Exhibit 4.1

THIRD SUPPLEMENTAL INDENTURE

          This Third Supplemental Indenture (the “ Third Supplemental Indenture ”) is made and entered into this 16th day of October, 2009 by and among Terra Capital, Inc., a Delaware corporation (the “ Company ”), Terra Industries Inc., a Maryland corporation, as parent guarantor (the “ Parent ”), each of the subsidiaries of the Company listed in Appendix I attached hereto (each, together with the Parent, the “ Guarantors ”) and U.S. Bank National Association, as trustee under the Indenture referred to below (the “ Trustee ”).

WITNESSETH

          WHEREAS, the Company, the Guarantors and the Trustee are parties to an Indenture (as such may be amended from time to time, the “ Indenture ”), dated as of February 2, 2007, as supplemented by the First Supplemental Indenture dated as of January 9, 2008, and the Second Supplemental Indenture dated as of April 27, 2009, relating to the Company’s 7% Senior Notes due 2017 (the “ Notes ”);

          WHEREAS, pursuant to its offer to purchase and consent solicitation statement dated September 24, 2009 (the “ Offer to Purchase ”), the Company commenced a tender offer for any and all of the outstanding Notes (the “ Tender Offer ”) and solicited the consents of the holders of the Notes to the Proposed Amendments (the “ Consent Solicitation ”);

          WHEREAS, the approval of the holders of a majority of the aggregate principal amount of the Notes outstanding (not including any Notes owned by the Company or by any person directly or indirectly controlling or controlled by or under direct or indirect common control with the Parent) is sufficient to amend the terms of the Indenture as set forth herein;

          WHEREAS, having received the approval of the holders of at least a majority of the aggregate principal amount of the Notes outstanding (not including any Notes owned by the Company or by any person directly or indirectly controlling or controlled by or under direct or indirect common control with the Parent) pursuant to Section 9.2 of the Indenture, the Company and the Trustee desire to amend the Indenture, as provided hereinafter; and

          WHEREAS, all things necessary to make this Third Supplemental Indenture the legal, valid and binding obligation of the Company, the Parent and the Guarantors, upon its execution, have been done;

          NOW, THEREFORE, for good and valuable consideration, the receipt of which is acknowledged, the parties agree as follows for the benefit of each other and for the equal and ratable benefit of the holders of the Notes:

          1. Capitalized Terms . Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

          2. Deletion of Certain Provisions . Each of the following sections of the Indenture is hereby deleted in its entirety and replaced with “Intentionally Omitted” and all references in the Indenture to such sections shall also be deleted in their entirety: