South Dakota is home to the largest unbroken stretch of prime waterfowl nesting habitat in the nation — but if farmland continues to gobble up natural areas, the state’s wildlife, landscape, and water quality could all suffer. South Dakota has seen almost 1.1 million acres of rangeland and pasture disappear in the last 20 years, a loss the state’s top wildlife official blames on federal policies and technological innovations that make farming more lucrative than protecting land or using it for grazing. The problem could get worse in 2005, when Roundup-ready wheat becomes available. A product of the Monsanto Company, the genetically modified wheat can withstand exposure to Roundup, an herbicide also sold by Monsanto. The product will allow wheat to be grown in grasslands, which are normally poor areas for wheat farming.