Axle load and tillage effects on crop yields on a Mollic Ochraqualf in Northwest Ohio

Effects of axle load and tillage methods were studied for four crops grown on a clayey soil in the lake-bed region of northwestern Ohio for 7 consecutive years from 1988 to 1991. Three tillage methods were no-till (NT), chisel plough (CP) and mouldboard ploughing (MP). Split-plot axle load treatments were control, 10 Mg axle load and 20 Mg axle load. Axle load was created using a single axle grain cart either half full (10 Mg) or full (20 Mg). Maize (2ea mays), soybeans (Glycine max), oats (Avena sativa), and sugarbeet (Beta vulgaris) were grown in 3-year or 2-year rotation sequences. Axle load treatments had a significant effect on crop yield. Considering average yield for the 3-year rotation over all tillage treatments and 7 seasons, mean maize yield was 7.2 Mg ha(-1) for control, 6.0 Mg ha(-1) for 10 Mg axle load, and 5.4 Mg ha(-1) for 20 Mg axle load. Mean maize yield in 2-year rotation was 7.1 Mg ha(-1) for control, 6.1 Mg ha(-1) for 10 Mg axle load, and 5.4 Mg ha(-1) for 20 Mg axle load. Soybean grain yield in the 2-year rotation was 2.4 Mg ha(-1) for control, 2.2 Mg ha(-1) for 10 Mg axle load, and 1.9 Mg ha(-1) for 20 Mg axle load. Mean soybean grain yield for the 2-year rotation was 2.6 Mg ha(-1) for control, 2.0 Mg ha(-1) for 10 Mg axle load, and 1.6 Mg ha(-1) for 20 Mg axle load. Mean oat grain yield, based on the average of all tillage treatments over the 7 seasons, was 2.6 Mg ha(-1) for control, 2.1 Mg ha(-1) for 10 Mg axle load, and 1.8 Mg ha(-1) for 20 Mg axle load. Crop yield was also affected by the tillage treatments. Mean maize grain yield was 5.8 Mg ha(-1) for NT, 6.5 Mg ha(-1) for CP, and 6.3 Mg ha(-1) for MP in the 3-year rotation compared with 6.4 Mg ha(-1) for NT, 6.0 Mg ha(-1) for CP, and 6.1 Mg ha(-1) for MP method in the 2-year rotation. The average soybean yield in 3-year rotation was 2.1 Mg ha(-1) for NT, 2.1 Mg ha(-1) for CP, and 2.2 Mg ha(-1) for MP methods. Mean oat grain yield was 2.3 Mg ha(-1) for NT, 2.3 Mg ha(-1) for CP, and 2.0 Mg ha(-1) for MP method. Tillage methods had no significant effect on sugarbeet yield, which was 10.8 Mg ha(-1) for NT, 16.0 Mg ha(-1) for CP, and 14.0 Mg ha(-1) for MP methods.