Long-term tillage and drainage influences on soil organic carbon dynamics, aggregate stability and corn yield

Labile pools of soil organic carbon (SOC) and nitrogen (N) are affecting the carbon (C) and N fluxes in the terrestrial soils, whereas long-term C and N storage is determined by the long-lived recalcitrant fractions. Tillage and subsurface drainage influences these pools; however, the effect of these systems on poorly drained soils may be different. Therefore, the present study was conducted on a field experiment, established at the Waterman Farm of the Ohio State University in 1994. Specific objectives of the study are to assess the influence of no-tillage (NT), chisel tillage (CT) with drainage (TD) and non-drainage (ND) management under a continuous corn (Zea mays L.) system on SOC, C fractions (heavy and light), and water stable aggregates (WSA). Data from this study showed that the SOC stock for the NT was 25, 37 and 32% higher for the 0-10, 10-20 and 40-60cm depths, respectively, as compared to that under CT system. Tillage significantly influenced the light fraction (LF) and heavy fraction (HF) of carbon. The NT system increased LF and HF by 10 and 12%, respectively, compared to CT for the 0-10cm depth. Eighteen years of NT management decreased soil bulk density and improved macroaggregates and mean weight diameter compared to that under CT system. Drainage impacts on soil parameters were negligible, and may be partially due to the reason that the corn-corn cropping system may not have sufficiently improved the soil properties between the two tillage systems. In general, drainage improved porosity and the corn yield. It can be concluded that NT with subsurface management improves SOC dynamics and promotes aggregation and corn yield as compared to that with CT system.