Tillage Studies with Corn on an Ohio Lakebed Clay Soil

Abstract A 3‐year tillage study with corn was conducted on Hoytville silty clay, an extensive soil in the old glacial lakebed which covers portions of Ohio, Indiana, and Michigan. The treatments were fall plowing, spring plowing at shallow and normal plow depths, spring plowing of wet soils, and surface tillage after spring plowing which gave two degrees of seedbed “fineness”. Treatment brought about a wide range of surface conditions on plots following alfalfa or corn. Fall and shallow plowing have usually resulted in fine seedbed and in rapid emergence. Coarse seedbeds and less rapid emergence were obtained by spring plowing at normal plow depths. Shallow and wet plowing resulted in lowest soil moisture contents. The treatments resulted in significant differences in soil porosities and nitrogen contents following alfalfa but not following corn. Following alfalfa, spring plowing at normal plow depths brought about highest soil porosities and greatest leaf nitrogen contents; while fall, wet, and shallow plowing were associated with lower porosities and nitrogen. The treatments had no effect on phosphorus contents and affected potassium contents only during a drouthy season. Corn yields were reduced during a drouthy season by spring plowing with maximum seedbed fitting, and by shallow and wet plowing. Lowest yields were obtained from the treatments which result in lowest soil moisture contents. There were no significant yield differences during 2 years of better rainfall distribution.