Estimation of Crop Water Requirement of Soybean and Cotton Crops for Marathwada Region, India

The reference evapotranspiration (ETo) is an important agrometeorological parameter used for various agricultural & meteorological applications. In present study daily reference evapotranspiration (ETo) was determined by Hargreaves method for seven districts of Marathwada region by using long period weather data (29-35 years). The results revealed that, ETo increases continuously from January and reaches to its maximum during May, with quite differences among the districts. The ETo reaches to its peak value during 28th April to 18th May at all the districts. During June ETo decreases sharply and remains low during July, August and with slight increase during September, then it decreases afterwards. The mean water requirement (ETc) for soybean crop during initial stage was found to be lower (2.09 to 2.29 mm day-1) then it increased during developmental stage (3.37 to 3.75 mm day-1) and mid season stage (4.90 to 5.32 mm day-1) again decreased during late-season stage (2.25 to 2.41 mm day-1). The total water requirement of soybean varies between Parbhani (457.81 mm) to Aurangabad (419.60 mm). The mean water requirement of cotton during initial stage (1.77 to 1.95 mm day-1), then after increases at developmental stage (3.42 to 3.78 mm day-1), and mid season stage (5.09 to 5.46 mm day-1) again during late season stage it decreases (1.94 to 2.09 mm day-1). The total water requirement of cotton varies between Parbhani (687.88 mm) and Aurangabad (638.80 mm).