Economics of Sprinkler Irrigation Systems

Abstract

ABSTRACT ANNUALIZED profit is optimized for a hand move aluminum sprinkler irrigation system using sprinkler spacing, applied water, and characteristic pressure as independent variables under no wind conditions. Income is calculated using a cotton water production function, and expenses include water, energy, pipe, sprinkler, and pumping plant costs. The algorithm accounts for variation in pressure throughout the water delivery system and in averaged local yield for a level field. Profit is relatively insensitive to pressure, but optimum spacing changes with pressure to maintain profitability for the sprinkler tested. Optimum values of applied water is 5 to 15 cm below peak yield depths. Profit is not significantly different for high and low pressure nozzles and is highly sensitive to cotton price, but relatively insensitive to water and electricity costs, lateral diameters, and interest rates. Implications for retrofitting existing systems with low pressure nozzles are discussed and rules of thumb for design and operation based on sprinkler wetted diameters suggested.