Water Conservation

User Behavior

Agriculture, especially irrigation, is globally the largest user of freshwater, consuming about 70 percent of all water withdrawn from rivers, lakes, and groundwater. Efficient water management practices and improved irrigation technologies are crucial in reducing water use in agriculture. Irrigation scheduling involves managing the soil water reservoir in such a way that water is available when crops need it. It is necessary to determine all variables of the water cycle. The easiest method of soil moisture monitoring is to observe the soil appearance at various soil depths within the root zone. Other methods to measure soil moisture content, like tension-meters, determine the suction head a plant needs to abstract water from the soil. Monitoring air temperature, precipitation, air humidity, and evapotranspiration is important to determine how much water is available for the crop and helps to estimate when and how much water should be used during irrigation.

In developed countries, sophisticated digital recording systems are used to control and monitor water availability, as well as water applications. Many types of irrigation systems are available, such as sprinkler, center-pivot, furrow, and flood irrigation systems. However, drip irrigation is the most efficient method as far as water and nutrient applications are concerned, and it can be effectively applied on uneven terrain and in high-value greenhouse crops. With all irrigation systems, drainage of irrigation water is a crucial component of avoiding water pollution. Inefficient irrigation and drainage management, together with inappropriate irrigation, lessens water quality and causes severe soil salinity problems.

In areas where sprinkler systems are used, care should be taken to ensure that the system is not over-designed; furthermore, sprinkler use in hot climates is a cause of increasing soil salinity, since precipitating water droplets evaporate easily, leaving salt crystals behind. Automatic systems should incorporate an override to prevent the sprinklers from operating during wet periods. Plants with similar water needs should be grouped together so that they can be watered for the same length of time and in the same amounts. In cases where expensive irrigation systems are used, they should be equipped with a soil moisture controller that will restrict irrigation to when it is needed.

In small-scale schemes, irrigation should be restricted to the early mornings when evaporation is lowest and crop water demand is highest. Many varieties of grasses used in the lawns of housing areas in developed countries are not drought-resistant and require regular irrigation, though drought-resistant species are available. Small trenches can harvest natural runoff and irrigation water to the areas where needed. Creating micro-basins around specific plants will enable them to be watered individually. Spreading mulch reduces the water lost to evaporation by up to 70 percent, as well as preventing excessive runoff, inhibiting weed growth, and supplying nutrients to the soil. Drip irrigation uses significantly less water than normal irrigation systems and is equally effective. With increasing prices for piped water, the investment for the drip systems may pay off quickly. While small-scale farmers in developing countries often lack resources to invest in pumps or sufficient energy for technical irrigation, low-cost irrigation technologies (such as treadle pumps and drip irrigation) are becoming more widespread.

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