Statistical data on estimated seeded and harvested acres, yield, production and farm value by year.

the dataset includes: 1. EPIC_outputs are EPIC yearly output files from Rainfed/Irrigated corn grain simulations using 2006/2011 fertilizer management scenario for the simulation periods of 2002 to 2009 and 2010 to 2017 (e.g. CornGrainIrrig-2006FMS_yrs2002-09.csv: yearly output from 2002 to 2009 for Irrigated Corn grain using 2006 fertilizer management scenario; CornGrainRainfed-2011FMS_yrs2010-2017.csv: yearly output from 2010 to 2017 for Rainfed Corn grain using 2011 fertilizer management scenario); 2. \EPIC_outputsAggregated are saved average annual EPIC output aggregated over entire CONUS or GRIDCELL used for GIS maps including Figures 4, 5 and 9 (e.g. CONUS_2006FMS_AvgOf2003-2009.csv: average annual EPIC output using 2006 fertilizer management scenario for period from 2003 to 2009 and aggregated over CONUS CONUS_GRIDCELL_2006FMS_AvgOf2003-2009.csv: average annual EPIC output using 2006 fertilizer management scenario for period from 2003 to 2009 and aggregated over each CONUS GRIDCELL); 3.\SummaryData_FromEPIC_for_Tables_Figs are saved summarized data for all the tables and Figs in Excel sheets. This dataset is associated with the following publication: Wang, X., Y. Yuan, V. Benson, and L. Ran. An Integrated Multi-Media Modeling System for Regional- to National-Scale Nitrogen and Crop Productivity Assessments. Agriculture. MDPI, Basel, SWITZERLAND, 15(10): 1017, (2025).

Difference from Normal Temperature values are computed by subtracting the normal monthly average temperature from the average monthly temperature of the month. The average monthly temperature is computed by obtaining the mean value of average daily temperatures for a month. If the month was colder than normal the value computed will be negative and if it was warmer the value will be positive. Long-term average is 1991-2020. The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

This data set contains a single data file (.csv format) that provides gridded values of net primary productivity (NPP) for cropland in eight counties in the central United States for the year 1992 and estimates of interannual cropland NPP in Iowa for years from 1982 through 1996. The data file also includes climate, soil texture, and land cover data for each 0.5 degree grid cell. The magnitude and interannual variation in NPP was estimated using crop area and yield data from the U.S. Department of Agriculture, National Agricultural Statistics Service (NASS). The major harvested commodities were corn, soybean, sorghum, sunflower, oats, barley, wheat, and hay. Total NPP estimates include both above- and below-ground components. County-level NPP in 1992 ranged from 195 to 760 gC/m2/year. The area of highest NPP, ranging from 650 to 760 gC/m2/year, was found in a band extending across Iowa, through northern Illinois, Indiana, and southwestern Ohio. Areas of moderate NPP, from 550 to 650 gC/m2/year, occurred mostly in Michigan and Wisconsin, while large areas of low NPP, from 200 to 550 gC/m2/year, occurred in North Dakota, southern Illinois, and Minnesota. The area of highest production was also the area with the largest proportion of land sown with corn and soybean. NPP for counties in Iowa varied among years (1982-1996) by a factor of 2, with the lowest NPP in 1983 (which had an unusually wet spring), in 1988 (which was a drought year), and in 1993 (which experienced floods). Revision Notes: The documentation for this data set has been modified, and the data files have been reformatted. The data files have been checked for accuracy and the contents are identical to those originally published in 2001.