COMPARISON BETWEEN SIMULATED AND MEASURED PROFILE WATER DISTRIBUTION

Physically based mathematical models are capable of portraying the pro cess of soil water utilization by crop roots. However, there are few d etailed studies comparing simulated profile water content with those o bserved experimentally in varying soil moisture status. The purpose of the present study was to test the accuracy of a diffusion based soil water simulation model under wet, moderately wet and dry soil water re gimes in a coarse textured lateritic (Oxic Haplustalf) soil using pean ut as a test crop. Simulated water content (SWC) usually matched well with the measured water content (MWC), the matching being very accurat e when roots penetrated to the maximum depth (1.2 m). During the early part of the drying cycle simulated values were closer to observed val ues than they during the middle and later part of the drying cycle. Un der wet regime simulated values were closer to observed values.