Exhibit 4.7**AMENDMENT NO. 6 TO THE AMENDED AND RESTATED CREDIT AGREEMENT**     Amendment No. 6 (this “*Amendment*”), dated as of August 28, 2007, among TerraCapital, Inc., a Delaware corporation (“*Terra Capital*”), Terra Mississippi Holdings Corp.(f/k/a Mississippi Chemical Corporation), a Mississippi corporation (“*TMH*”), and TerraNitrogen (U.K.) Limited, a company incorporated in England and Wales (“*TerraUK*”) (Terra Capital, TMH and Terra UK each a “*Borrower*” and, collectively, the“*Borrowers*”), Terra Industries Inc., a Maryland corporation (“*Terra Industries*”),Terra Capital Holdings, Inc., a Delaware corporation (“*Terra Capital Holdings*”), theLenders party hereto and Citicorp USA, Inc., as administrative agent and collateral agentfor the Lenders and the Issuers (in such capacities, the “*Administrative Agent*”), amends certainprovisions of the Amended and Restated Credit Agreement, dated as of December 21, 2004 (asamended, supplemented or otherwise modified from time to time, including previous amendmentshereto, the “*Credit Agreement*”), amongthe Borrowers, Terra Industries, Terra CapitalHoldings, the financial institutions from time to time party thereto as lenders (the “*Lenders*”),the financial institutions from time to time party thereto as issuing banks (the “*Issuers*”) andCiticorp USA, Inc., as administrative agent and collateral agent for the Lenders and theIssuers (in such capacities, the “*Administrative Agent*”).W I T N E S S E T H:     WHEREAS, the Borrowers, Terra Industries and Terra Capital Holdings have requested, and theRequisite Lenders and the Administrative Agent have agreed to, certain amendments to the CreditAgreement as more specifically set forth below.     NOW, THEREFORE, in consideration of the premises and the mutual covenants and provisionshereinafter contained, the parties hereto hereby agree as follows:     **1. ****Defined Terms**. Capitalized terms used herein and not defined herein but definedin the Credit Agreement are used herein as defined in the Credit Agreement.     **2. ****Amendments**. Upon the occurrence of the Sixth Amendment Effective Date (as definedin Section 4), the Credit Agreement is hereby amended as follows:     (a) The definition of “*Cash Equivalents*” in *Section 1.1*of the Credit Agreement is herebyamended by replacing the word “and” appearing immediately before *clause (g)*with a semi-colon andinserting immediately after the semi-colon at the end of *clause (g)*the following new clause:     and (h) investments in institutional money market funds registered under theInvestment Company Act of 1940, subject to the written consent of the AdministrativeAgent.     (b) *Section 8.**3(k)* of the Credit Agreement is hereby amended by deleting the existing *clause(iv)*in its entirety and inserting the following in lieu thereof:     (iv) by Terra Canada in Terra UK in the form of an Equity Issuance inconnection with Terra Canada’s assumption of, or Terra UK’s repayment of, all ofTerra UK’s liabilities under the Terra UK Fixed Asset Secured Debt;     (c) *Clause (h)*of *Section 8.4*inserted in Amendment No. 5 is hereby renumbered as *clause (i)*.
 

 
     (d) *Section 8.4*of the Credit Agreement is hereby amended by (A) deleting the word “and”appearing at the end of *clause (h),*(B) deleting the “period” appearing at the end of *clause (i)*and inserting “; and” in lieu thereof, and (C) inserting a new *clause (j)*immediately after *clause(i)*to read as follows:     (j) Investments permitted under *Section 8.**3(k)(iv)*.     (e) *Section 8.**5(e)* of the Credit Agreement is hereby amended by:     (i) deleting and replacing *clause (i)*thereof with the following:     (i) the aggregate amount of such Stock Purchases together with theaggregate amount of Common Unit Purchases and the Senior Note Purchases, (A)made during any Repurchase Period does not exceed the Maximum RepurchaseAmount applicable to such period or (B) made during any calendar year doesnot exceed $100,000,000; *provided*, *however*, that for so long as the SeniorUnsecured Note (2007) Indenture remains in full force and effect, theforegoing limitations in clauses (A) and (B) above shall not apply to theextent that such Stock Purchases may at the applicable time be made as a“Restricted Payment” as defined in, and solely in accordance with theprovisions of Sections 4.10(a), 4.10(b)(7) or 4.10(b)(8) of, the SeniorUnsecured Note (2007) Indenture (without giving effect to any amendment ormodification thereof).     and     (ii) deleting and replacing *clause (vi)*thereof with the following:     (vi) Terra Capital shall deliver to the Administrative Agent, togetherwith the quarterly financial information delivered pursuant to Section6.1(b), a certificate executed by an officer of Terra Capital identifyingthe Stock Purchases made during the most recently ended Fiscal Quarter andcertifying that the foregoing conditions were in each case met with respectthereto.     (f) *Section 1.1***(Defined Terms)** of the Credit Agreement is hereby amended by insertingthe following definition in alphabetical order:     “*Amendment No. 5*” means Amendment No. 5, dated as of July 11, 2007, by andbetween the Borrowers, certain subsidiaries of Terra Industries, the AdministrativeAgent and the Lenders signatory thereto.     **3. ****Waiver****.**The Requisite Lenders hereby waive, upon the occurrence of the SixthAmendment Effective Date, any Default or Event of Default that may have occurred prior to suchdate as a result of any breach of the certification requirements of Section 8.5(e)(vi) of theCredit Agreement.     **4. ****Conditions Precedent to the Effectiveness of this Amendment****.**This Amendment shallbecome effective on the date (the “*Sixth Amendment Effective Date*”) when the following conditionsprecedent have been satisfied:
