2025 Pre-harvest Ponderings
Nicole Luhr
Water and Cropping Systems Extension Educator
The combines will be rolling through the fields at full throttle soon to get the crops harvested. Rain throughout the summer was beneficial this year in regard to soil moisture which resulted in little to no irrigation in the northeast part of the state. Before getting into the heat of harvest, here are a few things to point out.
Developmental Delays
Harvest is later than average this year. Have you wondered why? There are several elements that could factor into this. One of them is how high the relative humidity was throughout the summer. Relative humidity influences turgor pressure (turgidity), which is the measure of the pressure between the plant cell membrane and the cell wall. Increased turgor pressure indicates decreased flow of water into and out of the cell. When humidity is high, transpiration is slowed. This decreases water movement throughout the plant, leading to less nutrient uptake and thereby delaying plant development.
Another factor could be having less solar radiation from overcast skies or thick smoke in the air. The combination of solar energy and water allows plants to fix carbon dioxide from the atmosphere and create carbohydrates. Carbohydrates are what provide energy for the plant to develop. The less solar radiation, the less energy the plant puts toward developing to maturity.
Results of Disease and Insect Pressure
Corn fields with a high disease presence, less favorable growing conditions, or where fungicide wasn’t applied may have standability issues due to stalk rot and general decreased stalk quality. High disease fields will also have quicker grain dry down because the increased disease pressure may cause premature formation of black layer.
If a soybean field was highly infected with white mold, that field should try to be harvested last to avoid spreading the sclerotia (the spores that overwinter the pathogen). The same goes for the fields with high levels of sudden death syndrome where they patches should be done last to avoid spreading the pathogen. On the other hand, if the field was infested with dectes stem borer or soybean gall midge, those fields should be harvested first to avoid additional lodging that could happen.
Disease pressure may also impact grain development and lead to various molds. Lower quality grain in general should not be mixed in storage with higher quality grain since fungi can continue to grow in storage.
This year will end with some different circumstances, but on a positive note, yields are expected to be higher than normal. Anticipated yields for soybeans are looking to be anywhere from 70 to 90 bushels an acre. Corn fields with fungicide could range around 210 to 250 bushels an acre while the fields without fungicide could be 20 to 40 bushels lower.