James Adkins, Extension Engineer, adkins@udel.edu
Field Corn
Wednesday night’s rain provided temporary relief for northern Delaware. The forecast for the next few days predicts significant rainfall statewide. Evapotranspiration (ET) for corn planted on April 15 averaged 0.26 inches per day over the past week, while corn planted on May 12 averaged 0.25 inches per day.
Looking ahead over the next 5 days, ET is expected to decrease to 0.2 inches per day on Thursday and Friday (7/11 & 7/12) due to cloud cover. However, Monday’s forecasted heat will increase ET to 0.31 inches per day. Systems that cannot meet these daily demands should run at maximum capacity to maintain soil moisture, though yields may be somewhat limited. In deficit irrigation scenarios, avoid the temptation to apply very little water frequently. Instead, aim for applications in the range of 0.4 to 0.7 inches to optimize crop water use and minimize evaporative losses.
Soybean
Full-season beans, which have been flowering for 1-2+ weeks, will require regular irrigation. If beans have recently started flowering and you haven’t irrigated and received substantial rainfall, you’ll need to replenish a soil moisture deficit of 1.5+ inches before adopting a 0.25 inches per day approach. Achieving this is challenging with most center pivots due to limited capacity. I recommend targeting 0.4 inches per pass until significant rain is received. Double-crop beans should focus on maximizing vegetative growth to establish canopy quickly and will likely need irrigation from planting onwards. Recently emerged beans are forecasted to use 0.1 inches per day in the coming week.
General
The Delaware Irrigation Management System (DIMS) has been updated to be mobile-friendly. This system automatically tracks crop water usage using data from the DEOS weather station network and provides a forecast and prediction model for planning irrigation over the next 5 days. To use this free system for scheduling irrigation, visit DIMS Website.
In the event of irrigation well failure, an emergency well replacement process is available through DNREC. However, if you do not have a water allocation in place, your replacement will be delayed by the mandatory 2-week advertising period. For more information on water allocations, contact Patty Murray of the DNREC Division of Water at patricia.murray@delaware.gov or 302-739-9948.