CROP COEFFICIENT OF MARANDU PALISADE GRASS: AN APPROACH INVOLVING LEAF AREA INDEX AND CANOPY HEIGHT

Abstract

Determining the evapotranspiration rate enhances our understanding of plant water needs, potentially improving irrigation management. This study aimed to investigate the water consumption of the Marandu palisade grass (Urochloa brizantha) cultivar ‘Marandu’, single cropped and intercropped with black oat and ryegrass, by determining the crop coefficient (Kc) and their correlation with canopy height (CH) and leaf area index (LAI). The experiment was carried out at ESALQ/USP from April 2016 to January 2017. Two weighing lysimeters were used for calculated the Crop evapotranspiration (ETc): one with single-cropped Marandu palisade grass throughout the year and the other intercropped with black oat and ryegrass during autumn and winter (from April to September 2016). Estimated Kc, CH, and LAI were measured every 4-day. Regression equations were generated to determine the correlation between Kc and CH and Kc and LAI in each season. Minimum and maximum Kc values for single cultivation in each season were: 0.61 and 0.97 for spring, 0.45 and 1.10 for summer, 0.47 and 0.74 for autumn, and 0.52 and 0.94 for winter.  In the intercropped cultivation, Kc values ranged from 0.62 to 1.04.