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Exhibit 10(dd)
 2006 Performance Option Plan
 1.
    
    PURPOSE OF PLANPotash Corporation of Saskatchewan Inc. (the Corporation) by resolution of its Board of
Directors (the Board) has established, subject to shareholder approval at the Corporations
2006 Annual and Special Meeting of shareholders, this Potash Corporation of Saskatchewan Inc.
2006 Performance Option Plan (the Plan) to support the Corporations compensation philosophy
of providing selected employees and officers with an opportunity to: promote the growth and
profitability of the Corporation; align their interests with shareholders; and earn compensation
commensurate with corporate performance. The Corporation believes this Plan will directly assist
in supporting the Corporations compensation philosophy by providing participants with the
opportunity through stock options, which will vest, if at all, based on corporate performance
over a three-year period, to acquire Common Shares of the Corporation (Common Shares).2.
    
    DURATION OF THIS PLANThis Plan was adopted by the Board on February 27, 2006 to be effective as of January 1, 2006
(the Effective Date), subject to shareholder approval at the Corporations 2006 Annual and
Special Meeting of shareholders, and shall remain in effect, unless sooner terminated as
provided herein, until one (1) year from the Effective Date, at which time it will terminate.
After this Plan is terminated, no stock options may be granted but stock options previously
granted shall remain outstanding in accordance with their applicable terms and conditions and
this Plans terms and conditions.3.
    
    ADMINISTRATIONThis Plan shall be administered by the Compensation Committee of the Board or any other
committee designated by the Board to administer this Plan (the Committee). The Committee shall
be responsible for administering this Plan, subject to this Section 3 and the other provisions
of this Plan. The Committee may employ attorneys, consultants, accountants, agents, and other
individuals, any of whom may be an employee, and the Committee, the Corporation, and its
officers and directors shall be entitled to rely upon the advice, opinions, or valuations of any
such individuals. All actions taken and all interpretations and determinations made by the
Committee shall be made in the Committees sole discretion and shall be final and binding upon
the participants, the Corporation, and all other interested individuals. To the extent
applicable, the Plan shall be administered with respect to optionees subject to the laws of the
U.S. so as to avoid the application of penalties pursuant to Section 409A of the Internal
Revenue Code.4.
    
    AUTHORITY OF THE COMMITTEEThe Committee shall have full and exclusive discretionary power to interpret the terms and the
intent of this Plan and any Stock Option Award Agreement or other agreement or document
ancillary to or in connection with this Plan, to determine eligibility for stock options and to
adopt such rules, regulations, forms, instruments, and guidelines for administering this Plan as
the Committee may deem necessary or proper. Such authority shall include adopting modifications
and amendments to any Stock Option Award Agreement that are necessary to comply with the laws of
the countries and other jurisdictions in which the Corporation and/or its subsidiaries operate.5.
    
    SHARES SUBJECT TO STOCK OPTIONSThe aggregate number of Common Shares issuable after February 27, 2006 pursuant to stock options
under this Plan may not exceed 1,400,000 Common Shares. The aggregate number of Common Shares in
respect of which stock options have been granted to any one person pursuant to this Plan and
which remain outstanding shall not at any time exceed 300,000. The authorized limits under this
Plan shall be subject to adjustment under Sections 12 and 13.If any stock option granted under this Plan, or any portion thereof, expires or
terminates for any reason without having been exercised in full, the Common Shares with
respect to which such option has not been exercised shall again be available for further stock
options under this Plan; provided, however, that any stock option that is granted under this
Plan that does not vest as a result of a failure to satisfy the Performance Measures, shall
not be again available for grant under this Plan.6.
    
    GRANT OF STOCK OPTIONSFrom time to time the Board may designate individual officers and employees of the Corporation
and its subsidiaries eligible to be granted options to purchase Common Shares and the number of
Common Shares which each such person will be granted a stock option to purchase; provided that
the aggregate number of Common Shares subject to such stock
options may not exceed the number provided for in Section 5 of this Plan. Non-employee directors
and other non-employee contractors and third party vendors are not eligible to participate in
this Plan.




