When wet conditions lead to harvest delays
What effect do late-season wet conditions and even flooding have on corn and soybeans as we wait for field conditions to improve and harvest to resume?
Wet soil conditions, pressure from corn rootworm and European corn borer, and plants attempting to a fill large number of kernels per ear can set some fields up for potential stalk rot problems. Although some of the fungi causing stalk rots are a player in the natural process of recycling nutrients and organic matter back into the soil, decay of stalk pith prior to harvest can increase lodging potential. Harvest delays increase the chance of lodging due to stalk rots and lodged plants decrease harvestability, leading to ears being left in the field.
To check for stalk rot, stalks can be split (check for stalk tissue disintegration) or squeezed between your fingers (check if stalks are easily crushed) or pushed from vertical (severely stalk rotted plants will kink or lodge). Fields with stalk quality issues should be targeted for harvest as soon as is feasible because of increased lodging potential. Fields with heavy infestations of European corn borer should also be targeted for harvest as soon as is feasible.
Corn grain quality can also be a concern when wet conditions delay harvest. Be on the lookout for ear rots and if grain becomes molded, be sure to test for mycotoxins prior to feeding to livestock.
In soybean fields where pods were submerged by standing water for a significant time period, seed quality is a concern. Wet conditions combined with warm temperatures increase the risk of damage from fungal pathogens. If areas were submerged for several days, stems may weaken or rot, increasing the chance of lodging and harvest losses. Prior hail damage or previous stem diseases may predispose plants to further injury. Pod shatter prior to harvest is also of concern, especially if soybeans go through several cycles of drying and re-wetting.
If soybeans were submerged in areas of the field, consider segregating these potentially lower quality soybeans. Segregation may be particularly beneficial if soybeans were intended to be sold to a specialty market where premiums are based on soybean quality.
Delayed harvest will also influence the ability to conduct fall tillage operations and fertilizer applications. The main focus is, of course, to get crops out of the field. As field conditions improve and harvest resumes, keep an eye on crop status when deciding which fields to harvest next to help maximize crop quality and yield.