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                                                                   EXHIBIT 10(Z)

                    POTASH CORPORATION OF SASKATCHEWAN INC.
                STOCK OPTION PLAN -- OFFICERS AND KEY EMPLOYEES

1.   PURPOSE OF PLAN

     Potash Corporation of Saskatchewan Inc. (the "Corporation") by resolution
     of its Board of Directors (the "Board") has established this Plan to
     encourage officers and key employees of the Corporation and its
     subsidiaries to promote the growth and profitability of the Corporation by
     providing them with the opportunity through options to acquire Common
     Shares of the Corporation ("Common Shares"). The Corporation's Stock Option
     Incentive Plan, previously in effect, has been bifurcated into this Plan
     and the Corporation's Stock Option Plan -- Directors.

2.   ADMINISTRATION

     This Plan shall be administered by the Board.

3.   GRANT OF OPTIONS

     From time to time the Board may designate individual officers and key
     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 an option to purchase; provided that the
     aggregate number of Common Shares subject to such options may not exceed
     the number provided for in paragraph 4 of this Plan.

4.   SHARES SUBJECT TO OPTION

     The aggregate number of Common Shares issuable after February 3, 1998
     pursuant to options under this Plan may not exceed 6,926,125 shares. The
     number of Common Shares issuable pursuant to options under this Plan shall
     be subject to adjustment under paragraphs 8 and 9.

     The aggregate number of Common Shares in respect of which options have been
     granted to any one person and which remain outstanding shall not at any
     time exceed 5% of the number of issued and outstanding Common Shares (on a
     non-diluted basis) at that time.

     If any 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 options under this Plan.

5.   OPTION PRICE

     The option price 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 share of the Common Shares 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 share of the Common Shares 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.
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6.   TERMS OF OPTION

     The period during which an option is exercisable may not exceed 10 years
     from the date the option is granted, and the option agreement may contain
     provisions limiting the number of Common Shares with respect to which the
     option may be exercised in any one year. Each 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 clause (b) below dies,
          the legal personal representatives of the optionee will be entitled to
          exercise any unexercised options, including such 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 options terminate;

     (b)  subject to the terms of clause (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 then prevailing
          retirement policy of the Corporation or subsidiary, the optionee will
          be entitled to exercise any unexercised options, including such
          options as may vest after the date of retirement, until the expiry
          date of such options or the date on which such options are otherwise
          terminated in accordance with the provisions of this Plan, failing
          which exercise the 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 the preceding clauses (a) or (b), the optionee will be
          entitled to exercise any unexercised 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 options terminate;
          and

     (d)  each option is personal to the optionee and is not assignable, except
          (i) as provided in the preceding clause (a), and (ii) at the election
          of the Board, an 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 the preceding clauses (a), (b), or (c) shall extend
     the period during which an option may be exercised beyond its stipulated
     expiry date or the date on which it is otherwise terminated in accordance
     with the provisions of this Plan.

     If an option is assigned pursuant to the preceding subclause (ii) of clause
     (d), the references in the preceding clauses (a), (b) and (c) to the
     termination of employment or death of an optionee shall not relate to the
     assignee of an 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 option, but the
     assignee of the option or the legal personal representatives of the
     assignee may exercise the option during the applicable specified period.

7.   EXERCISE OF OPTIONS

     Subject to the provisions of this Plan, an 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 shares with respect to
     which the option is being exercised and accompanied by payment in cash or
     certified cheque in full of the purchase price of the shares then being
     purchased.

8.   ADJUSTMENTS

     Appropriate adjustments in the number of shares optioned and in the option
     price per share, both as to options granted or to be granted, may be made
     by the Board in its discretion 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
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     Corporation. If the Corporation sells all or substantially all of its
     assets as an entirety or substantially as an entirety, options under this
     Plan may be exercised, in whole or in part, at any time up to and including
     (but not after) a date 30 days following the date of completion of such
     sales or prior to the close of business on the date the option expires,
     whichever is earlier.

9.   MERGERS

     If 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 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 shares, with appropriate adjustments, so as to give effect to the
     continuance of the 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 options.

10.  CHANGE OF CONTROL

     If a "change of control" of the Corporation occurs, each 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 paragraph
     10, a change of control of the Corporation shall be deemed to have occurred
     if:

     (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.
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11.  AMENDMENT OR DISCONTINUANCE OF THIS PLAN

     The Board may amend or discontinue the Plan at any time but, subject to
     paragraphs 8, 9, and 10, no such amendment may increase the aggregate
     maximum number of shares that may be subject to option under this Plan,
     change the manner of determining the minimum option price, extend the
     option period under any option beyond 10 years or, without the consent of
     the holder of the option, alter or impair any option previously granted to
     an optionee under this Plan. Amendments to the Plan require pre-clearance
     of The Toronto Stock Exchange and the Montreal Exchange.

12.  EVIDENCE OF OPTIONS

     Each option granted under this Plan shall be embodied in a written option
     agreement between the Corporation and the optionee which shall give effect
     to the provisions of this Plan.