While we are seeing a little bit of rain throughout much of the eastern half of the state, the national drought monitor updated southern Wisconsin to D1 last Thursday, putting it in the moderate drought category. How did we get here, to suddenly experiencing a ‘flash drought’? I say suddenly because Wisconsin just experienced the wettest winter on record before rolling into the fourth driest May on record. The long and short of it is that a high-pressure dome has parked itself over Canada driving out moisture and bringing generally sunny skies–unless the resulting winds drag along Canadian wildfire smoke like last week. While the forecast is that this dome will break apart by the end of this week, where should your level of concern be for this year’s crop growing season?
Soil moisture, corn, and soybeans
Generally, we are in okay shape. Most farmers had good soil moisture for planting both corn and soybeans, with the week ending on May 30 showing adequate soil moisture for 53% of the topsoil in the state, with 90% of the corn and 82% of the soybeans already planted. Beyond the initial imbibition of water and subsequent germination, corn and soybeans do not require much water in these early vegetative stages, and moderate drought stress does not have a huge impact on yield if the crops can make it to emergence. The saturated soils we had at the beginning of May have led to fairly normal soil moisture levels down to 3 feet, while the upper eight inches are in the 10-20 percentile of historical records, i.e., much drier than average. Our growing crops’ roots will chase that water down into the deeper levels of the soil. And, importantly, our soils still had moderate soil moisture during the summer’s first heatwave at the end of May. Temperature is a greater stressor to young crops than moisture. As temperatures climb past 90°F, evapotranspiration rates rapidly increase, crop growth slows, and the roots struggle to dig deeper for trapped moisture. Thankfully, the heat has quit for a bit and we can a little more calmly pray for more rain. While the lack of rain is concerning, now is not the time to panic; the most critical time for adequate soil moisture for corn is late vegetative to silking and pod filling in soybeans.
What about wheat?
While winter wheat water use peaks right about now and in the weeks ahead during grain filling, dry weather is not as worrisome and can actually be helpful. Having lived through the Wisconsin winter, wheat is a tough crop with roots that can go down almost 7 feet. As I said before, even though our topsoils are abnormally dry, our subsoils are well within normal soil moisture. Why are dry conditions helpful for growing wheat in Wisconsin? Dry conditions lead to lower and more uniform grain moisture at harvest time, speeding up harvest and allowing farmers to forgo additional post-harvest drying down to the magical 13.5% moisture content. Furthermore, some of the biggest economic risks for wheat in Wisconsin, Fusarium Head Blight or scab and lodging, are far less likely in dry conditions, and disease incidence in the state is very low.
Source: wisc.edu
Photo Credit: Kinze Manufacturing
Categories: Wisconsin, Crops, Weather