Improving water use efficiency on irrigated dairy farms in Canterbury

Abstract

Water Use Efficiency (WUE) is an important performance indicator of sustainable production, widely used overseas. WUE is defined in a number of ways, and it is important to know what definition is being used. Overseas data show that WUE on dairy farms depends on both the efficiency of applying water to the paddock, and the efficiency of feed utilisation off the paddock. Pasture WUE requires measurements of the amount of water applied and the amount of pasture produced, which are rarely concurrently measured on dairy farms. Estimates of pasture WUE from previous research experiments are highly variable because of uncertainties about how much water was applied. We have suggested a benchmark for WUE based on measurements on commercial dairy farms, and suggest some ways that farmers can improve their irrigation practices. Keywords: water use efficiency, pasture yield, irrigation, evapotranspiration