In order to understand the status of soil water under perennial woodlands in the water-limited regions

soil moisture were observed using the neutron probe in the soil profile under Caragana microphylla shrubs in the semi-humid region of the Loess Plateau during April to November from 2002 to 2006.A compartment model was used to study the vertical changes of soil water.The results showed that the characters of vertical variations of the moisture in the profiles were described well by the model with the specifically calibrated parameters and the goodness of fit met the statistical requirement

suggesting a great potential applicability of the model to the similar areas.