Crop Coefficients: A Literature Review

Abstract

Recently presented climate change scenarios include increasing demand for water, due to both increase in temperature and variations in precipitation pattern. Since crop water requirements are related to climate and irrigation scheduling depends on crop evapotranspiration (ETc), it is crucial to have tools that allow the estimation of ETc in a reliable way. ETc is often calculated as the product of two factors, the reference evapotranspiration (ETo) and crop coefficient (Kc) values that convert ETo to ETc. This paper reviews Kc values, measured in different parts of the world and in different climates, with the aim to offer a practical tool for selecting the most appropriate Kc values for water balance irrigation scheduling, which result in more efficient irrigation. More than 100 scientific papers were studied and summarized in a report, accompanied by an extensive Kc database. The Kc report and database are available in the “Supplemental Data” section of this paper.