The Secretary of Agriculture may enter into multiyear set-aside contracts for a period not to extend beyond the 1990 crops. Such contracts may be entered into only as a part of the programs in effect for the 1986 through 1990 crops of wheat, feed grains, upland cotton, and rice, and only producers participating in one or more of such programs shall be eligible to contract with the Secretary under this section. Producers agreeing to a multiyear set-aside agreement shall be required to devote the set-aside acreage to vegetative cover capable of maintaining itself through such period to provide soil protection, water quality enhancement, wildlife production, and natural beauty. Grazing of livestock under this section shall be prohibited, except in areas of a major disaster, as determined by the President, if the Secretary finds there is a need for such grazing as a result of such disaster. Producers entering into agreements under this section shall also agree to comply with all applicable State and local laws and regulations governing noxious weed control.