Development of crop coefficient models of castor and maize crops

•Crop coefficient polynomial models were developed for castor and maize crops.•Performances of the models were tested using performance indicators.•The models performed well for both the crops.•The models can be used for estimating crop coefficients for any day after sowing.

Castor and maize are the most commonly cultivated crops in the Rajendranagar region of Andhra Pradesh, India. The study aims to develop a crop coefficient (Kc) models for these crops, using Lysimeter measured daily crop evapotranspiration (ETc) data and daily reference evapotranspiration (ET0) computed using FAO-56 Penman-Monteith (PM) method. Kc values obtained using relationship Kc = ETc/ET0, crop coefficient curves were derived as a function of days after sowing and polynomial model was fitted. The performances of the models were tested using performance indicators. The models performed well for both the crops. These models can, therefore, be used for estimating Kc values of castor and maize crops for any day after sowing in the study region.