Crop Water Requirement using Single andDual Crop Coefficient Approach

The determination of crop coefficients and reference crop evapotranspiration are important for estimating irrigation water requirements of any crop in order to have better irrigation scheduling and water management. The purpose of this study is to determine the crop water requirement of cauliflower, using single and dual crop coefficient approach using FAO-56 Penman–Monteith Method. Meteorological data like maximum temperature, minimum temperature, relative humidity, sunshine hours and wind speed for Vadodara region are used to determine Reference crop evapotranspiration. Crop Coefficient (Kc) can be utilized as single Kc which is influenced by moderate effect of evaporation and transpiration together. Dual Kc is expressed by soil evaporation coefficient (Ke) and basal crop coefficient (Kcb), separately. Kc values for all growth stages are determined using both approaches. Micro irrigation systems are used to irrigate the fields. Cauliflower water requirements (ETc) are 256 mm and 237 mm for single and dual crop coefficient approach, respectively during the growing season. The study reveals that maximum differences between ETc of single and dual Kc values were observed at initial stage. The dual crop coefficient approach is more precise and it is best for real time irrigation scheduling, for soil water balance computations, and for research studies where effects of every day variations in soil surface wetness and the resulting impacts on daily ETc and the soil water profile are important. Dual crop coefficient approach is best suited for high frequency irrigation systems like micro irrigation systems. These results can be useful for agricultural planning and efficient management of irrigation for cultivation of cauliflower.