Can crop coefficients improve the economics of irrigated crops?

Climate and market conditions together with water policies have a large impact on agricultural water use. Evapotranspiration (ET) accounts for most of the water loss from a well-managed, irrigated crop, and the crop coefficient (Kc) method is widely used to estimate ET. The ET is used in a water balance calculation to estimate changes in soil water content and to accurately determine how much irrigation water to apply. This can lead to combined sustainable water use and high production for crops grown under specific micro-climate conditions. Crop-water production functions, for an industrial tomato cultivar, were developed for three different locations and climates by using measured agrometeorological data for well-watered crop ET (ETc) determination combined with crop yield data. In particular, the authors used an Excel application program "KcMod" to calculate ETc and a modified version of the MAD6 application program to simulate how crop yield is affected by deficit irrigation. Then, the impact of different scenarios on profitability and economic risk were analysed. Analysis of results highlights the utility of crop coefficients methods. In fact, even considering some limitations, such as not including the relation between water applied and tomatoes' quality, this simple approach can improve significantly the economic performance of irrigated crops.