Simulation of linear and non-linear soil water deficit due to tree water uptake

Abstract

The simulation of water uptake model is extremely important to anticipate the moisture content changes in the soil. It is very helpful to the development of geotechnical foundation and geo-environmental problem. There are some water uptake models have been developed by other researchers. However it is lack of software programme to plot and analyse the model. Hence, this project focuses into the development of coding for linear and non-linear water uptake model. Prasad linear model and Li et al. exponential model was simulated by using Visual Basic 6.0. The result was verified and showed a good match with the model. The exponential model also compared with CERES model. The sensitivity of linear and exponential model was investigated and also the comparison between both simulated models. The results show that the total water extraction of linear model does not affected by rooting depth but very sensitive to potential transpiration. For exponential model, the increment of total water extraction is constant with the same increment of potential transpiration. Total water extraction of linear model is lower compare to exponential model. Besides, the extinction coefficient, b shows the least effect to the total water extraction. This value of 0.15/cm and higher shows that the rate of extraction is almost zero when deeper than or equal to 60% of rooting depth.