High temperatures and lack of rain this month have left many farmers in the Corn Belt concerned.
Illinois state climatologist Trent Ford says that evapotranspiration is to blame.
According to Ford, “Evapotranspiration is the combined effect of evaporation directly from the soil, so water just leaving the ground directly to the atmosphere, and transpiration which is the same sort of process of water moving from the surface to the air but it’s through the plant itself. One of the biggest drivers of evapotranspiration is the temperature of the air, and that’s really where it comes down to is, how much the air is demanding from the crop that moisture and how quickly it will evaporate that moisture. That really determines how much evapotranspiration we’re going to have. So, the reason we’re seeing these very high evapotranspiration values with up to maybe three-tenths of an inch is because of that high temperature.”
Ford says that the high rates of evapotranspiration we are seeing now, coupled with high temperatures, could lead to flash droughts with almost immediate impacts.
“It really just depends on all the conditions on the ground, but we can see a crop that looks very healthy go to something that’s showing moisture stress, not just heat stress but moisture stress, in a period as quick as up to seven to ten days depending on soil moisture reserves,” he adds.
While the heat is not going anywhere soon, it may be shifting its coverage area in the next week or so.
“The heat is going to shift around just a little bit as we start off this week and move into the middle part of the week. We’re kind of focused back across the mid-South and into the central and southern High Plains. But, as we move toward the end of the week, we are going to be looking at that heat shifting a bit to the east, more into the eastern Corn Belt, the mid-Atlantic, and the southeast as we head into the weekend and beyond. Day-to-day some slight variations, but the general overarching theme is the hot weather central and southern Great Plains eastward,” according to Brad Rippey.
