Ponded fields

Quite a week weather-wise, measured rainfall over the last 7 days currently stands at over 3 inches as storm fronts repeatedly rolled across central DeKalb County. Rainfall in Northern Illinois has ranged from slightly over 2 inches to 8+ inches. In some areas the ponding persists in crop fields. What damage is done and how long can the plants survive under these conditions? Flooding reduces yields by decreasing stands, and slowing dry matter accumulation or both. The most obvious effect of flooding is the lack of oxygen for the roots. Research has shown that oxygen concentration can be close to zero after 24 hours in flooded soil. Without oxygen, the plant can’t perform important functions like respiration, critical for plant growth. Still, predicting the survivability of crops in saturated soils is challenging and highly variable. But here is what we know;

The extent of injury is dependent on

• Length of ponding, how long is the ground saturated with moisture?
• Stage of development of the crop, corn beyond V6 is much more likely to survive in comparable situations than younger corn, As corn matures and the growing point elevates it less prone to damage.
• Air and soil temperatures. Cooler temperatures prolong survival of submerged crops.
• Crop – corn is more susceptible to flooding damage than soybean.
• Even if the crop is not killed yield decreases and a greater potential for disease are likely.

This week Dr. Emerson Nafziger shared that the University of Illinois will be continuing its research and update on crop removal rates of nutrients. With funding from the Nutrient Research & Education Council (NREC) a new project is starting in 2014 to try to get a better idea for how much nitrogen (N), phosphorus (P), and potassium (K) are contained in harvested grain of corn, soybean, and wheat. While this seems like a simple thing to measure, we expect things like yield level, soil, crop variety, and growing season weather may affect nutrient levels. A number of samples state wide will be needed to accurately assess nutrient removal. Before getting to corn and soybean harvest we plan on starting with wheat. Realizing wheat acres are limited in northern Illinois, volunteers to send in samples are more critical. Mailers and postage are available for the grain samples until the funds run out. For additional information visit the Illinois Bulletin to access Emersons report.

http://bulletin.ipm.illinois.edu/?p=2297

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Posted by Russel Higgins at 1:47PM on 6/23/2014