Groundnut is an important crop of India. Precise estimates of evapotranspiration can be obtained by multiplying crop coefficients to reference evapotranspiration using readily available climatic data. Penman-Monteith equationisadopted worldwide as the most reliable andaccurate method for computing reference evapotranspiration. The Food and Agriculture Organization (FAO) presented crop coefficients for estimation of evapotranspiration of different crops based on Penman-Monteith equation. The crop coefficient curves canbe developed by plotting the ratios of crop evapotranspiration and reference evapotranspiration with respect to time. The crop coefficient curves developed by the FAO method are designated as FAO-56 curve method. The evapotranspiration values of groundnut crop were measured with the help of electronic weighing lysimeter at Anand. The crop coefficient curves were developed for groundnut by FAO-56 curve method and modified FAO-56 curve method. The FAO-56 curve method underestimates groundnut evapotranspiration by 19.85 per cent. Therefore, FAO-56 curve method does not appear to predict groundnut evapotranspiration accurately. The modified FAO-56 curve method underestimates groundnut evapotranspiration only by 8.37 per cent. Therefore, performance of modified FAO-56 curve method was found better than FAO-56 curve method for estimation of groundnut evapotranspiration.
Development of Improved Crop Coefficients for Precise Estimates of Groundnut Evapotranspiration
