Determination of Crop Water Requirement and Irrigation Scheduling for Banana

Over the last century, the global population has tripled, and water consumption has increased threefold. Water use in India is no exception to this general trend. The main cause of the increase are growing population and rising food demand. In an agrarian economy like India, the importance of water for agricultural productivity hardly needs any emphasis. With increasing scarcity and growing competition for water, judicious use of water in agricultural sector will be necessary. This means that exact or correct amount and correct timing of application should be adopted. In addition, it will need more widespread adoption of deficit irrigation, especially in arid and semiarid regions. Recent advances in new irrigation technologies will help to identify irrigation scheduling strategies that minimize water demand with minimal impacts on yields and yield quality, leading to improved food security. Irrigation in India includes a network of major and minor canals from Indian rivers; groundwater well based systems, tanks, and other rainwater harvesting projects for agricultural activities. The estimation of "Crop Water Requirement" is essential for irrigation planning and management. The increasing demand and scarcity of water makes it important to use the available water in the most economic way. The accurate determination of an irrigation schedule is a time-consuming and complicated process. The introduction of computer programs, however, has made it easier and it is possible to schedule the irrigation water supply exactly according to the water needs of the crops. Ideally, at the beginning of the growing season, the amount of water given per irrigation application, also called the net irrigation depth, is small and given frequently. This is due to the low evapotranspiration of the young plants and their shallow root depth. During the mid-season, the irrigation depth should be larger and given less frequently due to high evapotranspiration and maximum root depth. Thus, ideally, the irrigation depth and/or the irrigation interval (or frequency) vary with the crop development."Irrigation Scheduling" is necessary to improve the overall efficiency of irrigation projects. Correct assessment of crop water requirement under superior condition is an essential element in order to determine the amount of water required and time of irrigation. The objective of this study is to estimate the crop water requirement and irrigation scheduling using "CROPWAT" for Banana. The CROPWAT is based on penman-monteith method. The study area is Dhandhoda station of Vadodara district in Gujarat, India. Various soil data, i.e. type of soil, infiltration rate, water holding capacity are determined by field experimentation. Climatological data of ten years (2005 to 2014) are used for this study. Irrigation scheduling is carried out for various scenarios as Irrigation at critical depletion, Irrigation at fixed depletion (40 mm) , Irrigation at fixed intervals per stage (7 to 10 days) , Irrigation at user defined intervals (40/50/60/70/80/90/100 days). The study reveals that out of four scenarios studied, the critical depletion scenario is the best one as the yield reduction is minimum. Crop water requirement for Banana varies from 936.6 mm to 745.6 mm over a period of ten years. Crop water requirement of Banana crop for the year 2014 is 853.8 mm and as per irrigation scheduling carried out by Critical depletion scenario, the total depth of irrigation is 878.8 mm with 0.1 percent yield reduction. It is recommended to irrigate the field as per critical depletion scenario as it applies water before the crop goes under water stress and hence it gives maximum yield.