Decision-Support Maps for Corn Planting Date and Crop Maturity in Mississippi.

Mississippi’s shift in cropping system dominance from upland cotton (Gossypium hirsutum L.) to corn (Zea mays L.) has caused variably-scaled challenges (at the field-, farmscape-, and regional-scales) for producers and other crop care professionals. Rather dramatic shifts in crop sequences, commodity prices, planting intensities, and weather patterns have produced inter-related complications associated with the initiation of planting. Ancillary knowledge gaps include: risk assessment determinations, maturity dates based on growing degree units (GDUs), and gauging potential yield penalties for continuous production. Geospatial integration of a 4-year corn production footprint (derived from 2013-2016 Cropland Data Layers) with a series of updated temperature-based planting date probability maps enables farmers and other crop professionals to adapt management strategies, minimize risk, and help improve farm-gate earnings. The 4-year corn production footprint occupies over 50% of Mississippi’s harvested land base. Actually, since 2007, over half of the counties in the Delta have invested between 60-85% of their arable land in corn. Comparison of risk probability maps generated from interpolated weather station point data (N=330) with Parameter-elevation Relationships on Independent Slopes Model (or PRISM-derived data) maps has revealed 2-3 week delays in corn planting dates for two areas in the southern half of Mississippi. Additional spatial analysis, based on PRISM data models (at a resolution of 16 km²), has indicated close to 20% of the statewide acreages could advance planting dates 1-3 weeks at a very low risk of 10%. Decision-support models that integrate time to crop maturity using growing degree units (GDUs) with optimal planting date intervals are the next logical steps to help producers maintain a competitive edge in corn commodity markets.