Research conducted by Rai A. Schwalbert and Ignacio A. Ciampitti, Kansas State University, as a part of the Pioneer Crop Management Research Awards (CMRA) Program. This program provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America. The awards extend for up to four years and address crop management information needs of Pioneer agronomists, sales professionals, and customers.
* Data Sources:
- Cropland data layer is an annual raster-format land-use maps created by the USDA NASS, based on the Landsat 5 TM, Landsat 7 Enhanced Thematic Mapper (ETM+), the Indian Remote Sensing RESOURCESAT-1 (IRS-P6), Advanced Wide Field Sensors (AwiFS), Landsat TM/ETM+, and AWiFS imagery (the last two since 2010). Since 2008 the raster layers are released on a 30m resolution and cover the continental U.S.
- Historical state- and county-level corn yield information is available for downloading from the Internet in tabular form at the USDA/NASS Quick Stats website. This database is released as a point information in a county level (each point is a county/year yield record) without geographical information such as latitude and longitude.
- Enhanced vegetation index images were obtained from the MODIS /006/MOD13Q1 collection which provides images with 250-meter resolution (each MOD13Q1 pixel contains the best possible observation during a 16-day period). All the images from this collection were gathered between March 1 and November 10, and between May 1 and November 10, from 2008 to 2017, for corn and soybean respectively, in order to cover the entire growing season for these two crops.
- Yearly average temperature and growing degree units (GDU) were derived from the PRISM Daily Spatial Climate Dataset AN81d, this raster layer contains daily and monthly 4 km gridded climate datasets for the U.S., produced by the PRISM Climate Group at Oregon State University.
- Vapor pressure deficit was assessed from the Gridded Surface Meteorological dataset that provides a ~4 km daily surface weather raster layers for the contiguous U.S. This dataset blends the high resolution spatial data from PRISM with the high temporal resolution data from the National Land Data Assimilation System (NLDAS).
- Soil information (clay, available water content, organic matter content, and pH) was gathered from POLARIS, a map of soil series probabilities that has been produced for the contiguous U.S. at a 30-m spatial resolution and using machine learning algorithms to remap the Soil Survey Geographic (SSURGO) database.