John and I looked at Cropscape some yesterday, and we think we’ve found a layer that will be useful-

On this page https://www.nass.usda.gov/Research_and_Science/Cropland/metadata/meta.php  there is a layer for Crop Frequency, which visualizes how many years of the past 10 a crop was planted on a given pixel of the map. It is available for Corn, Soybeans, Wheat and Cotton. We think this will be useful for showing the extent of commodity crops (especially corn) in the Mississippi River watershed. It can be downloaded here. https://www.nass.usda.gov/Research_and_Science/Cropland/Release/index.php  (Jong, I think just we’ll want to clip this down to just show the Mississippi River watershed instead of the whole United States)

Unfortunately, cover crops are not found in this dataset.

Please let me know what you think. It’s a very cool tool, and seems to have decent accuracy according to the metadata. In case you want to explore, here is the link to the web-based tool. https://nassgeodata.gmu.edu/CropScape/

Thanks everyone-

Ted Kratschmer