Soil moisture is an important variable controlling multiple hydrological processes (e.g. runoff, flooding, recharge of surface water reservoirs, etc.) and agricultural management decisions (e.g. crop rotation, tillage practices, planting and harvesting date, timing of fertilizer application, and field traffic conditions).
At this time of the year, farming operations across Kansas are concentrated around wheat planting and summer crop harvesting, two activities significantly affected by soil moisture conditions.
One way to assess the current state and implications of root-zone soil moisture conditions across the state is by using information from the recently launched Soil Moisture Active Passive (SMAP) satellite mission by NASA. The sequence of maps in Figure 1 clearly shows a mild drought in western Kansas and signs of excess soil moisture in central Kansas (particularly near Wichita area), a strong dichotomy that closely matches the precipitation pattern in Figure 2.
Figure 1. Kansas rootzone soil moisture dynamics from October 1-17, 2016. Many Kansas soils can usually hold a maximum of 50% soil water content water (saturated conditions).
Figure 2. Statewide cumulative precipitation from October 1-17, 2016. A value of 25 mm is approximately equivalent to 1 inch.
Wheat: The wet conditions throughout mid-October in the central and eastern part of the state ensured good stand establishment despite causing a slight delay for wheat sowing compared to 2015. In southwest Kansas, producers who started sowing in early September took advantage of available soil moisture and consequently also have a good stand. However, producers in southwest Kansas who waited for the optimal sowing window had to dust-in the crop, which resulted in several fields with sub-optimal stand establishment. Many fields in southwest Kansas sown after October 10 have not yet started to germinate due to the lack of soil moisture.
Summer crops: Overall, late-season wet conditions slowed down harvesting progress in summer row crops. For corn, late-season precipitation increased fungal colonization of corn ears (e.g. Diplodia issues), and reduced final test weight and grain quality. For both soybeans and sorghum crops, wet conditions are affecting the drydown grain rate and final maturity.
Andres Patrignani, Soil Water Processes Agronomist
andrespatrignani@ksu.edu
Ignacio Ciampitti, Crop Production and Cropping Systems Specialist
ciampitti@ksu.edu
Romulo Lollato, Wheat and Forages Specialist
lollato@ksu.edu
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