Flood risks - wheat and alfalfa survival

By Scout Nelson

Flooding and prolonged soil saturation can severely impact crop health and yield, particularly for wheat and alfalfa. Factors such as air temperature, plant development stage, duration of submersion, and pest pressures play crucial roles in determining the extent of damage.

Wheat: During the critical headed to flowering stages, wheat is especially vulnerable. In saturated conditions, wheat may experience lodging due to weakened stems, leading to kinking or breakage.

Submersion for more than 24 hours during flowering can interfere with pollination and kernel development, potentially resulting in significant yield losses ranging from 4% to 90%, depending on the duration of waterlogging and the variety's resilience. Affected wheat may exhibit shriveled kernels and reduced test weights.

Alfalfa: Alfalfa shows a notable reduction in growth when flooded, particularly if the flooding occurs shortly after cutting. Diseases like root and crown rot can devastate alfalfa stands if submerged for more than a few days. Post-flooding, it's vital to assess the health of alfalfa roots; healthy roots should appear creamy white, while brown or discolored roots indicate damage.

If large patches of the field are affected, consider planting warm-season annuals like millets or sudangrass to maintain forage production, as reseeding alfalfa in the same areas could fail due to autotoxicity.

In cases of flooding, alfalfa stands that weren't recently cut can survive up to two weeks without significant damage. After waters recede, it's essential to allow the soil to dry adequately before attempting any harvesting to prevent further damage to the plants.

Delaying the next alfalfa cut can also give the plants more time to recover, enhancing their chances of survival and productivity.

Photo Credit -gettyimages-jj-gouin