About 25 percent of the crop has reached the dough stage of grain development, so there are many acres still at risk for kernel abortion. Thus, rains now could still have a major impact on grain yield if it prevents more kernel abortion. Normally, we would not think of rains having this much potential impact, but this year is different.
Grain fill will proceed rapidly due to stress and high temperatures. A rapid grain fill is not good for kernel weight. Obviously, leaf death due to drought stress is also not good for grain filling because of the loss in photosynthetic capacity.
Where kernel set is reasonable, there will be risk of stalk cannibalization and stalk rots as drought stress continues through grain filling. Root health cannot be good (thus, reports of lodging with wind) and will certainly contribute to risk of poor stand ability and/or poor grain filling. Watch these fields as maturity nears. There is no reason to leave ears on the ground this year.
Multiple yield estimation opportunities exist this season and are important especially for grain marketing decisions. Here are the bullet points:
• Obviously absolute barrenness or plant death can be assessed any time. Assessment of kernel set success (abortion) can be made once dough state occurs.
• Kernel count estimation formula should wait until kernels have nearly reached black layer.
• Because late rains can impact your assessment of kernel size.
Grain moisture will likely drop fast this year; partly because of stress and premature BL (moisture at BL will likely be lower to begin with) and because of high temperatures and low humidity. Cob size, kernel size, and likely low moisture will cause harvesting challenges because of difficulties adjusting combine settings (risk of grain loss at header and out the back of combine). All the more reason to watch moisture content and standability; and not to delay harvest any longer than necessary.