Optimize Above–ground Drip Irrigation Systems for Small Areas

Drip irrigation systems offer the potential for efficient irrigation of high value crops and have proven feasible from engineering and agronomic standpoints in the northern Great Plains. However, little information is available in this region regarding the optimum design and economics of these systems. The objective of this study was to develop a computerized model for design and economic optimization of above–ground drip irrigation systems for carrots, cabbage, onions, and sweet corn. The method of complete enumeration was used to find the optimum sizes of main line, sub main, and lateral pipelines using hydraulic principles; field, crop, water, and soils information; and characteristics and costs of drip irrigation components. Economic analyses were performed using 0.4–, 0.8–, 1.6–, and 4.0–ha fields with one, two, or four irrigated zones and two possible well locations. Benefit–cost ratios (B/C ratios) were estimated. The cost per area of a drip irrigation system was highest for the 0.4–ha field with four zones and the water source located at the corner of the field and lowest for 4 ha with four zones and the water source located at the center. The B/C ratio was highest for a 4–ha field with four zones and lowest for a 0.4–ha field with four zones. Among the crops, the B/C ratio was highest for carrots followed by cabbage, sweet corn, and onion. The model provides useful information in the design and optimization of drip irrigation systems for