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.
Our growing season follows a warmer than average winter. Winter (December 2019 – February 2020) air temperatures averaged 2-8°F above average compared to the climatological normal (1981-2010). This warmth continued throughout March as well, with temperatures 4-8°F (west to east) above average. As a result, soil temperatures are about 10°F warmer than the same date in April 2019.
Figure 1 shows that two- and four-inch soil temperatures at North Central, Wooster, and Piketon cooled a bit at the end of March and beginning of April, but all stations show conditions have since turned around with progressively warmer weather this week. Our northern stations (Versailles, North Central, and Wooster) show soil temperatures generally in the upper 40s-low 50s °F while our southern stations (Xenia and Piketon) report soil temperatures in the low to mid 50s °F. Soil temperature may warm slightly early this week before cooler weather late this week and next week likely slows warmth.
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 2 shows a model-based analysis of soil moisture for April 4, 2019 (left) and April 5, 2020 (right). Currently, soil moisture is running in the 80th percentile or greater meaning that current conditions are wetter than at least 80% of all years on this date in the historical record (1948-present). Locations in northeast Ohio are running in the 90-95th percentiles. While moisture is high, Ohio is generally in better shape (drier) than at this same time last year, when much of the state was in the 95th or 99th percentile.
Figure 2: Calculated soil moisture ranking percentile for April 4, 2019 (left) and April 5, 2020 (right). Figure provided by NOAA's Climate Prediction Center (https://www.cpc.ncep.noaa.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/.