Long-Term Tillage and Crop Rotation for 5 Decades Impacts on Fertility of Two Contrasting Soils in Ohio.

To evaluate the impact of tillage and crop rotation on soil fertility, we analyzed soil organic carbon (SOC), total N, extractable P and K in the soil profile after long-term (50 yr) of continuous tillage and crop rotation management at two experimental sites (Wooster and Hoytville, Ohio). The tillage management included no-tillage (NT) and chisel-tillage (MT), and the crop rotation included continuous corn (CC) and corn after soybean (CS). The SOC, total N, and extractable P and K concentrations were greater for NT than for MT in the 0-10-cm soil layer, but reversed results in the 10-20-cm layer. There were generally no differences in the 20-40- and the 40-60-cm soil layers. For the crop rotation comparison, there were generally no differences in SOC, total N, extractable P and K concentrations in any of the soil layers. This study indicates that application of NT can effectively accumulate C, N, P, and K only in the surface 0-10 cm soil layer.