Evaluation of Crop Coefficient for Cotton under Akola Region

Abstract

The study has been undertaken to determine crop coefficient for cotton. Climatic parameters (Maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity, bright sunshine hours, wind speed and rainfall), during the growing period of cotton crop (kharif) were collected from agricultural metrological observatory of Dr. PDKV,Akola. Reference evapotranspiration (ET₀ ) was determined by using FAO 56 Penman montheith method. Soil moisture storage was then determined using Thornthwaite and Mather equation. From soil moisture storage, change in soil moisture storage was calculated. The change in soil moisture was compared with actual evapotranspiration measured in the field with the help of lysimeter. The crop coefficients were determined by comparing change in soil moisture storage with the actual evapotranspiration. The maximum Kc value is observed during the initial stage which gradually increases till full growth of the cotton crop and then afterwards it gradually decrease. The Kc values for cotton on daily basis varies from 0.01 to 1.78 similarly on weekly basis the lowest Kc value was found during 26^th SMW and highest Kc value was observed during 40^th SMW. Crop coefficients during various growth stages of cotton crop was minimum 0.25 for square formation to flowering stage and maximum 0.77 for boll setting to ball bursting and boll bursting to first picking stage.