Development of Oil Palm Water Balance Tool for Predicting Water Content Distribution in Root Zone

Abstract

The water content distribution in root zone of oil palm crop is substantial for predicted the crop water usage both for productivity and environmental issues. The varying condition of climate, soil properties, crop stage, ground water existing of oil palm cultivation require the specific water balance analysis model which can evidence the precision condition of water content in root zone. The oil palm water balance tool was developed by inputting the data base including climate, soil properties, crop stage, root density and root zone layer as well. The data was generated through the reference vapotranspiration process by Penman Monteith equation, set parameter of van – genuchten and water flow analysis by Richard equation to bring about the output data in hourly time step which consisted of ETo, soil moisture, cumulative drainage flux, cumulative capillary flux and cumulative water content - rainfall in three root zone. The first, second and third root zone were determined variously depend on the type of soil and the crop stage. The model was built based on the data observation on field research conducted in 3 different condition; the type of soil inceptisol free drainage (without capillary), spodosol with no flux bottom and ultisol with groundwater contribution.