Drip Irrigation has its place…

I am reading more these days on the latest technological innovation for water conservation. Specifically, I am looking at the agricultural sector of Canada and California. Agriculture accounts for ~ 70% of Canada’s water supply which means that a vast amount of water withdrawals are from farmers mostly for irrigation purposes. However, water is more abundant in Canada than California and shortages in this populated state have driven technological innovation in the area of water conservation.

In California, irrigation use constitutes a massive share of the water withdrawals from the Delta and San Joaquin River - the Delta and San Joaquin river make up the biggest water distribution system for the state. In fact, it provides drinking water for 25 million people and supports California’s trillion dollar economy and $27 billion agricultural sector. With current water shortages in southern California, the importance of actually conserving water has become an omnipresent reality. Farmers are looking at ways in which they can optimally conserve their water resources to maintain adequate supply. A quick solution: drip irrigation.

The conventional methods of water irrigation include flood and sprinkler irrigation. However, the irrigation efficiency for both methods ranges from ~ 40-65% because some water is lost in this process as runoff occurs through percolation and evaporation because the surfaces or soil cannot drain vast amounts of water at a single time. But generally, flood irrigation is inefficient because a lot of water is used and not all of it is drained or absorbed by the soil but instead runs off into rivers and is lost. By contrast, drip irrigation systems reduce percolation below the root zone and increase soil absorption of water. Water is delivered closer to the soil and plant roots and this reduces evaporation losses that would normally be lost in a flood irrigation process.

It saves ~ 25-95% of water compared with flood irrigation. How does it work? It requires rigid plastic pipes that are laid on the surface or buried below ground in each crop row at the root line. Small holes allow the water to drip from the pipe directly to each plant root system. The amount of water applied is regulated by the hole size in the distribution tubes and the water pressure in the system. For a diagram, see here.

Places with large agricultural sectors like Israel and California have started using this technology. Tomato farmers in the famous San Joaquin Valley of California have installed drip irrigation systems. Farmers found that yields increased 5.4 tonnes per acre to 10.1 tonnes per acre using drip irrigation technology. Sure it is expensive, but any novel water conservation technology these days ain’t cheap. This is why state governments in the US are allocating more funding and providing subsidies to farmers who use this technology. In sum, drip irrigation allows you to use less water for your crops and plants but allows you to increase your yields because every drop of water is being used and very little is lost.

Key Message: Water conservation requires all stakeholders to be involved. The agricultural sector is an indispensable player and recent initiatives like drip irrigation need to be actively pursued. Conserving water is economically advantageous but requires some initial investment to get the ball rolling.