by reference to Exhibit 10(z) to the Third
         Quarter 1999 Form 10-Q.
10(aa)   Short-Term Incentive Plan of the registrant, as amended May
         7, 1997, incorporated by reference to Exhibit 10(w) to the
         Second Quarter 1997 Form 10-Q.
10(bb)   Long-Term Incentive Plan of the registrant, as amended May
         7, 1997, incorporated by reference to Exhibit 10(x) to the
         Second Quarter 1997 Form 10-Q.
10(cc)   Resolution and Forms of Agreement for Supplemental
         Retirement Income Plan, for officers and key employees of
         the registrant, incorporated by reference to Exhibit 10(o)
         to the 1995 Form 10-K.
10(dd)   Forms of Agreement dated December 30, 1994, between the
         registrant and certain officers of the registrant,
         concerning a change in control of the registrant,
         incorporated by reference to Exhibit 10(p) to the 1995 Form
         10-K.
10(ee)   Form of Agreement of Indemnification dated August 8, 1995,
         between the registrant and certain officers and directors of
         the registrant, incorporated by reference to Exhibit 10(q)
         to the 1995 Form 10-K.
10(ff)   Supplemental Retirement Benefits Plan, for eligible
         employees of PCS Phosphate Company, Inc., incorporated by
         reference to Exhibit 10(s) to the 1995 Form 10-K.
10(gg)   Second Amended and Restated Membership Agreement dated
         January 1, 1995, among Phosphate Chemicals Export
         Association, Inc. and members of such association, including
         Texasgulf Inc., incorporated by reference to Exhibit 10(t)
         to the 1995 Form 10-K.
10(hh)   International Agency Agreement dated January 1, 1995,
         between Phosphate Chemicals Export Association, Inc. and
         Texasgulf Inc. establishing Texasgulf Inc. as exclusive
         marketing agent for such association's wet phosphatic
         materials, incorporated by reference to Exhibit 10(u) to the
         1995 Form 10-K.
10(ii)   General Partnership Agreement forming Albright & Wilson
         Company, dated July 29, 1988 and amended January 31, 1995,
         between Texasgulf Inc. and Albright & Wilson Americas Inc.,
         incorporated by reference to Exhibit 10(v) to the 1995 Form
         10-K.
10(jj)   Amendment to the Albright & Wilson Company General
         Partnership agreement dated March 23, 2000.
10(kk)   Royalty Agreement dated October 7, 1993, by and between the
         registrant and Rio Algom Limited, incorporated by reference
         to Exhibit 10(x) to the 1995 Form 10-K.
10(ll)   Amending Resolution and revised forms of agreement regarding
         Supplemental Retirement Income Plan of the registrant,
         incorporated by reference to Exhibit 10(x) to the
         registrant's report on Form 10-Q for the quarterly period
         ended June 30, 1996.
10(mm)   Shareholder Rights Agreement as amended and restated on
         March 2, 1998, incorporated by reference to Schedule B to
         the registrant's proxy circular for the annual and special
         meeting of shareholders held on May 7, 1998.
11       Statement re Computation of Per Share Earnings.
13       1999 Annual Report
21       Subsidiaries of the Registrant
23       Consent of Deloitte & Touche LLP.
27       Financial Data Schedule.
</TABLE>

                                      IV-4
<PAGE>   33

(b) Reports on Form 8-K

     On October 22, 1999, the registrant filed a report on Form 8-K regarding a
press release issued on October 21, 1999 announcing certain one-time corporate
charges and plant closures.

Copies of Exhibits to the Form 10-K may be obtained upon request from the
Corporate Secretary, Potash Corporation of Saskatchewan Inc., Suite 500, 122
First Avenue South, Saskatoon, Saskatchewan S7K 7G3, Canada. The Company
reserves the right to recover its reasonable expenses in providing copies of the
Exhibits, such expenses not to exceed $.25 per page.
                                      IV-5
<PAGE>   34

                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

                                     POTASH CORPORATION OF SASKATCHEWAN INC.

                                     By: /s/ WILLIAM J. DOYLE
                                       -----------------------------------------
                                       William J. Doyle
                                       President & Chief Executive Officer
                                       March 27, 2000

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
registrant and in the capacities and on the dates indicated.

