DRAINAGE LYSIMETRY FOR DETERMINING THE CROP COEFFICIENT OF PITAYA CROP BASED ON REFERENCE EVAPOTRANSPIRATION AND CROP EVAPOTRANSPIRATION

Abstract

Determining the amount of water used in agriculture is fundamental for efficient irrigation management. There are different methods for determining a crop's water needs, either directly or indirectly. The objective of this work was to determine the ETc of Pitaya (Hylocereus spp.) using drainage lysimeters, calculate the ETo using the mathematical models of Penman-Monteith (hourly and daily), Hargreaves and Samani, Jensen-Haise, Makking, Blaney-Criddle, and Priestley-Taylor, and determine the Kc for the crop. The experiment was conducted in an experimental area on the Agricultural and Biodiversity Sciences Campus (CCAB) of the Federal University of Cariri (UFCA), Crato – Ceará, and the data for calculating ETo were obtained from the meteorological station located on the campus itself. The Kc of the crop was calculated using the ratio between ETc and ETo. Drainage lysimeters allowed for the estimation of crop ETc for the study period, totaling 204.3 mm. The hourly summation ETo method overestimated the standard daily method, and the alternative method that most closely approximated the standard method was Blaney-Criddle. The average Kc value obtained using the standard daily FAO method was 0.66.