A GLEAMS (ver. 2.10) model was calibrated and validated using three years (1990–1992) of field–measured data to simulate tillage effects on nitrate–nitrogen (NO3–N) and herbicide losses with subsurface drain “tile” water beneath a continuous corn production system. The model was calibrated for chisel plow systems using 1991 field data and was validated against field data of two years (1990 and 1992) for chisel plow and three years (1990–1992) for moldboard plow (MB), ridge till (RT), and no–till (NT) systems. The model simulations were made with a single run using data on measured tile flows; nitrate–nitrogen (NO3–N), atrazine, and alachlor losses with tile flows; N–uptake; and other biomass parameters for the period 1 January 1990 [...]