<TABLE>
<CAPTION>
                SIGNATURE                                     TITLE                          DATE
                ---------                                     -----                          ----
<C>                                         <S>                                         <C>
         /s/ CHARLES E. CHILDERS            Chairman of the Board                       March 27, 2000
------------------------------------------
           Charles E. Childers

          /s/ WAYNE R. BROWNLEE             Senior Vice President, Finance and          March 27, 2000
------------------------------------------  Treasurer and Chief Financial Officer
            Wayne R. Brownlee

           /s/ WILLIAM J. DOYLE             President and Chief Executive Officer       March 27, 2000
------------------------------------------
             William J. Doyle

          /s/ ISABEL B. ANDERSON            Director                                    March 27, 2000
------------------------------------------
            Isabel B. Anderson

          /s/ DOUGLAS J. BOURNE             Director                                    March 27, 2000
------------------------------------------
            Douglas J. Bourne

     /s/ HON. WILLARD Z. ESTEY, Q.C.        Director                                    March 27, 2000
------------------------------------------
        Hon. Willard Z. Estey, Q.C

            /s/ DALLAS J. HOWE              Director                                    March 27, 2000
------------------------------------------
              Dallas J. Howe

          /s/ DONALD E. PHILLIPS            Director                                    March 27, 2000
------------------------------------------
            Donald E. Phillips

          /s/ PAUL J. SCHOENHALS            Director                                    March 27, 2000
------------------------------------------
            Paul J. Schoenhals
</TABLE>
<PAGE>   35

<TABLE>
<CAPTION>
                SIGNATURE                                     TITLE                          DATE
                ---------                                     -----                          ----
<C>                                         <S>                                         <C>
           /s/ DARYL K. SEAMAN              Director                                    March 27, 2000
------------------------------------------
             Daryl K. Seaman

      /s/ E. ROBERT STROMBERG, Q.C.         Director                                    March 27, 2000
------------------------------------------
         E. Robert Stromberg, Q.C

             /s/ JACK G. VICQ               Director                                    March 27, 2000
------------------------------------------
               Jack G. Vicq

          /s/ BARRIE A. WIGMORE             Director                                    March 27, 2000
------------------------------------------
            Barrie A. Wigmore

             /s/ PAUL S. WISE               Director                                    March 27, 2000
------------------------------------------
               Paul S. Wise

           /s/ THOMAS J. WRIGHT             Director                                    March 27, 2000
------------------------------------------
             Thomas J. Wright
</TABLE>
<PAGE>   36

<TABLE>
<CAPTION>
                               EXHIBIT INDEX
                               -------------
<C>     <S>
  2     Agreement and Plan of Merger dated September 2, 1996, as
        amended, by and among the registrant, Arcadian Corporation
        and PCS Nitrogen, Inc., incorporated by reference to Exhibit
        2(a) to Amendment Number 2 to the registrant's Form S-4
        (File No. 333-17841).
 3(a)   Restated Articles of Incorporation of the registrant dated
        October 31, 1989, as amended May 11, 1995, incorporated by
        reference to Exhibit 3(i) to the registrant's report on Form
        10-K for the year ended December 31, 1995 (the "1995 Form
        10-K").
 3(b)   Bylaws of the registrant dated March 2, 1995, incorporated
        by reference to Exhibit 3(ii) to the 1995 Form 10-K.
 4(a)   Term Credit Agreement between The Bank of Nova Scotia and
        other financial institutions and the registrant dated
        October 4, 1996, incorporated by reference to Exhibit 4(b)
        to the registrant's Form S-4 (File No. 333-17841).
 4(b)   First Amending Agreement to Term Credit Agreement between
        The Bank of Nova Scotia and other financial institutions and
        the registrant dated November 6, 1997, incorporated by
        reference to Exhibit 4(b) to the registrant's report on Form
        10-K for the year ended December 31, 1997 (the "1997 Form
        10-K").
 4(c)   Second Amending Agreement to Term Credit Agreement between
        The Bank of Nova Scotia and other financial institutions and
        the registrant dated December 15, 1997, incorporated by
        reference to Exhibit 4(c) to the 1997 Form 10-K.
 4(d)   Third Amending Agreement to Term Credit Agreement between
        The Bank of Nova Scotia and other financial institutions and
        the registrant dated October 2, 1998, incorporated by
        reference to Exhibit 4(d) to the registrant's report on Form
        10-Q for the quarterly period ended September 30, 1998.
 4(e)   Fourth Amending Agreement to Term Credit Agreement between
        The Bank of Nova Scotia and other financial institutions and
        the registrant dated September 30, 1999, incorporated by
        reference to exhibit 4(e) to the registrant's report on Form
        10-Q for the quarterly period ended September 30, 1999 (the
        "Third Quarter 1999 Form 10-Q").
 4(f)   Indenture dated as of June 16, 1997, between the registrant
        and The Bank of Nova Scotia Trust Company of New York,
        incorporated by reference to Exhibit 4(a) to the
        registrant's report on Form 8-K dated June 18, 1997.
</TABLE>
<PAGE>   37

