Heavy Flooding Creates Major Challenges for Crop Producers

By Blake Jackson

Excessive rainfall and flooding continue to create major challenges for crop producers worldwide, with experts identifying flooding as one of the most harmful weather-related stresses after drought.

Researchers from the University of Missouri Extension are examining how saturated soils affect crop performance, nutrient availability, and long-term field productivity while offering guidance to help farmers reduce potential losses.

Studies led by soil scientist Gurbir Singh at the university’s Lee Greenley Jr. Memorial Research Farm, together with Gurpreet Kaur from the MU School of Natural Resources and other researchers, show that flooding and waterlogged soils significantly restrict oxygen in the root zone.

When soil pores fill with water, plant roots struggle to exchange gases, slowing growth and weakening crop health. Conditions are particularly difficult in Missouri’s claypan and floodplain soils, where drainage is naturally slow.

Researchers say crop damage depends on several factors, including temperature, flood duration, seed quality, and crop growth stage.

Corn is highly vulnerable during early vegetative growth stages between VE and V6, with oxygen shortages affecting roots within one to two days after flooding begins.

Extended flooding can reduce corn yields by as much as 20% due to poor nitrogen uptake and weakened root systems.

Soybeans can withstand short periods of saturated soils during early development, but prolonged flooding still causes serious stand losses and yield reductions.

Experts estimate soybean fields may lose one to three bushels per acre for every day fields remain flooded during the V2 to V5 stages. Uneven plant stands and damaged roots can also affect crop performance later in the season, especially if dry weather follows.

Waterlogged soils also increase nitrogen losses through denitrification, runoff, and leaching. Researchers recommend split nitrogen applications to reduce risk and improve fertilizer efficiency.

Farmers are also encouraged to scout fields for diseases favored by wet conditions, including Pythium, Phytophthora, Rhizoctonia, sudden death syndrome in soybeans, and Fusarium head blight in wheat.

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