Deterministic and Stochastic Evaluation of Nitrate-Nitrogen Leaching from Soilswith Dual Pore Systems in Karst Regions

摘要

The pollution of groundwater by manure, fertilizers and pesticides is increasingin the southeastern Pennsylvania. A large part of the pollutants reach the groundwater via soil macropores, earthworm holes and cracks. Field experiments were conducted to study the movement of water and contained solutes in soil with dual pore systems under saturated conditions. The experiments were conducted on Duffield silt loam and Clarksburg silt loam soils in southeastern Pennsylvania. Infiltration rates and bromide transport were measured. The LEACHP model was used for the 1987 and 1988 growing seasons for the control, two broadcast ammonium nitrate and three manure treatments. Simulated results were compared with results from field experiments measured nitrogen uptake and nitrate storage in the soil profile, as well as mineralization and nitrification rates were higher in 1987 than in 1988. The simulated nitrogen uptake agreed in all cases with measured nitrogen removal by crops. LEACHP model was used to simulate the amount of bromide leached in each infiltrometer. The model predicted an average of 52% leaching below the root zone and a significant correlation (r=0.88) was found between the measured and model predicted results.