Alternative Water Sources - Dry Farming Principles and Practices, Crop Production | Crop Production Notes- Agricultural Engineering PDF Download

Further efficiency gains at the local or regional levels, and even at the farm level, can be achieved through the use of alternative sources of water for irrigation. Two major approaches dominate. 

Rainwater harvesting is an increasingly popular approach in those parts of the world where short periods of heavy precipitation are often followed by long stretches of dry periods. In these locations, impermeable surfaces covering sufficiently large areas are created to reduce the infiltration of rainfall into the soil. By controlling the run-off of the harvested rain, water is diverted to tanks, underground aquifers, or dedicated surface ponds (though this is the least costly alternative, it results in excessive water loss via evaporation), from where water can be extracted and used for irrigation. Rainwater harvesting is successfully used in parts of India cohabited by multiple small-scale farmers. 

Utilizing treated wastewater is another approach that can provide a feasible alternative source for irrigation water. With the use of modern technology, domestic wastewater can be treated to meet strict health and environmental guidelines, allowing safe use in irrigation. Conventionally, however, use of treated wastewater in irrigation practices has only been possible in farms located in close proximity to cities or towns that are large enough to operate an effective wastewater treatment system. Treated wastewater is already used in irrigation in Jordan and Tunisia and in landscaping in member countries of the Gulf Cooperation Council. With advancements in wastewater treatment technologies, use of treated wastewater on a smaller scale and in a distributed mode is becoming feasible.

Other innovations, such as micro-scale solar desalination units that can convert brackish water to low salinity water suitable for irrigation, are developments that hold a promise for the future.