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 estimatethe single crop coefficient (Kc) for drip-irrigated coffee(Coffea arabica) and provide a mathematical descriptionbased on leaf area index (LAI). The cultivar usedwas Catiguá MG-3 planted in May 2007 with a spacingof 2.5 × 0.6 m. The LAI were obtained from the averageof plant height and canopy diameter with data derivedfrom bimonthly measurements between 2007and 2013. Kc values were determined from crop evapotranspiration(ETc) and reference evapotranspiration(ETo). ETc was estimated from the water balance betweenthe periods of successive irrigations in whichthere was no precipitation, while ETo was obtained usingthe Penman–Monteith equation parameterized by FAO. To describe the relationship between Kc andLAI, linear and nonlinear models were used. The logisticmodel was best for describing the Kc values as afunction of LAI. The determined minimum, mean andmaximum Kc values were 0.21, 0.57 and 0.80 respectively