<TABLE>
<CAPTION>
                               EXHIBIT INDEX
                               -------------
<S>     <C>
10(a)   Suspension Agreement concerning Potassium Chloride from
        Canada dated January 7, 1988, among U.S. Department of
        Commerce, the registrant, International Minerals and
        Chemical (Canada) Limited, Noranda, Inc. (Central Canada
        Potash Co.), Potash Company of America, a Division of Rio
        Algom Limited, S & P Canada, II (Kalium Chemicals), Cominco
        Ltd., Potash Company of Canada Limited, Agent for
        Denison-Potacan Potash Co. and Saskterra Fertilizers Ltd.,
        incorporated by reference to Exhibit 10(a) to the
        registrant's registration statement on Form F-1 (File No.
        33-31303) (the "F-1 Registration Statement").
10(b)   Sixth Voting Agreement dated April 22, 1978, between Central
        Canada Potash, Division of Noranda, Inc., Cominco Ltd.,
        International Minerals and Chemical Corporation (Canada)
        Limited, PCS Sales and Texasgulf Inc., incorporated by
        reference to Exhibit 10(f) to the F-1 Registration
        Statement.
10(c)   Canpotex Limited Shareholders Seventh Memorandum of
        Agreement effective April 21, 1978, between Central Canada
        Potash, Division of Noranda Inc., Cominco Ltd.,
        International Minerals and Chemical Corporation (Canada)
        Limited, PCS Sales, Texasgulf Inc. and Canpotex Limited as
        amended by Canpotex S & P amending agreement dated November
        4, 1987, incorporated by reference to Exhibit 10(g) to the
        F-1 Registration Statement.
10(d)   Producer Agreement dated April 21, 1978, between Canpotex
        Limited and PCS Sales, incorporated by reference to Exhibit
        10(h) to the F-1 Registration Statement.
10(e)   Agreement of Limited Partnership of Arcadian Fertilizer,
        L.P. dated as of March 3, 1992 (form), and the related
        Certificate of Limited Partnership of Arcadian Fertilizer,
        L.P., filed with the Secretary of State of the State of
        Delaware on March 3, 1992 (incorporated by reference to
        Exhibits 3.1 and 3.2 to Arcadian Partners L.P.'s
        Registration Statement on Form S-1 (File No. 33-45828)).
10(f)   Amendment to Agreement of Limited Partnership of Arcadian
        Fertilizer, L.P. and related Certificates of Limited
        Partnership of Arcadian Fertilizer, L.P. filed with the
        Secretary of State of the State of Delaware on March 6, 1997
        and November 26, 1997, incorporated by reference to Exhibit
        10(f) to the registrant's report on Form 10-K for the year
        ended December 31, 1998 (the "1998 Form 10-K").
10(g)   Geismar Complex Services Agreement dated June 4, 1984,
        between Honeywell International, Inc. and Arcadian
        Corporation, incorporated by reference to Exhibit 10.4 to
        Arcadian Corporation's Registration Statement on Form S-1
        (File No. 33-34357).
10(h)   Canpotex/PCS Amending Agreement, dated with effect October
        1, 1992, incorporated by reference to Exhibit 10(f) to the
        1995 Form 10-K.
10(i)   Canpotex PCA Collateral Withdrawing/PCS Amending Agreement,
        dated with effect October 7, 1993, incorporated by reference
        to Exhibit 10(g) to the 1995 Form 10-K.
10(j)   Esterhazy Restated Mining and Processing Agreement dated
        January 31, 1978, between International Minerals and
        Chemical Corporation (Canada) Limited and the registrant's
        predecessor, incorporated by reference to Exhibit 10(e) to
        the F-1 Registration Statement.
10(k)   Agreement dated December 21, 1990, between International
        Minerals & Chemical Corporation (Canada) Limited and the
        registrant, amending the Esterhazy Restated Mining and
        Processing Agreement dated January 31, 1978, incorporated by
        reference to Exhibit 10(p) to the registrant's report on
        Form 10-K for the year ended December 31, 1990.
</TABLE>
<PAGE>   38

