Abatement of Nitrate Pollution in Groundwater and Surface Runoff from Cropland Using Legume Cover Crops with No-Till Corn

摘要

Agricultural practices can have a significant impact on water quality. The effects of leguminous winter cover crops on leaching of nitrates from soil have been investigated in the project. Legume cover crops, by fixation of atmospheric N, can reduce the amount of fertilizer N required to produce summer grain crops. The methods initially used to evaluate cover crop effects on nitrate transport included suction probe lysimeters and measurement of nitrates in soil samples collected to a depth of 90 cm. These measurements demonstrated extreme spatial variability in nitrate distribution and water movement. Soil transformations of legume and fertilizer N sources were compared using labelled amendments. Early measurements show greater nitrate leaching with legume N due to the mulch effect reducing evaporative water removal.