Abstract
The purpose of this study was to apply water flow equations by using mathematical model in one and two dimensions equations by finite element, and compare the results with the fieldcondition. The study was conducted at the farm of College of Agriculture and Forestury/ Hammam Al-Alil from 1-11-1997-1-6-1998. including the following experiments:
1-Evapo-tranbspiration and moisture redistribution :Field experiment were conducted with two treatments,the first one was planting and planting,the second one was irrigated and non-irrigated (depending on the rain only).2-Infiltration:A double ring infiltrometer with inside diameter 20 cm and a hight of 30cm was used to measure average and accumulated infiltration,and also the vertical moisture distribution. 3- Two dimentional moisture distribution: A double ring infiltrometer was used ,water was supplied continuously for six day,soil moisture content was measured at depths 5,10,20,100,cm with intervals of 6,12,24,72,96,120,144 hours on the radius of circle which has the ring in its center. Computer program was developed with Fortran language to solve Richard's equation using finite element in two dimensions. This program includes a main program that controls other program subroutines. Generally the results show a good agreement between the measured and calculated data for all the conducted experiments which can be summarized as follow:1- High agreement was found between the measured and calculated volumetric moisture content for non irrigated and planted treatment. The percentage of the average deviation not exceed 5% for all measured soil depths and intervals. While the percentage of the average deviation around 11% for irrigated and planted treatment. Lower agreement was found for non-planted treatment at the end of the experiment especially with depths less than 20cm and more than 70cm. 2- Good agreement was found between measured and calculated accumulated and infiltration rate and the percentage of the average deviation of 9% and 15% respectively. On the hand, highly agreement was found between the calculated vertical moisture distribution and measured one except the moisture content at the interface between the two layers. Comparing the measured volumetric content in two dimensions with the calculated one, the percentage of average deviation does not exceed 5% for all the experiment time of 5 days value. 3- T he model sensitivity of unsaturated hydraulic conductivity was greater in case of reducing the value of hydraulic conductivity than increasing its value.
