Managing Early Season Soil Temperatures in the Northern Corn Belt Using Configured Soil Surfaces and Mulches

Soil temperatures in the northern Corn Belt are often too low at planting time to allow optimum germination, emergence, and early seedling growth. Crop residues, which are beneficial for erosion protection or are the result of minimum tillage, generally retard the rate of drying and warming of the seedbed. We found that ridged soils dried faster starting at the peak of the ridges and continuing down their southerly exposed slopes. Maximum seedbed temperatures occurred either under the ridge peak or under the southerly exposed slope. The time of the diurnal maximum temperatures depended on the slope aspect. For example, a southeast‐facing slope reached maximum temperature over 2 h earlier than a southwest‐facing slope, although the southwest slope reached a higher maximum temperature. Mulch decreased daytime soil temperatures, but a combination of mulch and ridging offset this temperature decrease so that there was no difference between a seedbed temperature under a mulch‐covered ridge and a conventionally tilled soil without mulch. Mulch with ridging provides a limited means of managing soil water and soil temperature in the seedbed.