Wetenschap - 31 oktober 2002

Alterra-ILRI helps Indian farmers deal with salinity problems

Alterra-ILRI helps Indian farmers deal with salinity problems

The fight against 'white gold'

Waterlogging and salinity of agricultural land is a big problem in India. It affects millions of hectares of land, leading to decreases in yields of rice and other crops. Farmers in a number of states are managing to turn the tide, with sophisticated drainage systems and by making more efficient use of the water available. They have been assisted in their efforts by research and advice from Alterra-ILRI (International Institute for Land Reclamation and Improvement) and a number of Indian agricultural universities.

The owners of salt companies in the coastal areas of India speak of the 'white gold', but for most farmers in the subcontinent salt is a problem they can do without. An estimated eight million hectares of land is affected by salinity problems, which has led to a sharp decrease in crop production. A halving of yields is not unusual. One of the causes of increased salinity is too much irrigation using river water. This practice leads to a rise in the ground water level, and this in turn causes salts to accumulate in the upper layers of soil. The salt dissolved in river water cannot drain away because of the high ground water level.

"The problem is that where there is irrigation, Indian farmers use too much water," explains Dr Hans Boonstra, India expert at ILRI, which just recently joined Alterra. "This messes up their soils and opens the way for very bad harvests in the future." A large number of farmers have ample water available thanks to a number of very large projects completed in recent decades. These include a number of dams built in rivers such as the Narmada, and the canals also built. Increases in the water supply often lead to wastage of water.

Drainage expertise

Boonstra is chief technical advisor for the Indo-Dutch Network Project (IDNP). The project, which was financed by the Dutch and Indian governments, started in 1995 and came to an end at the beginning of this year. Dutch drainage expertise was used in seven pilot areas in the states of Andhra Pradesh, Karnataka, Gujarat and Rajasthan. "The Dutch drainage expertise is beginning to show its profits. In the pilot areas agricultural production rose by 30 to 40 percent after a few years," says Boonstra. The key to the success was that different drainage systems were used. "The most simple is to dig a canal, but the Indians were not always keen on this, as a canal takes up land that otherwise would be used to grow crops. Underground pipes can also be used, and we have calculated that by using a combination of systems costs are redeemed within three to eight years." Researchers from a number of local agricultural universities worked together with ILRI and the Central Soil Salinity Research Institute to formulate packages of measures for various agricultural areas. For example, whether pumping will be necessary or not depends largely on the relief in a particular area.

New agreement

Wageningen UR has recently started a cooperation agreement with the biggest agricultural university in India, the Acharya N.G. Ranga Agricultural University in Hyderabad. The first project is concerned with further measures to combat waterlogging and salinity, and improved water management in Andhra Pradesh. It is a five year project that will not only involve Alterra, but also a number of other Wageningen UR groups: Plant Research International and the Irrigation and Water Engineering Group.

The Dutch government has put up nine million euros for the project, the Indian government half a million euros and Indian farmers will contribute 100,000 euros. Boonstra is not surprised at the reduction from five states to just one at this stage. "Each state in India is the size of many countries. If you spread the help over the whole of India you would achieve very little. It's better to concentrate on one state."

Bottleneck

Irrigation experts realise that drainage is necessary in the areas where salinity has increased, but argue that it is better to prevent the problem in the first place. Boonstra: "That farmers should not waste so much water is easier said than done. One bottleneck is that farmers in higher areas use too much water, and that the downstream farmers sometimes then receive no water at all. In many cases water distribution need improving." Boonstra also believes it is imperative that farmers be made aware of the unequal distribution of water and of the increasing salinity.

Another solution is to grow salt-tolerant crops instead of building drainage systems, a subject currently being researched by scientists at Plant Research International. Whatever ideas come out of the project, it is essential that they are tested on real farms. Boonstra: "If you just go along and tell farmers what they should do, without giving them concrete evidence, it is unlikely that they will do anything. Drainage and other measures must be tested on farmers' land. A university test field won't do either: then they're likely to say 'it works on a test field, but not on my land'."

The cost of measures is also an important issue. The majority of Indian farmers have little or no financial reserves, or are in debt. Boonstra is aware of the problem: "We look wherever possible for cheap solutions. It is important to know that state governments award agricultural subsidies and that agricultural cooperatives and some banks also offer development loans to farmers. For instance, it is possible for farmers to take out a low-interest loan to purchase fertiliser. We are going to try and get these financial institutions to also finance the technological measures we come up with. The problem we encounter at the moment is that it is only the well-off farmers that drain their land and adopt other measures to combat salinity. The majority of farmers are smallholders and not even capable of doing so."

Hugo Bouter

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