A management-oriented simulation model was developed to predict the movement of nitrogen in and below the root zone of agricultural soils. The model is based on the one-dimensional Richards’ equation for saturated-unsaturated water flow, and the classical convection-dispersion equation for solute transport. The computer program accounts for water and nitrogen uptake by plant roots, precipitation, snow melt, evaporation from bare soil, and a variety of nitrogen transformations including mineralization, immobilization, nitrification and denitrification. The model is partially validated by comparison with a series of nitrate leaching experiments using large undisturbed soil monoliths. Deviations between measured and calculated distributions are attributed to, among other things, poor estimates of the unsaturated soil hydraulic properties and the occurrence of preferential flow of water and nitrates through the soil monoliths.
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- Nitrogen Leaching from Agricultural Soils -A Comparison of Measured and Computer-Simulated Results
M. Th. van Genuchten
- Springer Netherlands