<TABLE>
<CAPTION>
                               EXHIBIT INDEX
                               -------------
<S>     <C>
10(l)   Agreement effective August 27, 1998, between International
        Minerals & Chemical (Canada) Global Limited and the
        registrant, amending the Esterhazy Restated Mining and
        Processing Agreement dated January 31, 1978 (as amended),
        incorporated by reference to Exhibit 10(l) to the 1998 Form
        10-K.
10(m)   Agreement effective August 31, 1998, among International
        Minerals & Chemical (Canada) Global Limited, International
        Minerals & Chemical (Canada) Limited Partnership and the
        registrant assigning the interest in the Esterhazy Restated
        Mining and Processing Agreement dated January 31, 1978 (as
        amended) held by International Minerals & Chemical (Canada)
        Global Limited to International Minerals & Chemical (Canada)
        Limited Partnership, incorporated by reference to Exhibit
        10(m) to the 1998 Form 10-K.
10(n)   Operating Agreement dated May 11, 1993, between BP Chemicals
        Inc. and Arcadian Ohio, L.P., as amended by the First
        Amendment to the Operating Agreement dated as of November
        20, 1995, between BP Chemicals Inc. and Arcadian Ohio, L.P.
        ("First Amendment"), incorporated by reference to Exhibit
        10.2 to Arcadian Partners L.P.'s current report on Form 8-K
        for the report event dated May 11, 1993, except for the
        First Amendment which is incorporated by reference to
        Arcadian Corporation's report on Form 10-K for the year
        ended December 31, 1995.
10(o)   Second Amendment to Operating Agreement between BP
        Chemicals, Inc. and Arcadian Ohio, L.P., dated as of
        November 25, 1996, incorporated by reference to Exhibit
        10(k) to the 1997 Form 10-K.
10(p)   Manufacturing Support Agreement dated May 11, 1993, between
        BP Chemicals Inc. and Arcadian Ohio, L.P., incorporated by
        reference to Exhibit 10.3 to Arcadian Partners L.P.'s
        current report on Form 8-K for the report event dated May
        11, 1993.
10(q)   First Amendment to Manufacturing Support Agreement between
        BP Chemicals, Inc. and Arcadian Ohio, L.P., dated as of
        November 25, 1996, incorporated by reference to Exhibit
        10(l) to the 1997 Form 10-K.
10(r)   Amended and Restated Agreement for Lease dated as of May 16,
        1997, between Trinidad Ammonia Company, Limited Partnership,
        and PCS Nitrogen Fertilizer, L.P., incorporated by reference
        to Exhibit 10(n) to the registrant's report on Form 10-Q for
        the quarterly period ended June 30, 1997 (the "Second
        Quarter 1997 Form 10-Q").
10(s)   Amended and Restated Lease Agreement dated as of May 16,
        1997, between Trinidad Ammonia Company, Limited Partnership,
        and PCS Nitrogen Fertilizer, L.P., incorporated by reference
        to Exhibit 10(o) to the Second Quarter 1997 Form 10-Q.
10(t)   Amended and Restated Agreement for Lease dated as of May 16,
        1997, between Nitrogen Leasing Company, Limited Partnership,
        and PCS Nitrogen Fertilizer, L.P., incorporated by reference
        to Exhibit 10(p) to the Second Quarter 1997 Form 10-Q.
10(u)   Amended and Restated Lease Agreement dated as of May 16,
        1997, between Nitrogen Leasing Company, Limited Partnership,
        and PCS Nitrogen Fertilizer, L.P., incorporated by reference
        to Exhibit 10(q) to the Second Quarter 1997 Form 10-Q.
10(v)   Amended and Restated Purchase Option Agreement dated as of
        May 16, 1997, between Nitrogen Leasing Company, Limited
        Partnership, and PCS Nitrogen Fertilizer Operations, Inc.,
        incorporated by reference to Exhibit 10(r) to the Second
        Quarter 1997 Form 10-Q.
10(w)   Amended and Restated Purchase Option Agreement dated as of
        May 16, 1997, between Trinidad Ammonia Company, Limited
        Partnership and PCS Nitrogen Fertilizer Operations, Inc.,
        incorporated by reference to Exhibit 10(s) to the Second
        Quarter 1997 Form 10-Q.
10(x)   Agreement dated January 1, 1997 between the registrant and
        Charles E. Childers, incorporated by reference to Exhibit
        10(s) to the 1997 Form 10-K.
</TABLE>
<PAGE>   39

