EVALUATION THE OPERATION OF A DRIP IRRIGATION SYSTEM IN DIFFERENT TYPES OF SOIL

Abstract

Drip Irrigation Method is the best method that has been used in the world among the other irrigation methods because of its good and high uniformity. This method distributes water to the field using a pipe network and transforms it to the plant by emitters. In spite of the advantages of drip irrigation method, the system has many problems, such as the impact of soil type, silt and discharges distribution. To achieve the goals of using a drip irrigation system, it must be designed and operated properly so that rates and location of delivery of water to the root zone is suitable for crop requirements. Generally, the criterion for drip irrigation system operation is based on soil texture. Soil wetting is one of the most important parameters to determine the deep percolation rate and the efficiency of the system. Knowledge of soil wetting pattern and its movement plays a large role in deciding depth and spacing of pipes, design of irrigation scheduling and improving the efficiency of the drip irrigation system. The objective of this study is to develop an approach to operate the drip irrigation system in sandy and clay soils by a computerized method regarding the type of crops, its consumptive use, type of soil, frequency of irrigation and water distribution in the network .The study adopts two approaches as follows: The field work approach and the theoretical approach. In the field work approach, soil analysis of the physical and chemical properties of the soil which affect the soil quality as well as its suitability for growing plants are determined. For the theoretical approach the well known software CROPWAT is used for the calculation of crop water requirements and irrigation requirements depending on soil, climate and crop data. Measurements of the consumptive use, discharge, velocities, wetted soil width, wetted soil depth, frequency of irrigation for the two types of soil with silt content calculated. The designed discharge was found to be higher in clay soil than sand soil because it saves the water for a long time through a small area as it is little porous. Increasing silt rate for each type of soil, cause to increases the amount of irrigation water requirement. As the wetted soil width depends on emitter discharge and soil type, it will be increase with soils in high silty clay compared with the low silt and bigger as compared to sandy soils.