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Fields of dreams

Cultivating rice via drip irrigation can save plenty of water, but it has to be commercially viable first.

They call it the Research & Development & Demonstration (RDD) farm. A visit to the 1,250-acre estate in Ilayamuthur, some 70 km south of Coimbatore in Tamil Nadu, reveals an impressive variety of vegetation - 66,000 mango trees, 37,000 amla (Indian gooseberry) trees and over 10,000 coconut trees. The future of India's food security (for that matter, Asia's as well), though, lies at an extreme corner of the farm in an area measuring just about an acre. Here is where Jain Irrigation Systems Ltd, the world's second-largest drip irrigation company, has successfully cultivated rice using drip irrigation.

Drip irrigation, which saves water and fertiliser by allowing water to drip slowly to the plants' roots, was invented by Israeli firm Netafim, Jain Irrigation's bigger rival, way back in 1965. Today, the technique is extensively used for cultivating many cash crops. However, rice, the mostconsumed grain on the planet, continues to be grown in flooded fields. That is because paddy is a water guzzler. It takes 5,000 litres of water to produce one kilogram of rice.

Compare this with other grain crops, such as wheat, which consumes 1,480 litres per kg, maize (1,150 litres) and barley (1,000 litres). In fact, a third of the world's fresh water resources are used to irrigate rice. But a looming water crisis across the world and, more so, in developing countries, is forcing researchers to find ways to reduce water usage when cultivating paddy.

According to experts, agriculture is the largest consumer of water, using up to 72 per cent of available fresh water worldwide. Consumption in developing countries is even higher, at 87 per cent. But this share is expected to decline to 62 per cent globally and 73 per cent in developing countries due to higher water demand for urban and industrial use.

This has the makings of a major food crisis. For instance, India has 43.4 million hectares of land under rice cultivation and the output in 2009-10 was 89.31 million tonnes. Any limits on water availability will hurt production at a time when it is estimated that India will need 533 million tonnes of rice to feed its people by 2030. One estimate has it, that by 2025, 15-20 million hectares of irrigated rice globally will suffer some degree of water scarcity.

That explains why efforts are underway all over the globe to reduce usage of water in rice cultivation. "Our challenge has been to develop a novel system that is socially acceptable, economically viable and environmentally sustainable - something that will allow rice production to be maintained or increased in the face of declining water availability," says Bas Bouman, Senior Water Scientist and Head of the Crop and Environmental Sciences Division, International Rice Research Institute, Manila.

IRRI, a nonprofit agricultural research centre, has been doing its bit to save water via technologies like alternate wetting and drying (AWD, also known as controlled irrigation) and "aerobic" rice, where the soil is not puddled or flooded (hence, making the soil aerobic, or in direct presence of oxygen). Bouman adds that even a 10 per cent reduction in water used to irrigate rice would free up 150,000 million cubic metres. That's about a fourth of the total fresh water used globally for non-agricultural purposes a year.

Efforts to reduce water consumption, however, have invariably led to a fall in yield vis--vis flood irrigation - be it the AWD method, saturated soil culture, raised bed cultivation, aerobic rice or using sprinkler systems - as rice is very sensitive to water stress. "Tackling the trade-off between land productivity and water productivity is the key," explains Bouman.

Jain Irrigation's experiment at Ilayamuthur seems to have achieved exactly that. "Our experiment successfully established that rice can indeed be grown under drip irrigation without any compromise in yield compared to flood irrigation and with substantial savings in water and power consumption," says P. Soman, Jain's Senior Vice President of Projects.

The yield from the drip-irrigated field at Jain Irrigation's RDD farm was 3.8 tonnes per acre, compared to 3.1 tonnes per acre output in a nearby conventional flood-irrigated field. "Also, the drip-irrigated field, spread over 27 cents (less than a third of an acre) consumed only 36.4 lakh litres of water during the crop period of three months, against 108 lakh litres consumed by a similar-sized field under flood irrigation - a saving of over 66 per cent. That apart, electricity consumption halved. At the drip-irrigated field, the electricity consumed was 226 units during the crop period. The experiment also proved that weed growth, in the non-flood method, can be successfully tackled by measures such as mulching, that is, laying a bed of either rice husk or a polythene sheet to prevent weed growth.

Exploring Viability
The Tamil Nadu Agricultural University (TNAU) is another institution that's taking a close look at dripirrigated rice. "The basic challenge has been to irrigate the rice fields in a precise manner. Advancements in science have enabled us to release the exact amount of water. We have been growing drip-irrigated rice for three seasons now and plan to take it to multiple locations soon. It will not be too long before drip irrigation of rice can be commercialised," says S. Chellamuthu, Director, Water Technology Centre, TNAU. But challenges remain. To start with, the commercial viability of drip irrigated rice has to be proven.

If the outcome of the Jain Irrigation experiment is extrapolated in terms of revenues, a farmer will earn less (Rs 6,600 per acre) in drip irrigation than through the conventional method (Rs 8,300 per acre). That apart, he will have to make a one-time investment of Rs 57,000 an acre to set up the drip irrigation system, which typically will last for 10 crops. Also, with most states supplying water and electricity free to the farmers, the motivation for them to move to drip irrigation is unlikely to be high without a massive subsidy.

There is also the issue of right varieties. "As rice has always meant flooded rice, not much research has gone into developing rice varieties that grow well under non-flooded conditions. We are now working on them and are confident that we will soon come out with a variety that will offer the same yield as the flooded rice variety," says K. Mohanasundaram, Professor and Head, Department of Rice, TNAU. Jain Irrigation, on its part, will continue its research for another two years. "We want to fine tune the process and look at further savings in cost, especially in fertiliser and pesticide use through fertigation (application of fertiliser through an irrigation system)," says Soman.

He is confident of commercialising drip irrigation in rice cultivation. "Even if 10 per cent of the total paddy area of the 43.4 million hectares, especially areas that are rainfed, are brought under drip irrigation, rice output can increase to 130 million tonnes by 2020," adds Soman. If that happens, that will go some way in adding muscle to the fight against hunger - as well as in freeing up more fresh water for drinking and sanitation.


  • Environmentally Sustainable Even a 10 per cent reduction in water used to irrigate rice would free up 150,000 million cubic metres of water - or 25 per cent of the total fresh water that is used globally for non-agricultural purposes, according to an IRRI estimate Less Power-intensive
  • Electricity consumption at Jain Irrigation's drip-irrigated fi eld was half that of a fl ood-irrigated fi eld Higher Yields
  • Yield at the Jain Irrigation farm was 3.8 tonnes per acre, compared to 3.1 tonnes per acre in a flood-irrigated field