Reference crop evapotranspiration of western part of Maharashtra, India

Reference crop evapotranspiration is a basic parameter required in design of irrigation systems. Six reference crop evapotranspiration methods were studied based on their daily performances under the given climatic condition in the Western part of Maharashtra state. The Penman-Monteith equation standardized by Food and Agricultural Organization (FAO56- PM) was used to compare with the Modified Penman, Hargreaves-Samani, Pan Evaporation, Blaney-Criddle and FAO Radiation methods using meteorological data for 33 years (1975–2007). Performance of these methods was evaluated on the basis of the least root mean square error and regression analysis. Radiation method gave higher values followed by modified Penman, Blanney-Criddle, Pan evaporation, Hargraeves-Samani and Penman- Monteith. Of six methods, Modified Penman gave minimum value of root mean square error and higher correlation coefficient under climatic conditions of Ahmednagar district of Maharashtra.