Soil Temperature at the 4-inch depth is important to crop establishment even though seed placement is usually at depths of less than 2 inches. Soil temperature of below 50F is important to responsible fall anhydrous application. The estimated county soil temperature in Iowa is derived from observations at 16 locations extrapolated to the 99 Iowa counties. The estimated county temperatures may be obtained at: http://mesonet.agron.iastate.edu/agclimate/soilt.php values in “red” are measured temperatures all others are estimates based on the observations.
Observed Soil Temperatures at other depths (4”, 12”, 24”, 48” ) can be viewed by selecting the depth from :
http://mesonet.agron.iastate.edu/agclimate/#tmpf
Freezing to depth in Iowa soils is most common when snow cover is scant during the coldest period of winter. Snow cover of 12” or more often results in reduced penetration of freezing temperatures in the soil.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on January 11, 2017. The information contained within may not be the most current and accurate depending on when it is accessed.