Calibration and validation of FAO: Aqua crop model for wheat in Vindhyan region

Abstract

This study was conducted for the calibration and validation of Aqua crop model (Version 4.0) for winter wheat (AAIW4) in Vindhyan region at Allahabad (Prayagraj) India. The experimental field was laid out in the research farm of Sam Higginbottom Institute of Agriculture Technology and Sciences, Allahabad (Prayagraj) during Rabi 2014-15 and 2015-16 in Randomized Complete Block Design (RCBD) with 4 treatments viz; I1 (7 irrigation at iw/cpe=1.6, cpe = 37.5mm, 420 mm), I2 (5 irrigation, iw/cpe=1.2, cpe=50mm, 300 mm), I3 (3 irrigation, iw/cpe=0.8, cpe=75mm, 180 mm), I4 (2 irrigation, iw/cpe=0.5, cpe=120mm, 120 mm) and with the soil texture properties as Sand, Silt and clay % was 60,14 and 26%. ETo was calculated using Cropwat 8.0, ETcrop estimated for 2014-15 was 264 mm and for 2015-16 it was 238 mm. This model was calibrated using climatic and crop physiological data of 2014-15 whereas; its performance in simulating biomass and grain yield was validated using the data of 2015-16. The model was evaluated using NRMSE (Biomass 7.5 to 16.5, Yield 5.3 to 9.2), RMSE (Biomass 0.5 to 0.9, Yield 0.24 to 0.5), Pe (Biomass 7.2 to 13.7, Yield -3.4 to 5.2) and ME (Biomass 0.96 to 0.99, Yield 0.99 to 1). The correlation coefficient (R2) for Biomass and Yield was obtained as 0.953 and 0.951 respectively.