Crop coefficient for coffee as a function of leaf area index

Abstract

This study was conducted in an experimental site at the Federal University of Lavras, Brazil, to estimate the single crop coefficient (Kc) for drip-irrigated coffee (Coffea arabica) and provide a mathematical descrip tion based on leaf area index (LAI). The cultivar used was Catiguá MG-3 planted in May 2007 with a spacing of 2.5 × 0.6 m. The LAI were obtained from the aver age of plant height and canopy diameter with data de rived from bimonthly measurements between 2007 and 2013. Kc values were determined from crop evapo transpiration (ETc) and reference evapotranspiration (ETo). ETc was estimated from the water balance bet ween the periods of successive irrigations in which there was no precipitation, while ETo was obtained us ing the Penman–Monteith equation parameterized by FAO. To describe the relationship between Kc and LAI, linear and nonlinear models were used. The lo gistic model was best for describing the Kc values as a function of LAI. The determined minimum, mean and maximum Kc values were 0.21, 0.57 and 0.80 respec tively.