By Andrew Kness
The last time many areas of the state picked up more than 0.5” of rain was over 30 days ago and we are currently running about 8-10” short on precipitation for the year. Couple that with an abnormally dry winter, our soil moisture is getting depleted. Fortunately we have also been stuck with unusually cool temperatures, which I think has held off the major drought conditions; at least for now.
You may be wondering what early drought conditions means for crops, and the answer is it depends on how long conditions remain droughty.
For rainfed field crops, such as corn and soybeans, early season droughts can actually be beneficial, assuming it is not so severe that plants die and rain eventually arrives. Typically in Maryland we are complaining about the opposite problem come spring planting—too wet, which can inhibit root growth causing shallow-rooted plants and can also cause root-rotting diseases leading to total plant death. However, a little bit of moisture stress during early vegetative growth, say V2-V8 in corn, can actually benefit the crop later in the season because the plants will be much deeper rooted (assuming there’s no hard pan) and can access moisture when they most need it, during tassel and grain fill. Research indicates that drought stress before V13 has very little, if not any, affect on yield. However, from V13 to silking, drought stress will significantly affect corn grain yield.
Fortunately most of the young crops are still hanging on ok, and have yet to exhibit wilting. As long as we can avoid that condition and get some much-needed timely rains, we still have potential for big yields. If droughty conditions persist into late vegetative and reproductive stages, then we should expect reduced yields.
For soybeans, as long as the plants are not showing signs of wilting they should still have decent yield potential. Even if soybeans do start showing signs of drought stress in early vegetative growth, they can still rebound with near full yield potential as long as moisture returns around R1. The most critical time for soybeans to have adequate moisture is R4-R5; I sure hope we are not still talking about drought come August!
This article appears in June 2023, Volume 14, Issue 3 of the Agronomy News.
Source : umd.edu