Soil Water Availability in Response to Long-Term Agronomic Research.

Soil water is often the most limiting factor for plant growth and yield, and is an excellent indicator of soil quality. This study reports how soil and crop management influences soil plant available water (PAW) by using results from surface Mexico series (Epiaqualf) samples collected in 2014, 125 years after treatment establishment.  Samples were used to determine the soil water characteristic (SWC), soil organic matter, bulk density (BD), and texture from six long-term historical plots of Sanborn Field consisting of continuous corn, wheat, and timothy, with and without application of farmyard manure and continuously since 1888. Organic matter, BD, and texture data from historical samples from 1915, 1938, 1962, and 1988 will be used as input to a pedotransfer function to estimate the SWC for the historical samples. This information will show the influence of soil and crop management on PAW, and will allow estimation of soil physical quality using Dexter’s S-Index. Data from soil and crop management influences on PAW, National Weather Service data from 28 long-term Missouri locations will be input into a Thornthwaite-Mather climatic water budget model to estimate Shaw’s daily moisture stress index from daily evapotranspiration annually.  These data will highlight how soil and crop management influences levels of PAW across Missouri that can impact moisture stress in corn.