Long-Term No-Till Impacts on Organic Carbon and Properties of Two Contrasting Soils and Corn Yields in Ohio

Tillage influence on soil properties and crop productivity depends on soil, crop, climate, and duration. Two long-term experimental sites with contrasting soils were selected to assess the influence of no-till (NT), minimum tillage (MT), and plow tillage (PT) under continuous corn (Zea mays L.) and corn-soybean [Glycine max (L.) Merr.] (CS) rotations on soil organic C (SOC) stock, bulk density (rho(b)), water-stable aggregation (WSA), aggregate tensile strength, penetration resistance, available water capacity (AWC), and corn yield. Experiments began in 1962 in northeast Ohio on a well-drained silt loam soil and in 1964 in northwest Ohio on a poorly drained clay loam soil. Results were compared with soil under an adjacent undisturbed woodlot (WL). The WL soils had the highest SOC content and stock. In the cultivated silt loam soil, stock was higher under NT (20.7 Mg ha(-1)) followed by MT (17.3 Mg ha(-1)) and PT (16.8 Mg ha(-1)) for the 0- to 10-cm depth. Soil rho(b) for this depth was lower under NT by 8 and 3% than PT and MT, respectively. The percentage of total WSA >2000 mu m in soil under NT (47%) was significantly higher than under MT (38%) or PT (34%). A similar trend was observed for the clay loam soil. Rotation also influenced soil properties. Corn yields were higher (3 yr) and lower (1 yr) during 5 yr for the silt loam soil under PT than NT and unaffected or slightly higher under NT for the clay loam soil. Long-term (47-49 yr) use of NT practices are highly sustainable and result in higher SOC and WSA, lower rho(b), and greater AWC content than MT or PT.