A Geospatial Comparison of Corn Planting Date Risk Assessment Models for Mississippi.

The shift in cropping system dominance from upland cotton (Gossypium hirsutum L.) to corn (Zea mays L.) in Mississippi has caused variably-scaled disruptions in the connectivity of science and the practices of crop care professionals. “Evidence-based agriculture” models help practitioners keep track of a burgeoning knowledge base in a systematic way, however, dramatic shifts in crop sequences, planting intensities, and weather patterns have produced inter-related complications challenging producers and extension specialists. In sharp contrast to cotton, long-term corn trials on experimental stations have not occurred; therefore, optimal planting intervals as well as yield penalties for continuous production are important knowledge gaps to be filled-in. Geospatial integration of a 5-year corn production footprint (derived from 2009-2013 Cropland Data Layers) with a series of updated temperature-based planting date probability maps enables farmers and other crop professionals to adapt management strategies and minimize risk. Corn production has recently expanded to occupy 56% of Mississippi’s harvested land (based on 2012 Census of Agriculture county-level harvest records). Over half of the counties in the Delta have invested between 60-85% of their arable land in corn across the 5-year study interval. Comparison of risk probability maps generated from weather station versus PRISM-derived-data maps has revealed 2-3 week delays in corn planting dates for two areas in the southern half of Mississippi. Development of an interactive, user-friendly, web-based version of these geospatial agronomic models is underway to further resolve the spatial patterns of extreme years where planting dates were delayed by the persistence of unusually cold weather when compared to the 30-year normal dataset.