Soil water dynamics in a grassland of the mid country intermediate zone of Sri Lanka

Abstract

Temporal and spatial variability off soil water content (SWC) in a catchment affects surface and sub-surface runoff, modulates evapotramspiratiom and determines the degree of ground water recharge. The present understanding of soil water dynamics in different land uses in Sri Lanka is poor. An experiment was conducted to study the soil water dynamics in a grassland of mid country off Sri Lanka. Rainfall, runoff and SWC were monitored for two years in an experimental plot of 525 m2. SWC was monitored up to decomposing parent material using neutron moisture meter. Bata showed that the temporal variability off SWC at 15 and 30 cm depths was very high. The variability of SWC in depths below 30 cm was low and showed gradual change with time. The SWC in the profile remained below field capacity most of the time, showing the capacity of the profile to absorb rain water. The runoff from the plot was negligible.