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7.
    
    OPTION PRICEThe option price for any option granted under this Plan to any optionee shall be fixed by the
Board when the option is granted and shall be not less than the fair market value of the Common
Shares at such time which, for optionees resident in the United States and any other optionees
designated by the Board, shall be deemed to be the closing price per Common Share on the New
York Stock Exchange on the last trading day immediately preceding the day the option is granted
and, for all other optionees, shall be deemed to be the closing price per Common Share on the
Toronto Stock Exchange on the last trading day immediately preceding the day the option is
granted; provided that, in either case, if the Common Shares did not trade on such exchange on
such day the option price shall be the closing price per share on such exchange on the last day
on which the Common Shares traded on such exchange prior to the day the option is granted.8.
    
    VESTING OF STOCK OPTIONSSubject to achievement of Performance Measures as certified and approved by the Audit Committee
of the Board, stock options granted under this Plan will vest no later than thirty (30) days
after the audited financial statements for the applicable Performance Period have been approved
by the Board.9.
    
    PERFORMANCE MEASURES FOR VESTING OF STOCK OPTIONS
 (a)
    
    The Performance Measures which will be used to determine the degree to which stock
options will vest over the three-year period beginning the first day of the fiscal year in
which they are granted (the Performance Period) shall be cash flow return on investment
(CFROI) and weighted average cost of debt and equity capital (WACC).
 (i)
    
    CFROI is the ratio of after tax operating cash flow to average gross investment
over the fiscal year, calculated as A divided by B, where (1) A equals operating income
plus nonrecurring or unusual items plus accrued incentive awards plus depreciation and
amortization less cash taxes, and (2) B equals the average of total assets plus
accumulated depreciation plus accumulated amortization less cash and cash equivalents
less non interest bearing current liabilities.(ii)
    
    WACC is the weighted average cost of debt and equity capital, calculated as [A
times the product of B divided by C] plus [D times the product of E divided by C],
where (1) A equals the after-tax market yield cost of debt, (2) B equals the market
value of debt less cash and cash equivalents (3) C equals the market value of debt less
cash and cash equivalents, plus the market value of equity, (4) D equals the cost of
equity, and (5) E equals the market value of equity.
 (b)
    
    In determining the number of stock options that will actually vest based on the degree
to which the Performance Measures have been attained during the applicable Performance
Period, the following chart shall be utilized which shows the three year average excess of
CFROI being greater than WACC and the respective portion of the stock option that will
vest:
 Performance Measure
    
    Vesting Scale3 year average excess of
    
    % of Stock OptionCFROI> WACC
    
    Grant Vesting<0%
    
    0%0.20%
    
    30%1.20%
    
    70%2.20%
    
    90%2.50%
    
    100%
 (c)
    
    In assessing the portion of the stock options that shall vest in accordance with the
above chart, the following shall be done:
 (i)
    
    Each year, the CFROI and WACC will be calculated in accordance with the
definitions herein, based on the audited financial statements and approved by the Audit
Committee.(ii)
    
    In each Performance Period, the average of the three fiscal years shall be
calculated by taking the simple average of the individual years results.




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(iii)
    
    The resulting three-year average will then be applied, using the scale above
to determine the number of stock options, if any, that will vest as of the end of the
Performance Period.(iv)
    
    For results falling between the reference points in the chart above, the level
of vesting shall be mathematically interpolated between the reference points.
 10.
    
