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                                                                   EXHIBIT 10.11



                        MISSISSIPPI CHEMICAL CORPORATION

                           SUPPLEMENTAL BENEFIT PLAN


                   AS AMENDED AND RESTATED AS OF JULY 1, 1996
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                               TABLE OF CONTENTS

<TABLE>
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SECTION                                                        PAGE
<C>    <S>                                                     <C>
 
1. Introduction..............................................    1
   1.1  Plan.................................................    1
   1.2  Effective Date.......................................    1
   1.3  Purpose..............................................    1

2. Participation and Supplemental Benefits...................    2
   2.1  Eligibility..........................................    2
   2.2  Supplemental Pension Benefits........................    2
   2.3  Supplemental Thrift Benefits.........................    2
   2.4  Payment of Supplemental Pension Benefits.............    3
   2.5  Payment Modification.................................    3
   2.6  Payment of Supplemental Thrift Benefits..............    4
   2.7  Benefits Provided by Employer........................    4

3. Other Employment..........................................    5

4. General...................................................    6
   4.1  Administrator........................................    6
   4.2  Interests Not Transferable...........................    6
   4.3  Facility of Payment..................................    6
   4.4  Gender and Number....................................    6
   4.5  Controlling Law......................................    6
   4.6  Successors...........................................    6
   4.7  Not a Contact........................................    6

5. Amendment and Termination.................................    7

6. Execution of Plan.........................................    8
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                                   SECTION 1

                                  INTRODUCTION
                                        
     1.1  PLAN.  This plan has been established by Mississippi Chemical
Corporation (the "Employer") for the benefit of eligible employees of the
Employer, and shall be known as the Mississippi Chemical Corporation
Supplemental Benefit Plan (the "Plan").  Subsidiaries and affiliates of the
Employer may not, however, adopt the Plan for the benefit of any of their
employees.

     1.2  EFFECTIVE DATE.  The "Effective Date" of the Plan is July 1, 1984.
The Effective Date of this amendment and restatement of the Plan is July 1,
1996.

     1.3  PURPOSE.  The Plan has been established to supplement retirement
benefits provided by the Employer's qualified defined benefit pension plan,
entitled the Mississippi Chemical Corporation Retirement Plan ("Pension Plan").
To the extent that benefits under such plan are limited by Sections 415 and
401(a)(17) of the Internal Revenue Code of 1986, as amended ("Code"), and the
regulations thereunder (the "Pension Limiting Provisions"), supplemental
benefits are provided under terms and conditions of this Plan.  The plan is also
intended to supplement benefits provided by the Employer's qualified 401(k)
savings plan, entitled the Mississippi Chemical Corporation Thrift Plan Plus
("Thrift Plan").  To the extent that Employer matching contributions under such
plan are limited by Sections 415, 401(a)(17) and 402(g) of the Code, and the
regulations thereunder (the "Thrift Limiting Provisions"), supplemental benefits
are provided under the terms and conditions of this Plan.  The Plan is intended
to be unfunded for purposes of the Code and the Employee Retirement Income
Security Act of 1974, as amended ("ERISA").  For purposes of calculating
benefits under this Plan, the Pension Limiting Provisions and the Thrift
Limiting Provisions shall be deemed to be not less than the dollar and/or
percentage limits in effect as of January 1, 1996.

                                       1
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                                   SECTION 2

                    PARTICIPATION AND SUPPLEMENTAL BENEFITS
                                        
     2.1  ELIGIBILITY.  Each employee of the Employer who is covered by the
Pension Plan or by the Thrift Plan, whose benefits thereunder are or were
limited by the Pension Limiting Provisions or the Thrift Limiting Provisions,
and who is specifically named and nominated in writing by the Administrator for
participation hereunder, will be a Participant under this Plan and, upon
retirement on or after the Effective Date, will be eligible for benefits in
accordance with subsections 2.2 and 2.3 hereof.  Eligibility shall be limited to
a select group of management or highly compensated employees.

     2.2  SUPPLEMENTAL PENSION BENEFITS.  Upon a Participant's termination of
employment, retirement or death on or after the Effective Date, any benefits
which otherwise would have been provided to him or his beneficiary under the
Pension Plan, but which have not been provided to him or his beneficiary because
of the Pension Limiting Provisions shall be calculated and, if appropriate,
shall be valued by an actuary selected by the Employer.  Such benefits
("Supplemental Pension Benefits") shall be the full amount of retirement benefit
produced for the Participant by the Pension Plan's formula without regard to the
Pension Limiting Provisions, less the maximum amount of retirement benefits that
can be provided under the Pension Plan in accordance with the Pension Limiting
Provisions.

