Water Requirement of Different Crops for Khurda District of Odisha, India

Water is a precious material for living being, so proper utilization is necessary for better crop growth with optimum water use. So water requirement is essential for irrigation. Water requirement of different crops like cereals and pulses is calculated by considering the data available at Bhubaneswar climatic station and DSS_ET version 4.1 software. 30 years long term daily mean climatic data of minimum and maximum air temperature,mean relative humidity, average wind speed, solar radiation, and rainfall were obtained from the OUAT observatory and from the website http://global weather.tamu.edu/home/view/13292. The latitude of the study area is from 18º46’ to 20⁰ 95’ N and longitude of the area is 83⁰ 48^’ to 87⁰ 46^’ E and elevation is 42m. Mean annual rainfall is 1408.4mm and geographical area of the district is 2,89,000 ha. The DSS _ET developed for ET0 estimation includes a model base with decision-making capabilities, a graphical user interface and a database management system. The model base consists of twenty two most commonly used and internationally accepted ET0 estimation methods based on combination theory, radiation, temperature and pan evaporation along with an algorithm based decision-making model. In this study, we try to determine the water requirement of six major crops of Khurda district. Thirteen well established methods are used to estimate the daily reference evapotranspiration for 30 year period. For each crop, reference evapotranspiration was determined by taking 30 years daily average of ET0 for the crop period. Daily crop water requirement was then calculated by multiplying crop coefficient (Kc), value to the estimated ET0 from FAO 56, PM method. Crop water requirement was estimated for each crop using the result of reference ET0 for the crop period. It was found out that there was sufficient surplus water available during Kharif but in Rabi crop needed irrigation because rainfall was not regular. For Kharif long duration rice crop, water requirement was highest and for Green gram water requirement was lowest. So farmers can decide cropping pattern as per the water requirement and irrigation availability in the district.