Researchers at the Geographic Information Science Center for Excellence at South Dakota State University have documented disturbingly high rates of conversion of grasslands to croplands in the western portion of the country's Corn Belt, according to the Wildlife Management Institute.

The investigators analyzed land cover data from the Agricultural Statistics Service Cropland Data Layer to evaluate the magnitude of grassland loss attributed to conversion to crop production in North and South Dakota, Minnesota, Nebraska and Iowa during the period 2006 though 2011. They found the rate of grassland conversion to crops during this recent period was similar to the peak rates documented during the 1920's and 30's when tractors and other mechanized equipment became available for widespread use. The image above shows the relative change rate from grassland in 2006 to corn or soybeans in 2011. The authors of the study believe that the recent doubling in crop commodity prices has created incentive that drives the current high level of grassland conversion.

Specifically, the investigators estimated that 1.3 million acres of grasslands were converted to crops in the five states during the study period. They believe that many of these lands were maintained in grass cover over the years prior to 2006 because they are susceptible to erosion and vulnerable to drought. In addition, in some parts of the study area, grassland conversion seemed to be concentrated near wetlands with obvious dire consequences for nesting waterfowl.

The analysis was conducted by Christopher Wright and Michael Wimberly and was published by the Proceedings of the National Academy of Sciences in early March. (pmr)