Consideration of dryland corn seeding rate after drought
At Mead in southeast Nebraska, response of dryland corn yield to plant population (Figure 1, lower graph) is strongly positive even when soil moisture at planting is as low as 50% F.C. (i.e., 2.2 inches/foot) for a year with average rainfall during the growing season (i.e., 14.8 inches). And the response is even steeper if soil moisture at planting further improves. In this area, typical growing season rainfall can significantly compensate for low soil water storage at start of the growing season, and as a result, the impact of a drought year to the next season is less than in lower-rainfall areas, such as west central Nebraska.
Dryland corn growers in areas with conditions similar to west central Nebraska should consider taking into account the amount of stored soil moisture at planting when determining seeding rates. This may well be the situation in 2013 if the current low soil water storage exists at planting time. The amount of precipitation during the coming winter and spring will be important for recharging soil moisture and thus in making decisions about 2013 seeding rates in dryland fields of west central Nebraska.
For Mead, our simulations suggest that dryland corn yields are not very sensitive to soil moisture status at planting. Note that these conclusions are based on crop model simulations and thus must be used to guide management decisions, along with past experience and any differences in soil properties compared to those specified in this study. Real-time soil moisture at various locations across the state can be checked at http://www.hprcc.unl.edu/awdn/soilm/.