Realizing a coming water crisis, Indians are focused on micro-irrigation for greater water efficiency in agriculture and sustainability. The S.M. Sehgal Foundation, Indias leading agricultural development NGO, is pushing for irrigation water efficiency, by pushing for micro-irrigation, mulching, laser leveling, and using water soakers to keep soil moist. The use of micro irrigation decreases the use of water 25-85 per cent, besides improving the farm productivity and reducing the labor costs and weeds and diseases of crops.
The use of drip irrigation systems and emitters has reduced the use of irrigation water in China by 27 percent and Australia by 35 percent. To satisfy increasing demand for food, irrigation agriculture must produce more food using less water, adopting effective micro-irrigation systems such as drip, sprinkler, and reactive methods. To contain excessive water losses, we need to implement more efficient systems such as drip, sprinkler and micro-spray types of irrigation. In many cases, drip is most sustainable because of the precision with which the water can be delivered with little loss.
Also, a sustainable irrigation system leads to higher yields of crops, as the water is directed straight where it is needed the most. Water is a scarce resource, so it requires the use of sustainable irrigation practices in order to conserve it. Although there are different agricultural irrigation systems, flood-and-furrow systems are considered to be the least effective because too much water is lost to percolation and evaporation. For a variety of reasons, many farmers cannot fully depend on rain, and have to resort to irrigation to irrigate crops.
What is important is ensuring a supply so farmers in dry regions can keep growing and making money from their crops. Drip irrigation allows farmers to grow crops in hillsides, since when flooding is required, you only have the option to till flat ground. Drip irrigation delivers water to the roots of the crops; it is delivered at a low pressure, via plastic tubes fitted with emitters for regulation of the rate of delivery. Not only does drip irrigation use between 60 and 70 per cent less water — a precious and finite resource on earth today — it reduces greenhouse gas emissions by using fertilizer more precisely, as the fertilizer is mixed into the water prior to irrigation.
Israel may offer a good example: A desert country that used to be plagued by a shortage of water has turned into one that has water surpluses, thanks to its adaptation of micro-irrigation techniques, particularly drip irrigation, which saves nearly three-fourths of water used in irrigation done via open channels. Another practice possible with micro-irrigation to save resources is fertigation, which involves the combined application of water and fertilizer via irrigation. By applying water directly into the root zone, micro-irrigation reduces the losses of water via transport, runoff, deep penetration, and evaporation.
Water loss via conveyance is inevitable with conventional irrigation practices; micro-irrigation, with its conservation-based techniques, has pioneered a higher efficiency in the use of water, of about 75-95%. Effective irrigation, as a metric of sustainable water use, has limitations in agriculture, as it typically drives intensification, which can, in turn, cause problems such as excessive tilling, poor soil health, erosion, excessive use of fertilisers and pesticides, and higher water usage, all of which negate the gains of efficiency.
Adopting all of the approaches mentioned would accomplish the objective of sustainable water use in agriculture, thus increasing the total water use efficiency of irrigation sector by about 75% to 80%. Initiatives should be taken for improving overall water usage efficiency of surface and groundwater systems of agriculture by 30%-65% to 65%-80%.
The use of surface water for irrigation is highly sustainable in the Northern Territory, as well as the northeastern part of Tasmania. Micro-irrigation, especially drip irrigation, can be limited to garden crops including fruits and vegetables, with priority given to arid, semi-arid, and sandy areas with limited water resources, including Potohar Plateau, and the commanding heights of mini- and small-scale dams.