Water use demand for corn in northeastern South Dakota

An on-farm research study in northeastern South Dakota has been in place since 2012 to monitor in-season water demand by corn. Three hybrids have been planted for the 2012 and 2013 growing seasons, each in large plots 3.7 acres in size to minimize ‘edge effects' and allow for utilization of remote sensing of the crop condition. At least one hybrid variety has been marketed as “drought tolerant”. The crop water use has been calculated using the ASCE-EWRI Standardized Penman-Monteith method utilizing meteorological information collected by a weather station located adjacent to the plots. Landsat imagery will be used to estimate the crop vigor and the crop water consumptive use at three dates during the growing season utilizing the METRIC surface energy balance model. In 2012, a moderate drought affected the region during the growing season, and water demand by the crop exceeded precipitation by nearly 8 inches. In 2013, precipitation exceeded water demand until late July, when a deficit began to accrue quickly, resulting in a late season drought and a similar water deficit by the time of harvest. Yield results will be presented for each hybrid test, as compared to growing season climate and drought characteristics.