Slope position and erosional effects on soil properties and corn production on a Miamian soil in central Ohio

Corn (Zea mays L.) growth and yield were related to surface soil properties and slope position on field runoff plots established on a Miamian (Typic Hapludalf) soil with 5 to 6% slope in central Ohio. The 3-year study conducted from 1988 through 1991 involved four treatments designed to create different magnitude of soil erosion: (1) disk-plowing up and down the slope (DP), (2) disk-plowing up and down the slope followed by protective netting suspended about 0.15 m above the soil surface (PN), (3) uncultivated bare fallow without any vegetation cover followed by removal of topsoil to 0.2 m depth (R), and (4) uncultivated fallow with natural vegetation cover followed by plowing (F). These treatments were imposed during 1988 and 1989 on runoff plots of 1.8 X 15 m, and all treatments were replicated three times. Surface soil of the R treatment was removed to 0.2 m depth in May 1990. From there on, all plots were plowed and planted to corn. Measurements of soil properties and corn growth were made at 3 slope positions in each plot, corresponding with upper, middle and lower slopes. Soil erosion was the most severe, clay content the highest, and aggregation the least in the middle slope position. Corn growth was significantly affected by slope position, and mean corn height 10 weeks after planting was 13.5% more in the lower compared with other two positions. The highest biomass production, greater nutrient uptake, and highest corn grain yield were observed in the lower slope position. During 1990 with normal rains, mean corn grain yield in the lower position was 36.9% and 56.8% more than upper and middle landscape positions, respectively. During 1991 with below normal rains, mean grain yield in the lower position was 3.14 and 3.70 times more than that of the upper and middle positions, respectively.