Surinder Sud: Getting a handle on pitcher irrigation

FARM VIEW

The good-old earthen pitcher may no longer be merely the poor man's water cooler. It has found a gainful application in agriculture as a micro-irrigation device in areas where water is scarce or slightly brackish.

The technology for supplying water to plants through pitchers, evolved by Indian farm scientists, not only helps save water but also facilitates good crop yield and better returns to the growers.

Pitcher irrigation is essentially a desi version of the more sophisticated drip irrigation systems that are in vogue in water-scarce countries like Israel. And like drip irrigation, its objective is the same "" application of water directly and only to the root zone of each plant.

This eliminates wastage of water due to evaporation and over-supply even as it meets the plants' water requirement in an optimal manner.

Simply stated, the pitcher irrigation technique involves burying pitchers in soil with their mouths above the surface to facilitate filling of water and planting crop seeds around them.

Water seeps through pitcher walls and keeps the soil of the plant root zone sufficiently moist to support plant growth. Compost and fertilisers can be mixed with the soil around these pitchers.

Though pitchers can also be kept on the land surface around the plants, their effectiveness is highly reduced. There is loss of water due to evaporation from the pitcher surface. There is also a danger of salt accumulation on the pitcher surface, further impairing the efficacy.

However, the success of farming with pitchers depends on the precision with which these pitchers are spaced in the fields, the number of plants to be grown around each of these pitchers, and a host of other agronomic practices in keeping with the requirement of individual crops.

These details have been worked out by the experts of the Karnal-based Central Soil Salinity Research Institute (CSSRI) and are available to farmers as a complete package.

The CSSRI experiments have revealed that this technique can be used in several crops, especially vegetables and horticultural crops. In fact, creeping-type horticultural crops need fewer pitchers.

The institute has managed to harvest about 3.5 kg of grapes and 5.8 kg of tomato from the plants sown around each pitcher.

The yield of creepers such as watermelon, muskmelon and gourds has been even better "" the average for watermelon being around 11.3 kg per pitcher and that for bottle gourd nearly 21.5 kg for every pitcher. Even cucumber yield comes to about 14 kg a pitcher.

The main advantage of the pitcher as a water delivery device is its low cost and local availability. Unglazed pitchers are needed, which are made by local potters all over the country.

If these pitchers have to be bought, the cost works out to be only about Rs 11,000 per hectare for crops that require 2,500 pitchers per hectare.

In comparison, the initial installation cost of other available methods of drip and micro-irrigation is several folds higher and is out of reach of most farmers unless subsidised by the government.

The cost-benefit ratio of pitcher farming has been assessed by CSSRI at around 1:2 in most crops. In tomato, it has been as high as 1:3.

Another other major advantage is the suitability of this technology for using moderately-saline water for irrigation. The total water consumed for growing a crop in its entire season has been estimated to be equivalent to that normally used for two irrigation cycles through conventional methods.

However, there are a few precautions that pitcher farmers need to observe. The soil around pitchers should be in firm contact with them. Otherwise, the water will not flow out of the pitchers, or the flow may be uneven and irregular.

Only clear water that is free of mud and sediments should be used. The mouth of the pitchers should be covered to keep it away from sunlight, which normally results in algae in water, thus stunting plant growth.

With water rapidly becoming scarce even in areas where it was abundantly available till recently, it has become imperative to promote ways and means of economising on its use. The quality of available water, too, is deteriorating.

Under these circumstances, technologies such as pitcher irrigation can prove a boon for farmers. The government already has some schemes for subsidising drip irrigation equipment to encourage micro-irrigation. This cheap, simple and easily adaptable irrigation technology, too, can be brought under these schemes.