Performance Assessment of Surface and Subsurface Drip Irrigation System for Crops and Fruit Trees

Abstract

The continuous increase in population the water demand by agriculture, domestic and industrial sectors have caused great stress on world water resources. Population in emerging countries is expected to grow; 4.3 billion in 2002, 5.5 billion in 2025 and 6.2 billion in 2050. For the least developed countries these figures will be 0.8, 1.1 and 1.6 respectively. Agriculture sector consumes about 70-72 % of total water resources. Average irrigation efficiency of the world is 37%. The water resources of Pakistan are under immense stress due to increased agricultural expansion, population growth and associated urbanization and industrialization. The gap between water demand and supply is growing rapidly. Based on current population growth rate, the shortage of water in country will increase to 50% in 2025. To overcome this shortage of water, adoption of efficient water saving techniques is the need of day and future food security. The current study was carried out to evaluate the appropriateness of surface and subsurface drip irrigation system for crops and fruit trees. The efficiency of these irrigation systems in relation to yield, yield to water ratio and economic viability of drip irrigation systems under different cropping schemes and varying flexibility drip pipes were also carried out. Three field experiments were conducted, one in greenhouse and two in open field area at Al-Qassim (Buraidah), Saudi Arabia. Under these experiments, surface and subsurface drip irrigation systems were studied in detail in crops and fruit trees. Important parameters of these systems such as hydraulic performance of flexible drip pipes used, water consumption, yield of crop/fruit, yield to water ratio of crop/fruit and cost analysis of surface and subsurface drip irrigation type under crops and fruit trees were determined. The yield under vegetable crop from the subsurface drip irrigation system was found to be 28% and 25% (Notorah and Red rock varieties of tomatoes) more than that from the surface drip irrigation system. The yield under fruit trees from the subsurface drip irrigation system by using three varying flexible drip pipes (Low, medium and high) and was found to be 42% and 49% more than that from medium and high flexible drip pipes, while under surface drip irrigation system, it was found 46% and 51% more from medium and high flexible drip pipes. The water use efficiency of subsurface drip irrigation system is much more than that of surface drips irrigation system in both vegetable crops as well as in fruit tree because all water utilized by plant in case of subsurface drip irrigation but as for surface drip VIirrigation system partly utilized by plant and partly evaporated, Bigger wetted volume of soil in root zone was observed in the case of subsurface drip irrigation while it is smaller wetted volume of soil in case of surface drip irrigation system. Further investigation of subsurface drip irrigation system needs to be undertaken for other crops and fruit trees to confirm the benefits of the use of low flexible drip pipes.