Estimation of water requirement in maize using CROPWAT model

Abstract

CROPWAT V 4.2 (Crop requirement model) developed by Derek Clarke et al. (1998) was used to estimate water requirement and yield reduction due to water stress in maize, as it is one of the simple scientific knowledge based tool. A field experiment was laid out in a randomized block design with 7 treatments viz., drip irrigation at 50, 75 and 100 per cent of pan evaporation throughout the crop period and with permutation and combinations of the above up to tasseling and during subsequent crop period, rabi 2006-07, at Student Farm, College of Agriculture, Rajendranagar, Hyderabad. Crop coefficient curve was constructed and Irrigation Water Requirement (IWR) was estimated. Close scatter of simulated yields, irrigation water requirement and respective measured values around the regression line and 1:1 line explained 95 per cent variation in yield and 98 per cent variation in irrigation water requirement (IWR) by CROPWAT. The estimated RMSE (Root Mean Square Error) for yield was 400 kg ha -1.