    TERMS OF STOCK OPTIONSThe period during which a stock option is exercisable may not exceed 10 years from the date the
stock option is granted, and the Stock Option Award Agreement may contain provisions limiting
the number of Common Shares with respect to which the stock option may be exercised in any one
year. Each stock option agreement shall contain provisions to the effect that:
 (a)
    
    if the employment of an optionee as an officer or employee of the Corporation or a
subsidiary terminates, by reason of his or her death, or if an optionee who is a retiree
pursuant to Section 10(b) dies, the legal personal representatives of the optionee will be
entitled to exercise any unexercised vested options, including such stock options that may
vest after the date of death, during the period ending at the end of the twelfth calendar
month following the calendar month in which the optionee dies, failing which exercise the
stock options terminate;(b)
    
    subject to the terms of Section 10(a) above, if the employment of an optionee as an
officer or employee of the Corporation or a subsidiary terminates, by reason of retirement
in accordance with the then prevailing retirement policy of the Corporation or subsidiary,
the optionee will be entitled to exercise any unexercised vested stock options, including
such stock options that may vest after the date of retirement, during the period ending at
the end of the 36th month following the calendar month in which the optionee retires,
failing which exercise the stock options terminate;(c)
    
    if the employment of an optionee as an officer or employee of the Corporation or a
subsidiary terminates, for any reason other than as provided in Sections 10(a) or (b), the
optionee will be entitled to exercise any unexercised vested stock options, to the extent
exercisable at the date of such event, during the period ending at the end of the calendar
month immediately following the calendar month in which the event occurs, failing which
exercise the stock options terminate;(d)
    
    for greater certainty and for these purposes, an optionees employment with the
Corporation or a subsidiary shall be considered to have terminated effective on the last
day of the optionees actual and active employment with the Corporation or subsidiary
whether such day is selected by agreement with the optionee or unilaterally by the
Corporation or subsidiary and whether with or without advance notice to the optionee. For
the avoidance of doubt, no period of notice that is given or ought to have been given under
applicable law in respect of such termination of employment will be utilized in determining
an optionees entitlement under the Plan. The employment of an optionee with the
Corporation shall be deemed to have terminated for all purposes of the Plan if such person
is employed by or provides services to a person that is a subsidiary of the Corporation and
such person ceases to be a subsidiary of the Corporation, unless the Committee determines
otherwise; and(e)
    
    each stock option is personal to the optionee and is not assignable, except (i) as
provided in Section 10(a), and (ii) at the election of the Board, a stock option may be
assignable to the spouse, children and grandchildren of the original optionee and to a
trust, partnership or limited liability company, the entire beneficial interest of which is
held by one or more of the foregoing.
 Nothing contained in Sections 10(a), (b) or (c) shall extend the
period during which a stock option may be exercised beyond its
stipulated expiration date or the date on which it is otherwise
terminated in accordance with the provisions of this Plan.If a stock option is assigned pursuant to Section 10(e)(ii),
the references in Sections 10(a), (b) and (c) to the termination of
employment or death of an optionee shall not relate to the assignee
of a stock option but shall relate to the original optionee. In the
event of such assignment, legal personal representatives of the
original optionee shall not be entitled to exercise the assigned
stock option, but the assignee of the stock option or the legal
personal representatives of the assignee may exercise the stock
option during the applicable specified period.11.
    
    EXERCISE OF STOCK OPTIONSSubject to the provisions of this Plan, a vested stock option may be exercised from time to time
by delivering to the Corporation at its registered office a written notice of exercise
specifying the number of Common Shares with respect to which the stock option is being exercised
and accompanied by payment in cash or certified cheque in full of the purchase price of the
Common Shares then being purchased.




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12.
    
    ADJUSTMENTSAppropriate adjustments to the authorized limits set forth in Section 5, in the number, class
and/or type of Common Shares optioned and in the option price per share, both as to stock
options granted or to be granted, shall be made by the Board to give effect to adjustments in
the number of Common Shares which result from subdivisions, consolidations or reclassifications
of the Common Shares, the payment of share dividends by the Corporation, the reconstruction,
reorganization or recapitalization of the Corporation or other relevant changes in the capital
of the Corporation.13.
    
