Low-cost microirrigation system supplied by groundwater: An application to pepper and vineyard crops in Spain

Abstract

The PRESUD tool was developed using MATLAB™ to identify the optimum microirrigation system design. The lowest cost was determined by calculating the annual water application cost per unit of irrigated area (CT). This is defined as the cost of one cubic meter of water applied to crops, and is the sum of investment (Ca), maintenance (Cm) and energy (Ce) costs. This tool optimizes the shape of the characteristic and efficiency curves of the pump and the pumping pipe, distribution pipe, and irrigation system pipes diameters with a holistic approach.All subunits are rectangular, with the well pipe in the center. The lateral and manifold pipe parameters are calculated using a stepwise method. The analysis includes the effects of the main factors in irrigation system design: dynamic lift in the aquifer (DL), number of subunits (NS), irrigated area (S) and crop irrigation water requirements (Rg), among others.The tool was applied to the specific conditions in Spain. Results show that CT decreases with an increase in plot size, and costs are high for plots smaller than 3–5ha. This is due to the percentage of total costs that the tube well and electrical line contribute. CT has a positive relationship with DL. In these case studies, diesel fuel electrical generators are recommended for plots <4ha for pepper crops and up to 15ha for grapevine if DL is 40m. These limits vary with different DL values or changes in the cost and length of the electrical line.