These unit process models represent crop production in US states in multiple years. The main data source used for the development of the field crop data described here is the annual USDA Agricultural Resource Management Survey (ARMS). ARMS data are from an annual national survey of field-level farm practices sponsored jointly by USDA Economic Research Service (ERS) and the USDA National Agricultural Statistics Service (NASS).

Within ARMS, data representing Crop Production Practices provides annual data summaries for field crops at the state level beginning in 1996, with only select crops surveyed each year: corn (1996, 1997, 1998, 1999, 2000, 2001, 2005); cotton (1996, 1997, 1998, 1999, 2000, 2003, 2007); oats (2005); peanuts (1999, 2004); rice (2006); soybeans (1996, 1997, 1998, 1999, 2000, 2002, 2006); and spring, durum, and winter wheat (1996, 1997, 1998, 2000, 2004, 2009). There are 466 crop-state-year combinations (e.g., the production of soybeans in Iowa in 2006) included. Single year datasets are combined into datasets that represent multiple years of production of a single kg of crop as the weighted production fraction for which single year unit process data have been prepared. Datasets combine 3 or more years of data. There are 70 multi-year datasets representing all field crops except oats, peanuts, and rice.

These datasets were released in ecospold version 1 in June 2012.

Models represent states that produced field crops in the ARMS survey years included.