    MERGERSIf the Corporation proposes to amalgamate or merge with another body corporate, the Corporation
shall give written notice thereof to optionees in sufficient time to enable them to exercise
outstanding vested stock options, to the extent they are otherwise exercisable by their terms,
prior to the effective date of such amalgamation or merger if they so elect. The Corporation
shall use its best efforts to provide for the reservation and issuance by the amalgamated or
continuing corporation of an appropriate number of Common Shares, with appropriate adjustments,
so as to give effect to the continuance of the stock options to the extent reasonably
practicable. In the event that the Board determines in good faith that such continuance is not
in the circumstances practicable, it may upon 30 days notice to optionees terminate the stock
options.14.
    
    CHANGE OF CONTROLIf a change of control of the Corporation occurs, each then outstanding stock option granted
under this Plan may be exercised, in whole or in part, even if such option is not otherwise
exercisable by its terms. For purposes of this Plan, a change of control of the Corporation
shall be deemed to have occurred if any of the following occur, unless the Board adopts a plan
after the Effective Date of this Plan that has a different definition (in which case such
definition shall be applied), or the Committee decides to modify or amend the following
definition through an amendment of this Plan:
 (a)
    
    within any period of two consecutive years, individuals who at the beginning of such
period constituted the Board and any new directors whose appointment by the Board or
nomination for election by shareholders of the Corporation was approved by a vote of at
least a majority of the directors then still in office who either were directors at the
beginning of the period or whose appointment or nomination for election was previously so
approved, cease for any reason to constitute a majority of the Board;(b)
    
    there occurs an amalgamation, merger, consolidation, wind-up, reorganization or
restructuring of the Corporation with or into any other entity, or a similar event or
series of such events, other than any such event or series of events which results in
securities of the surviving or consolidated corporation representing 50% or more of the
combined voting power of the surviving or consolidated corporations then outstanding
securities entitled to vote in the election of directors of the surviving or consolidated
corporation being beneficially owned, directly or indirectly, by the persons who were the
holders of the Corporations outstanding securities entitled to vote in the election of
directors of the Corporation prior to such event or series of events in substantially the
same proportions as their ownership immediately prior to such event of the Corporations
then outstanding securities entitled to vote in the election of directors of the
Corporation;(c)
    
    50% or more of the fixed assets (based on book value as shown on the most recent
available audited annual or unaudited quarterly consolidated financial statements) of the
Corporation are sold or otherwise disposed of (by liquidation, dissolution, dividend or
otherwise) in one transaction or series of transactions within any twelve month period;(d)
    
    any party, including persons acting jointly or in concert with that party, becomes
(through a take-over bid or otherwise) the beneficial owner, directly or indirectly, of
securities of the Corporation representing 20% or more of the combined voting power of the
Corporations then outstanding securities entitled to vote in the election of directors of
the Corporation, unless in any particular situation the Board determines in advance of such
event that such event shall not constitute a change of control; or(e)
    
    the Board approves and/or recommends that shareholders accept, approve or adopt any
transaction that would constitute a change of control under clause (b), (c) or (d) above
and determines that the change of control resulting from such transaction will be deemed to
have occurred as of a specified date earlier than the date under (b), (c) or (d), as
applicable.




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15.
    
    AMENDMENT OR DISCONTINUANCE OF THIS PLANThe Board may amend or discontinue the Plan at any time, without obtaining the approval of
shareholders of the Corporation unless required by the relevant rules of the Toronto Stock
Exchange, provided that, subject to Sections 12, 13, and 14, no such amendment may increase the
aggregate maximum number of Common Shares that may be subject to stock options under this Plan,
change the manner of determining the minimum option price, extend the option period under any
option beyond 10 years, expand the assignment provisions of the Plan, permit non-employee
directors to participate in the Plan or, without the consent of the holder of the option, alter
or impair any option previously granted to an optionee under this Plan; and, provided further,
for greater certainty, that, without the prior approval of the Corporations shareholders, stock
options issued under this Plan shall not be repriced, replaced, or regranted through
cancellation, or by lowering the option price of a previously granted stock option.
Pre-clearance of the Toronto Stock Exchange of amendments to the Plan will be required to the
extent provided under the relevant rules of the Toronto Stock Exchange.16.
    
