Techniques of soil moisture measurement for enhancing irrigation water use efficiency

82-86One of the major concerns in irrigated agriculture in India is the poor water use efficiency. The share of irrigation water in the total demand is bound to decrease from the present 84% to 74% due to more pressing and competing demands from other sectors by 2025 AD. As such, the research on improving the present level of water use efficiency in irrigation assumes a great significance in water resource management. In this perspective, soil moisture measurement and its use in irrigation scheduling can play a vital role in increasing the water use efficiency. A tendency to over- or under-irrigate the cropped fields results due to the absence of information about the soil moisture status down the soil profile. Application of precise quantities of irrigation water at the right time not only ensures a high efficiency of water use by the crops, but also reduces nutrient losses through leaching, results in better aeration of the soil, and significantly improves crop yields and farm productivity. Soil moisture readings are useful in determining how much water is available for the crop, when to start irrigation and how much water to apply. Soil moisture monitoring, therefore, helps conserve water and energy, minimize pollution of surface and ground water, and produce optimum crop yields. A variety of methods are available for measuring soil moisture. The selection of method and equipment will depend on ease of use, cost of equipment, applicability to drier conditions, and desire to monitor continuous changes in soil moisture. The present paper aims at disseminating the knowledge of the available techniques and instrumentation for soil moisture measurement and its use in efficient scheduling of irrigation water applications that gives the highest return for the least amount of water