Surinder Sud: Salt of the earth

Sub-surface pipes and bio-drainage are helping revive water-logged and saline land

Sub-surface pipes and bio-drainage are helping revive lakhs of acres of water-logged and saline land.

Farmers whose lands in the vast tracts of canal-irrigated areas have become unfit for crop cultivation due to water-logging and the resulting soil salinity need not despair. Modern technologies are now available to tackle these problems and bring such lands back to productive use.

The problem arises chiefly because of the introduction of canal irrigation without making appropriate provision for drainage of excess water which seeps into the surrounding areas from unlined canals and the over-use of irrigation water. As a result, the water table is rising by 30 to 50 cm per year in most canal command areas. This brings harmful salts present in the deeper soil layers to the upper section of the soil (which constitutes the root zone of crop plants), making it difficult for the plants to survive. The groundwater in such areas also tends to get saline, becoming unsuitable for irrigation.

 

Realising the gravity of this, the Karnal-based Central soil Salinity Research Institute (CSSRI) has developed — and successfully demonstrated in the fields — several techniques to restore the waterlogged and saline lands to farming by drawing out unwanted water and growing those crops which can withstand saline conditions. “Such remedial technologies have already been deployed to reclaim about 1.5 million hectares of land which are now producing nearly 10 million tonnes of rice and wheat annually, besides generating about 175 million man days of employment”, points out CSSRI Director Gurbachan Singh.

One such means to nurse waterlogged saline soils to good health, conceived by CSSRI, is sub-surface drainage which helps remove both excess water and injurious salts. It involves laying out a network of pipes about 1.5 metres below the soil surface to capture surplus water which is then pumped out and suitably disposed of. This technique has worked well in several states, including Haryana, Punjab, Rajasthan, Gujarat, Maharashtra, Karnataka, Madhya Pradesh, Kerala, Assam and Andhra Pradesh. Though the initial investment is high, the returns are large enough to make it economically viable. Its cost-benefit ratio has been estimated by CSSRI at a healthy 1.36.

Bio-drainage is an alternative approach to achieve the same objective of removing accumulated water and salts. It involves planting high water-consuming trees, such as eucalyptus, in waterlogged lands. These trees take up water from the soil through their roots and release it in the atmosphere through their leaves. As such, they virtually serve as bio-pumps.

This technique has proved useful in several canal command areas, including that of the Indira Gandhi canal (commonly called Rajasthan canal). Encouraged by its success, the Haryana government has now planned to take up a massive bio-drainage (tree planting) programme in the waterlogged and saline tracts of Rohtak, Sonipat, Jind, Hissar and Sirsa districts. The Punjab government has also begun a land reclamation programme in the Malout area based on this approach.

Multi-enterprise agriculture is another significant concept to get over the handicap imposed by waterlogging and salt accumulation. Tried out advantageously in the Sharda Sahayak Command area in Uttar Pradesh, this approach involves intercepting water seeping through the canals and collecting it in specially dug ponds about 100 metres away from the canal. This water can then be used for growing vegetables, fruits and food and fodder crops. These ponds can also be used for rearing fish to supplement farm income.

Yet another effective way of dealing with this soil disorder is to go in for the cultivation of salt-tolerant varieties of crops like rice, wheat and mustard evolved by CSSRI. For this purpose, the institute has short-listed seven varieties of rice (named CSR-10, CSR-13, CSR-17, CSR-23, CSR-27, CSR-30 and CSR-36), two varieties of wheat (KRL1-4 and KRL19) and three of mustard (CS-52, CS-54 and CS-56).

Apart from this, CSSRI has also identified several high-value medicinal and aromatic crops which can thrive in problematic soils. These include isabgol, dill, mulathi, salvadora and matricaria.

The Indian Council of Agricultural Research (ICAR) has recently mooted an inter-institutional programme for intensifying research and development work on curing waterlogged and salt-inflicted lands in Punjab, Haryana and Delhi, where this problem is turning rather acute.

All farm research organisations of this region are planned to be roped into this effort.

The lessons learnt from this programme will, obviously, come in handy to combat the scourge of waterlogging and soil salinity in other parts of the country as well.

surinder.sud@gmail.com