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     (a) Certain Documents. The Administrative Agent shall have received on or before theSixth Amendment Effective Date, all of the following, each of which shall be in form and substancesatisfactory to the Administrative Agent:               (i) this Amendment, executed by the Borrowers, Terra Industries, Terra Capital Holdings, theAdministrative Agent and the Requisite Lenders; and               (ii) such additional documentation as the Administrative Agent or the Lenders may reasonablyrequire.          (b) Representations and Warranties. Each of the representations and warranties madeby the Borrowers or the Guarantors in or pursuant to the Credit Agreement, as amended hereby, andthe other Loan Documents to which any of the Borrowers or the Guarantors is a party or by which theBorrowers or the Guarantors are bound, shall be true and correct in all material respects on and asof the Sixth Amendment Effective Date (other than representations and warranties in any such LoanDocument which expressly speak as of a specific date, which shall have been true and correct in allmaterial respects as of such specific date).          (c) No Event of Default. No Default or Event of Default shall have occurred and becontinuing on the Sixth Amendment Effective Date.          (d) Fees and Expenses Paid. The Borrowers shall have paid to the Administrative Agentin accordance with Section 11.3 of the Credit Agreement, all outstanding costs and expenses of theAdministrative Agent, including the reasonable fees and out-of-pocket expenses of counsel for theAdministrative Agent incurred prior to or otherwise in connection with this Amendment to the extentinvoiced to the Borrowers.     **5. ****Representations and Warranties****.**On and as of the date hereof, and as of the SixthAmendment Effective Date, after giving effect to this Amendment, each Borrower, Terra Industriesand Terra Capital Holdings hereby represents and warrants to the Lenders as follows:          (a) Each of the representations and warranties contained in Article IV of the CreditAgreement, the other Loan Documents or in any certificate, document or financial or other statementfurnished at any time under or in connection therewith are true and correct in all materialrespects on and as of the date as if made on and as of such date, except to the extent that suchrepresentations and warranties specifically relate to a specific date, in which case suchrepresentations and warranties shall be true and correct in all material respects as of suchspecific date; *provided*, *however*, that references therein to the “*Credit Agreement*” shall be deemedto include this Amendment; and          (b) No Default or Event of Default has occurred and is continuing.     **6. ****Continuing Effect; No other Amendments****.**Except as expressly amended hereby orwaiver herein, all of the terms and provisions of the Credit Agreement and the other LoanDocuments are, and shall remain, in full force and effect. The amendments and consents containedherein shall not constitute an amendment or a waiver of any other provision of the CreditAgreement or the other Loan Documents or for any purpose except as expressly set forth herein.     **7. ****Loan Documents****.**This Amendment is deemed to be a “Loan Document” for the purpo**ses**of the Credit Agreement.
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     **8. ****Costs and Expenses****.**The Borrowers, Terra Industries and Terra Capital Holdingsagree to pay on demand all reasonable and documented out-of-pocket costs and expenses of theAdministrative Agent in connection with the preparation, execution and delivery of this Amendmentand other instruments and documents to be delivered pursuant hereto, including the reasonable anddocumented fees and out-of-pocket expenses of counsel for the Administrative Agent with respectthereto.     **9. ****Governing Law; Counterparts; Miscellaneous****.**          (a) This Amendment shall be governed by, and construed and interpreted in accordance with, thelaw of the State of New York.          (b) This Amendment may be executed in any number of counterparts and by the different partieson separate counterparts, each of which counterparts when executed and delivered shall be anoriginal, but all of which shall together constitute one and the same instrument.          (c) Section captions used in this Amendment are for convenience only and shall not affect theconstruction of this Amendment.          (d) From and after the Sixth Amendment Effective Date, all references in the Credit Agreementto the “Agreement” shall be deemed to be references to such Agreement as modified hereby and thisAmendment and the Credit Agreement shall be read together and construed as a single instrument.[signature pages follow]
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     IN WITNESS WHEREOF, the undersigned parties have executed this Amendment No. 6 to the Amendedand Restated Credit Agreement to be effective for all purposes as of the Sixth Amendment EffectiveDate.       Borrowers       Terra Capital, Inc.       By: */s/ Daniel D. Greenwell*         Name: Daniel D. Greenwell