    EVIDENCE OF STOCK OPTIONSEach stock option granted under this Plan shall be evidenced by a written stock option agreement
between the Corporation and the optionee which shall give effect to the provisions of this Plan
and include such other terms as the Committee shall determine (Stock Option Award Agreement).17.
    
    WITHHOLDINGTo the extent that the Corporation is required to withhold federal, provincial, state, local or
foreign taxes in connection with any payment made or benefit realized by an optionee or other
person hereunder, and the amounts available to the Corporation for such withholding are
insufficient, it shall be a condition to the receipt of such payment or the realization of such
benefit that the optionee or such other person make arrangements satisfactory to the Corporation
for payment of the balance of such taxes required to be withheld, which arrangements (in the
discretion of the Board) may include relinquishment of a portion of such benefit. Participants
shall also make such arrangements in connection with the disposition of Common Shares acquired
upon the exercise of option rights with respect to this Plan.




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(Potash Logo)
    
    Potash Corporation of Saskatchewan Inc.
 This certificate evidences and confirms the grant to  (the Optionee) of options to purchase the number of Common Shares of the Corporation specified
under Paragraph (1) on the terms and subject to the conditions of the Potash Corporation of Saskatchewan Inc. 2006 Performance Option Plan (the 2006 Plan) and the terms and
conditions set forth below. In the event of any inconsistency between the terms of the 2006 Plan and those set forth below, the terms of the 2006 Plan shall control. Capitalized
terms used below that are not defined in this certificate shall have the meanings specified in the 2006 Plan.
 1.
    
    Number of Shares:The Optionee is hereby granted options under the 2006 Plan to Purchase  Common Shares.2.
    
    Option Exercise Price:The exercise price for each Common Share is $.3.
    
    Time and Conditions to Vesting:The options will become vested following the end of the Performance Period January 1, 2006 through December 31, 2008 if, and to the extent,
the applicable Performance Measures for the Performance Period are achieved. Subject to applicable conditions under the 2006 Plan with respect to continued employment during the
Performance Period and achievement of the minimum Performance Measures, the date for vesting will be determined but will not be later than 30 days after the audited financial
statements of the Corporation for the 2008 fiscal year of the Corporation have been approved by the Board. Upon vesting, the Optionee will have the right to purchase a number of
Common Shares covered by the option equal to the percentage determined in accordance with the performance matrix and vesting scale provided under the 2006 Plan.4.
    
    Once vested, the options will continue to be exercisable until the expiry date for the options of May 4, 2016.5.
    
    Notwithstanding the provisions of paragraph 4 above, this option will terminate as provided in paragraph 10 of the 2006 Plan in the event that the actual and active employment
of the Optionee ceases. The option is personal to the Optionee and is not assignable, except in accordance with the conditions attached hereto as Appendix I.6.
    
    Notice of exercise of the option is to be given in accordance with paragraph 11 of the 2006 Plan.7.
    
    Adjustments to the option may be made as provided in paragraph 12 of the 2006 Plan, the provisions of paragraph 13 of the 2006 Plan shall apply in the event of a proposed
amalgamation or merger of the Corporation, and the provisions of paragraph 14 of the 2006 Plan will apply in the event of a change of control of the Corporation as defined in
that paragraph.8.
    
    This grant of option is subject to receipt of any necessary regulatory approvals and shall be governed by the laws of Saskatchewan.
 Potash Corporation of Saskatchewan Inc.Date:
    By:President and Chief Executive Officer