Wikipedia
Swampbuster is a provision of the Food Security Act of 1985 (P.L. 99-198) that discourages the conversion of wetlands to cropland use.
Producers converting a wetland area to cropland lose eligibility for several federal farm program benefits. Benefits are lost from when water levels are lowered to facilitate agricultural production until they have been restored. Several types of wetlands and wetlands in specified situations are exempt. Exceptions include conversions that began before December 23, 1985, conversions of wetlands that had been created artificially, crop production on wetlands that became dry through drought, and conversions that USDA has determined have minimal effect on wetland values. Swampbuster provisions were amended in the 1996 farm bill (P.L. 104-127) to provide greater flexibility for producers and landowners. The 2002 farm bill (P.L. 107-171, Sec. 2002) made only a single change prohibiting third party providers from making swampbuster determinations.