<TABLE>
<CAPTION>
                               EXHIBIT INDEX
                               -------------
<S>     <C>
10(y)   Potash Corporation of Saskatchewan Inc. Stock Option Plan -
        Directors, as amended November 3, 1999, incorporated by
        reference to Exhibit 10(y) to the Third Quarter 1999 Form
        10-Q.
10(z)   Potash Corporation of Saskatchewan Inc. Stock Option Plan -
        Officers and Key Employees, as amended November 3, 1999,
        incorporated by reference to Exhibit 10(z) to the Third
        Quarter 1999 Form 10-Q.
10(aa)  Short-Term Incentive Plan of the registrant, as amended May
        7, 1997, incorporated by reference to Exhibit 10(w) to the
        Second Quarter 1997 Form 10-Q.
10(bb)  Long-Term Incentive Plan of the registrant, as amended May
        7, 1997, incorporated by reference to Exhibit 10(x) to the
        Second Quarter 1997 Form 10-Q.
10(cc)  Resolution and Forms of Agreement for Supplemental
        Retirement Income Plan, for officers and key employees of
        the registrant, incorporated by reference to Exhibit 10(o)
        to the 1995 Form 10-K.
10(dd)  Forms of Agreement dated December 30, 1994, between the
        registrant and certain officers of the registrant,
        concerning a change in control of the registrant,
        incorporated by reference to Exhibit 10(p) to the 1995 Form
        10-K.
10(ee)  Form of Agreement of Indemnification dated August 8, 1995,
        between the registrant and certain officers and directors of
        the registrant, incorporated by reference to Exhibit 10(q)
        to the 1995 Form 10-K.
10(ff)  Supplemental Retirement Benefits Plan, for eligible
        employees of PCS Phosphate Company, Inc., incorporated by
        reference to Exhibit 10(s) to the 1995 Form 10-K.
10(gg)  Second Amended and Restated Membership Agreement dated
        January 1, 1995, among Phosphate Chemicals Export
        Association, Inc. and members of such association, including
        Texasgulf Inc., incorporated by reference to Exhibit 10(t)
        to the 1995 Form 10-K.
10(hh)  International Agency Agreement dated January 1, 1995,
        between Phosphate Chemicals Export Association, Inc. and
        Texasgulf Inc. establishing Texasgulf Inc. as exclusive
        marketing agent for such association's wet phosphatic
        materials, incorporated by reference to Exhibit 10(u) to the
        1995 Form 10-K.
10(ii)  General Partnership Agreement forming Albright & Wilson
        Company, dated July 29, 1988 and amended January 31, 1995,
        between Texasgulf Inc. and Albright & Wilson Americas Inc.,
        incorporated by reference to Exhibit 10(v) to the 1995 Form
        10-K.
10(jj)  Amendment to the Albright & Wilson Company General
        Partnership agreement dated March 23, 2000.
10(kk)  Royalty Agreement dated October 7, 1993, by and between the
        registrant and Rio Algom Limited, incorporated by reference
        to Exhibit 10(x) to the 1995 Form 10-K.
10(ll)  Amending Resolution and revised forms of agreement regarding
        Supplemental Retirement Income Plan of the registrant,
        incorporated by reference to Exhibit 10(x) to the
        registrant's report on Form 10-Q for the quarterly period
        ended June 30, 1996.
10(mm)  Shareholder Rights Agreement as amended and restated on
        March 2, 1998, incorporated by reference to Schedule B to
        the registrant's proxy circular for the annual and special
        meeting of shareholders held on May 7, 1998.
11      Statement re Computation of Per Share Earnings.
13      1999 Annual Report
21      Subsidiaries of the Registrant
23      Consent of Deloitte & Touche LLP.
27      Financial Data Schedule.
</TABLE>