Guaranteeing Robust Agricultural Independence and Nutrition for America Act or the GRAIN for America Act This bill establishes a one-year moratorium on the enrollment of land in the Conservation Reserve Program, with a specified exception for land that is already subject to a contract under the program. It also prohibits the Department of Agriculture from enrolling prime farmland in the program. Additionally, the bill allows a participant who has entered into a contract under the program to terminate the contract at any time during the one-year period preceding the date on which the contact would expire.