| heal.abstract |
A simulation study of the soil moisture content under a prairie field, in Gembloux Belgium, by the use of the one-dimensional model SWAP93, was carried out. In order to determine the optimum relationship that S(max) is following, two concepts of maximum water extraction rate were examined. The first one assumed a linear variation of S(max) with depth z and the second assumed a homogeneous distribution of S(max) with depth z. Five statistical criteria were used to compare the quality of simulation results, such as average error (AE), root mean square error (RMSE), root mean square (RMS), modeling efficiency (EF) and coefficient of residual mass (CRM). The differences between the criteria, showed that the assumption of the homogeneous distribution of S(max) throughout the soil profile resulted in a more accurate prediction of soil moisture content. The agreement between measured and simulated water content profiles, throughout the regarded period, was satisfactory for depths >30 cm. The deviation between simulated and experimental values for depth <30 cm could be explained by the influence from the cracks in the soil surface and wormholes that cause water losses and, consequently, underestimation of the experimental values. (C) 2000 Elsevier Science B.V. |
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