Abstract:

Irrigation is the supply of water to crops by artificial means. It is designed to permit the desired plant growth in arid regions and to offset drought in semiarid regions or subhumid regions. Even in areas where average seasonal precipitation may seem ample, rains are frequently unevenly distributed, or soils have low water holding capacities so that traditional rain-fed agriculture is a high-risk enterprise. Irrigation provides a means for stable food production. In some areas, irrigation prolongs the effective growing season. With the security provided by irrigation, additional inputs like higher producing varieties, additional fertilizer, better pest control, and improved tillage, become economically feasible. Irrigation reduces the risk of these expensive inputs being wasted by drought. As the worldwide population continues to grow, irrigated agriculture will be an increasingly important contributor to meet the worldwide demands for food, fiber, animal feed and biofuels. In the United States, irrigated farmlands comprise just 17 percent of crop acres, which contributes about half the value of total crops sales. However, irrigated farmland is credited with the largest share of the national consumptive use. While striving to meet the growing demand for more crops, the competing demands on the available water supply for human well-being and protecting the environment have to be resolved. Efficient irrigation is an integral part of meeting these future challenges.