Premium
A usable mechanistic model of nitrate leaching II. Application
Author(s) -
BARRACLOUGH D.
Publication year - 1989
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1989.tb01296.x
Subject(s) - leaching (pedology) , nitrate , subsoil , lessivage , soil science , environmental science , soil water , water flow , leaching model , hydrology (agriculture) , chemistry , geology , geotechnical engineering , organic chemistry , soil salinity
SUMMARY Simulations produced by a mechanistic model are compared with field observations of nitrate leaching from 0.35 ha hydrologically isolated experimental plots. The parameters used in the model are obtained in two ways. First by fitting the model to field observations in one year. These parameters are then used to simulate leaching in other years. Second, model parameters are obtained by fitting eluant profiles from pulse inputs of solute to undisturbed cores in the laboratory. When used with the field‐derived parameters, the model simulates total leaching losses well in other years, although the pattern of loss is only approximately reproduced. The simulation suggests that water and solute flow in drained, structured soils is complex; preferential flow in the upper horizons resulting in 20% of the water‐filled pore space carrying most of the solute flow, and by‐pass flow in the subsoil causing rapid movement of water and solute to the drains. The result is that much of the nitrate in the upper horizons appears to be protected from leaching. When used with laboratory‐derived parameters, the model was a poor predictor of both the pattern and quantity of nitrate leached.