Cold weather persists into March and is a blessing for some. Due to increased moisture in the fall and continuing into winter, the cold has frozen soil and solidified roads for field access. Fortunately, this means the moisture profile is quite saturated with ample moisture for the winter and the start of the growing season for summer crops. Unfortunately, this also means that the increased moisture is trapped within the sub-surface and is not evaporating. This increased soil moisture will be realized when the temperatures warm and soils thaw. Field conditions are anticipated to be difficult with excessive mud across a large majority of the state, especially in eastern and parts of western Kansas.
As the cold winter continues later than usual into March, this further delays melting. As this threshold is bumped later into the year, it approaches the spring rainy season, narrowing the available window for field work. Should spring moisture be delayed, then ample time would allow surface moisture to evaporate with warmer/drier conditions. However, the current spring outlook from the Climate Prediction Center puts emphasis on increased chances of above-normal precipitation (Figure 1). Should this occur, the window of feasible field work will likely be small, especially with reasonable soil temperatures for planting. These issues will be enhanced with additional moisture also forecasted as both rain/snow next week (March 11-13, Figure 2).
Figure 1. Climate Prediction Center precipitation outlook for March, April, and May.
Figure 2. Quantitative Precipitation Forecast (QPF) for the United States through March 14th.
Frost depths
Current frost depths across the state are estimated through soil moisture/temperatures to be as deep as 10 inches in the northern part of the state (Figure 3). As the cold has continued, the depth has increased southward and deeper into the soil. This will likely induce delays on planting due to the duration of warmer temperatures necessary to increase sub-surface soil temperatures. It will also increase flood concerns as the precipitation (see Figure 2) will not infiltrate but rather run off, agitating streams and rivers in the region.
Figure 3. Frost depth increases from February 28 (top image) to March 7 (bottom image), as estimated by the Kansas Mesonet using soil temperature and moisture measurements.
Even as producers are able to enter the field, risks of resulting soil surface damage are possible. This includes easier compaction due to wet soils that may stunt future plant growth and further trap sub-surface moisture. Producers also risk undesired damage and disruption to the soil surface. This will modify evaporation properties and create additional issues in the future for field operations. From the wheat perspective, it is not recommended to apply fertilizer when the ground is covered with snow or frozen. Once the ground thaws, it will likely be a while until growers can get field work done, and perhaps delaying the N fertilizer application can result in reduced yields, if this delay is significant.
A companion article in this eUpdate issue provides more information on fertilizer options: “Nitrogen loss potential during the winter and fertilizer options this spring”.
For more information on N management for wheat, check out the accompanying article in this eUpdate, “Topdressing wheat with nitrogen: Timing, application methods, sources, and rates”. Lastly, equipment damage and resulting downtime will not aid in productivity this spring.