EFFECT OF TILLAGE SYSTEMS ON THE EMERGENCE DEPTH OF GIANT (SETARIA-FABERI) AND GREEN FOXTAIL (SETARIA-VIRIDIS)

The effect of tillage systems on depth of emergence and densities of giant and green foxtail under different environment and cropping conditions were evaluated from 1985 to 1987 at Arlington, Hancock, and Janesville, WI. Mean emergence depths in no-till were the shallowest, followed by chisel plow and conventional tillage at each location. At least 40% of the giant and green foxtail plants emerged from the upper 1 cm of soil in no-till compared to about 25% in chisel plow and less than 15% in conventional tillage. As many as 25% of the plants emerged from greater than 4 cm in conventional tillage compared to about 10% in chisel plow and less than 5% in no-till. Seedlings emerged from greater depths in a loamy sand than in a silt loam soil regardless of tillage system. At Arlington, green foxtail was the dominant species in conventional tillage, while giant foxtail dominated in chisel plow and no-till. Foxtail densities were greater in chisel plow and no-till than in conventional tillage at all three locations.