Soil water flow dynamics on raised beds in an acid sulphate soil

Soil water flows and soil moisture dynamics from raised bed system with and without sugarcane crops during the period January to October 1997 was studied. Measurements were made on soil water contents and ground water level. Soil samples were taken once-a week from the beds randomly. Meteorological conditions were collected at Can Tho meteorological station. Cumulative precipitation during the investigation period was of l377.6 mm. The SOIL model has been used as a tool to simulate the soil water flows, and the soil moisture dynamics in the soil profile. The comparison was done on soil water contents and ground water level between simulations and measurements by linear regression. Simulation was successful in reproducing the general pattern of water flow dynamics and water redistribution. Simulated results agreed well with measurements (R2- values for linear regressions in a range between 46.7 % to 88 % for soil water contents). Simulated cumulative soil evaporation amounted to 695.8 mm from the system with bare soil, and 412.2 mm from the system with sugarcane crops. Simulated water flows and water redistribution's were governed of soil properties, precipitation and, and evaporation. The capillary flow was dominant during the period from January to April. Infiltration for bare soil exceeded infiltration for sugarcane plots with 77.5 mm and the correspondent total drainage was exceeded with 203 mm during the investigation period. In the raised beds covered with crops reduced infiltration flows and runoff flows