Standing Water and Wet Soils

Kat Caswell, Washington and Weld Extension Agronomist

Good news, according to the UNL Drought Monitor, drought conditions are improving across northeast Colorado. Aside from a few storms, Weld County has been receiving a trickle of rain each day, allowing time for water to move into the soil profile, without leaving any standing water. In other areas, of NE Colorado, storms producing greater rainfall in a short period of time are leaving standing water in fields, and in some cases running off fields.

Slower rainfall can be of benefit to the wheat crop. Wheat conditions have varied field to field based on planting timing. Thinner fields with poorer stands will benefit from the rainfall but are unlikely to yield as well as those with better fall stand establishment. Areas with excessive amounts of moisture may have a negative impact on kernel development, reducing yield.

Wheat can tolerate approximately 24 hours of standing water before there is significant damage. The level of damage will depend on the growth stage of the wheat, but in general, will increase the risk of lodging. With the likely pressure of wheat-stem sawfly, monitoring wheat lodging and considering harvest methods should be planned for.

Cooler moist soils create a greater risk for disease pressure. Root rot has been observed in Kit Carson County, as reported in the Wheat Disease Newsletter.  Although stripe rust has not been observed, wheat fields near I70 are experiencing outbreaks of leaf rust.  Treatment is similar for both rusts.  Continue to scout fields for any new diseases and monitor the Wheat Disease Newsletter for updates.

Corn planting has been slightly delayed this year with the cooler soil temperatures. Standing water on a recently planted corn can kill newly emerging seeds, cause uneven plant emergence, increase disease risk, or nutrient accumulation problems in the stand. Corn seedlings in wet soil are likely to develop only a shallow root system, reducing their ability to access moisture lower in the soil profile during hotter months. Planting into wet soils will lead to soil compaction from equipment and sidewall compaction in the furrow. Sidewall compaction will inhibit root growth, restricting the plant’s ability to access nutrients and moisture. Cool and wet soils can reduce emergence and result in an even stand.

If there is standing water in a recently planted field, wait for the water to drain before scouting or making the decision to replant. Evaluate field conditions before planting any crop. Soils should be at least 50 degrees Fahrenheit at a 2 inch depth. Clay soils that are too wet will produce water when squeezed, much like a sponge. Dryland corn still has limited window for planting remaining, but irrigated fields that are not yet planted should consider changing to a shorter season variety or planting a different crop.

Soils that continue to have standing water or are too wet past the planting windows for common crops still have options for a later planting with a substitute crop Residue management is important for drought resilience and managing heavy rainfalls. Cover crops and annual forages can be planted later into the summer. Both will produce residue and reduce the risk of soil erosion than if a field is fallowed.

With the cool, wet spring, regular scouting of field conditions will be important for any crop. Waiting for soil temperatures and moisture to be adequate is important for any planting, but if conditions are not met for your intended crop, consider other crop options. Fields with standing water should wait until the water has drained and evaluate each field’s stand before making replanting decisions.

Contributions from Ron Myer, GPA Agronomist