A COMPARISON OF SLIT TILLAGE AND SUBSOILING IN A SUBSURFACE HARDPAN SOIL

Sorghum was grown for four years (1986 t o 1989) on plots that were slit tilled, subsoiled, and n o tilled. Corn was grown for three years (1990 t o 1992) following the tillage t o access its residual effects. Draft was measured for slit-till and subsoil implements the first year of the study. Pits were dug each year t o assess root growth. Soil strength was measured the last three years. Draft requirements for the slit tillage implement was 75 % of that for a comparable subsoiler. The slit tillage implement disrupted the soil to the top of the pan and cut a eighth of an inch slit through the pan. The subsoiler disrupted the soil t o the bot tom of the subsoil pan. When the plots were tilled, slit tilled and subsoiled treatments both outyielded n o tillage. Sorghum yields for slit tillage were slightly higher than subsoiling. After tillage ceased, subsoiled treatments outyielded n o tillage. Yield for the slit tillage treatment was about the same as for n o tillage. Soil strength readings showed that more of the profile was disrupted below the r o w for subsoiled t reatments than fo r slit-t i l lage treatments. Few slits could be found in the pit walls after three years. With lower energy requirements than subsoiling and comparable yield, slit tillage has promise for this southeastern Coastal Plain soil as long as regularly scheduled tillage is required. Slit tillage management warrants further investigation