We are once again providing a soil temperature overview in the C.O.R.N. Newsletter through April-May 2020. The College of Food, Agricultural, and Environmental Sciences (CFAES) Agricultural Research Stations located throughout the state have two- and four-inch soil temperatures monitored on an hourly basis. Our Western site in Clark County is not available this year. Therefore, we are supplementing data from western Ohio with data from Darke and Greene Counties. These sites (noted by an asterisk on Figure 1) report minimum (morning) soil temperatures. The other sites are reported on Figure 1 as a daily average.
Figure 1: Average daily air temperature (red), two-inch (green) and four-inch (blue) soil temperatures for spring 2020. Map of locations in bottom right. Soil temperatures are minimum temperatures for Versailles and Xenia and daily average for other sites.
Figure 1 shows that two- and four-inch soil temperatures have varied significantly in response to large swings in air temperature. Early in the week, daily average air temperatures warmed well into the 60s for southern sites (Versailles, Xenia, and Piketon) and to near 60 for northern sites (North Central and Wooster). In response, soil temperatures warmed into the mid-50s to low-60s across the state. Cooler weather later in the week caused soil temperatures to cool into the upper-40s to low-50s with a small rebound over the weekend. These soil temperatures are near their 5-year averages for North Central and Piketon but a bit cooler than the 5-year average at Wooster (by ~2°F). The current weather forecast calls for below to much-below average air temperatures over the next 5-7 days. Soil temperatures are likely to remain steady or cool slightly throughout the upcoming week.
Figure 2 (left) shows that plenty of rainfall fell across much of the state for the week ending April 12, 2020. Totals of 1.5-3 inches were verified from west central Ohio southeast through our far southeastern counties (dark green and yellow shadings). Much drier conditions were experienced in southwest Ohio. As a result, current calculated soil moisture ranking percentiles (right) dropped across this part of the state. However, soil moisture increased across Ohio’s eastern counties. Much of the state remains above the 80th percentile with the greatest percentiles noted across northeast Ohio.
Figure 2: (Left) Precipitation estimates for the last 7 days ending on 4/12/2020. Figure provided by the Midwest Regional Climate Center (https://www.mrcc.illinois.edu). (Right) Calculated soil moisture ranking percentile for April 12, 2020 provided by NOAA's Climate Prediction Center (https://www.cpc.noa.gov/).
For more complete weather records for CFAES research stations, including temperature, precipitation, growing degree days, and other useful weather observations, please visit https://www.oardc.ohio-state.edu/weather1/.