Table S6.

Summary of land area in Iowa by slope class and relevant land-use categories

Slope classAll fields*, haAll agricultural fields, haAll row-crop fields, haAll corn or soybean fields, haAll fields*, %All agricultural fields, %All row-crop fields,%All corn or soybean fields, %
0–4%6,865,6956,396,8215,939,2115,887,16447.143.940.840.4
4–10%3,800,1703,354,2332,754,6372,695,08626.123.018.918.5
>10%2,541,8181,752,1581,087,959985,49717.412.07.56.8
Total13,207,68311,503,2129,781,8079,567,74790.679.067.165.7
  • * The all-fields category includes all agricultural fields and fields not currently in agricultural production (e.g., fallowed or set aside).

  • Agricultural fields include grass hay (Bromus spp., Fescue spp.), alfalfa (Medicago sativa), and pasture fields in addition to row-crop fields.

  • Row crops grown in Iowa are primarily corn and soybean but also include small grain, fruit, and vegetable crops.