Sensitivity of simulated field water balance to different soil hydraulic data
1996
Asare, D.K. | Sammis, T.W. | Smeal, D. | Jones, T.L.
Knowledge of a model's response to soil hydraulic data generated by different methods can be used in selecting appropriate model soil hydraulic parameters. Four different sets of soil hydraulic data, comprising the air entry potential, exponential parameter for the Campbell's soil moisture release curve model (b-value), and saturated hydraulic conductivity values, were measured directly and predicted using soil particle size fractions and one known pair of soil moisture content and matric potential values. The parameters were used in executing the model LEACHW to approximate cornfield water balance under irrigated conditions. The predicted cumulative corn evapotranspiration and soil profile water storage values were compared with measured data to assess LEACHW's response to different sets of soil hydraulic data and to select appropriate soil hydraulic data for LEACHW simulations. LEACHW predictions were sensitive to the soil hydraulic data used as model input. Sensitivity analysis showed that the exponential parameter for the Campbell's soil moisture release curve model is the most critical model soil hydraulic parameter. Additionally, LEACHW predictions underestimated the measured soil profile moisture content and cumulative corn evapotranspiration regardless of the soil hydraulic data used to execute the model. However, reasonable simulation results were obtained when measured soil hydraulic data were used as input for the model.
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