     2.3  SUPPLEMENTAL THRIFT BENEFITS.  Upon a Participant's termination of
employment, retirement or death on or after the Effective Date, the accumulated
value of any Employer matching contributions which otherwise would have been
credited to him under the Thrift Plan, but which were not credited to him
because of the operation of the Thrift Limiting Provisions, shall be calculated
as hereinafter provided:

     (a)  Employer matching contributions to be credited for a particular year
          under this Plan shall be equal to the excess of (i) the Employer
          matching contributions that would have been credited under the Thrift
          Plan for the year without regard to the Thrift Limiting Provisions
          over (ii) the actual Employer matching contributions that were
          credited under the Thrift Plan for the year.

     (b)  If a Participant has made salary deferred contributions in the maximum
          amount allowed by Section 402(g) of the Internal Revenue Code and the
          regulations thereunder, it shall be assumed that the Participant would
          have made salary deferral contributions at a level that would have
          produced the maximum Employer matching contributions permitted
          pursuant to the matching formula in the Thrift Plan.

     (c)  The accumulated value of such Employer matching contributions shall be
          determined using an interest rate of eight percent (8%) per annum.

                                       2
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Such accumulated value shall be the Participant's "Supplemental Thrift 
Benefits."

     2.4  PAYMENT OF SUPPLEMENTAL PENSION BENEFITS.  Supplemental Pension
Benefits, subject to the further provisions of the Plan, shall be payable to or
on account of the Participant as follows:

     (a)  on a monthly basis beginning at the same time and under the same terms
          and conditions as would have applied if such benefits were payable on
          a monthly basis from the Pension Plan.

     (b)  on a monthly basis to the Participant's surviving spouse or other
          beneficiary in the event of the Participant's death (before or after
          retirement) beginning at the same time and under the same terms and
          conditions as would have applied if such benefits were payable on a
          monthly basis from the Pension Plan.  Benefits to the surviving spouse
          or other beneficiary shall be based upon the difference between the
          full amount of retirement benefit produced for the Participant by the
          Pension Plan's formula, multiplied by the percentage of such benefit
          payable to the surviving spouse or other beneficiary under the Pension
          Plan, less the amount of benefits being provided to the surviving
          spouse or other beneficiary under the Pension Plan after application
          of the Pension Limiting Provisions.  In no event will any payments be
          made hereunder to or on account of a surviving spouse or other
          beneficiary after the month in which the surviving spouse's death
          occurs.

     All elections made, beneficiaries designated and payment options selected
under the Pension Plan by the Participant, his spouse or his beneficiary shall
be deemed to have been so made, designated or selected for purposes of this
Section 2.4.  No later than the last day of the calendar year immediately prior
to the year payments are to begin hereunder, the Participant shall irrevocably
elect the form of payment of benefits hereunder from among the payment options
available under the Pension Plan.  Such election shall be made in writing and
delivered to the Administrator.  Such election shall not affect the
Participant's right to select his payment option under the Pension Plan within
the time periods established by the Pension Plan and applicable law.  In the
event the Participant fails to make such an irrevocable election, the
Administrator, in its sole discretion, shall determine the form of payment
hereunder.

     2.5  PAYMENT MODIFICATIONS.  Regardless of any other provisions of this
Plan, the period during which any monthly installments hereunder are to be paid
to a Participant or to his surviving spouse or other beneficiary may, at any
time after such person(s) is entitled to payments hereunder, be modified by
mutual agreement between the Administrator and the person(s) to whom such
monthly installments are to be paid.  Notwithstanding anything to the contrary
in the Plan, the Administrator, in its sole discretion, may cause a lump-sum
payment to be made to a Participant in full satisfaction of all amounts payable
hereunder, if the present value 

                                       3
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of all amounts payable hereunder does not exceed $50,000. The amount of such
lump-sum payment and such present value shall be determined in accordance with
the procedures and assumptions specified in Section 5 below.

     2.6  PAYMENT OF SUPPLEMENTAL THRIFT BENEFITS.  Supplemental Thrift
Benefits, subject to the further provisions of this Plan and to the payout
provisions of the Thrift Plan, shall be payable to or on account of the
Participant at the time and in the form as elected by the Participant, or if
applicable the Participant's beneficiary.  All beneficiaries designated under
the Thrift Plan by the Participant shall be deemed to have been designated for
purposes of this Section 2.6.  No later than the last day of the calendar year
immediately prior to the year payments are to begin hereunder, the Participant
shall irrevocably elect the form of payment of benefits hereunder from among the
payment options available under the Thrift Plan.  Such election shall be made in
writing and delivered to the Administrator.  Such election shall not affect the
Participant's right to select his payment option under the Thrift Plan within
the time periods established by the Thrift Plan and applicable law.  In the
event the Participant fails to make such an irrevocable election, the
Administrator, in its sole discretion, shall determine the form of payment
hereunder.

     2.7  BENEFITS PROVIDED BY EMPLOYER.  Benefits payable under this Plan to a
Participant or his spouse or other beneficiary shall be the obligation of the
Employer.  The Employer may, but shall not be required to, sequester any assets
to be applied for the payment of benefits under this Plan. In the event the
Employer elects to establish a grantor trust for the payment of benefits
hereunder, the Employer shall be relieved of liability to the extent of any
payments actually made to Participants by such trust.  Participants shall have
the status of unsecured creditors of the Employer with respect to their benefits
hereunder in all events.

                                       4
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                                   SECTION 3

                               OTHER EMPLOYMENT

     A Participant or his spouse or other beneficiary receiving Supplemental
Pension Benefits or Supplemental Thrift Benefits will continue to be entitled
thereto regardless of other employment or self-employment.

                                       5
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                                   SECTION 4

                                    GENERAL

     4.1  ADMINISTRATOR.  This Plan will be administered by the Employer or by
one or more officers of the Employer who are designated as "Administrator" by
the Board of Directors of the Employer.

     4.2  INTERESTS NOT TRANSFERABLE; TAXES.  Except as to any withholding of
tax under the laws of the United States or any State and except with respect to
a "qualified domestic relations order" as defined in ERISA, the interest of any
Participant or his spouse, minor children of beneficiary under the Plan is not
subject to the claims of creditors and may not be voluntarily or involuntarily
sold, transferred, assigned, alienated or encumbered.  The Administrator shall
have the discretion and sole authority to determine the amount and timing of any
withholding or employment taxes with respect to amounts accrued or paid under
the Plan.  The Employer shall reimburse the Participant for, or pay, any tax
imposed on the Participant under the Federal Insurance Contributions Act with
respect to the Participant's interest in this Plan; however, the Participant
shall be responsible for any taxes resulting from the Employer's payment of such
tax.

     4.3  FACILITY OF PAYMENT.  Any amounts payable hereunder to any person
under legal disability or who, in the judgment of the Administrator, is unable
to properly manage his financial affairs may be paid to the legal representative
of such person or may be applied for the benefit of such person in any manner
which the Administrator may select.

     4.4  GENDER AND NUMBER.  Where the context admits, words in the masculine
gender shall include the feminine gender, the plural shall include the singular
and the singular shall include the plural.

     4.5  CONTROLLING LAW.  To the extent not superseded by the laws of the
United States, the laws of Mississippi shall be controlling in all matters
relating to the Plan.

     4.6  SUCCESSORS.  This Plan is binding on the Employer and will be binding
on and inure to the benefit of any successor of the Employer, whether by way of
purchase, merger, consolidation or otherwise.

     4.7  NOT A CONTRACT.  This Plan does not constitute a contract of
employment and shall not be construed to give any Participant the right to be
retained in the Employer's service.

                                       6
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                                   SECTION 5

                           AMENDMENT AND TERMINATION
                                        
     While the Employer expects to continue the Plan indefinitely, the Board of
Directors of the Employer must necessarily reserve and hereby reserves the right
to amend the Plan at any time, provided that in no event shall any Participant's
Supplemental Pension Benefits or Supplemental Thrift Benefits accrued to the
date of such amendment or termination be modified or reduced by such action,
without the specific written agreement of the Participant to such modification
or reduction.  Notwithstanding the foregoing, in the event the Board elects to
terminate the Plan, the Employer reserves the right to settle all liabilities
under the Plan by paying each Participant a lump-sum payment in full
satisfaction of his benefits hereunder.  Such lump sum shall equal (1) the
present value of the Participant's Supplemental Pension Benefits, determined by
an actuary selected by the Employer, plus (2) the accumulated value of his
Supplemental Thrift Benefits with interest credited through the date of
termination pursuant to Section 2.3 above.  The present value of the
Participant's Supplemental Pension Benefits shall be determined in accordance
with the assumptions designated in Section 1.34 of the Pension Plan, entitled
"Present Value of Accrued Benefit."

                                       7
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                                   SECTION 6

                               EXECUTION OF PLAN
                                        
     To record the amendment and restatement of the Plan, the undersigned, being
duly authorized to act on behalf of the Board of Directors of Mississippi
Chemical Corporation, have executed this document at Yazoo City, Mississippi.

Dated:  June 26, 1996           MISSISSIPPI CHEMICAL CORPORATION


                                By: Plan Administrator

                                    /s/ Ethel Truly
                                    -------------------------------------


                                    /s/ Robert E. Jones
                                    -------------------------------------

                                       8