Zero tillage comes of age on the Indo-Gangetic Plains

Agricultural technologies that are simple and appropriate often have the most impact. A concerted effort to promote sustainable farming practices on the Indo-Gangetic Plains is proving this point, where farmers have been quick to recognise the benefits of techniques such as zero tillage, unknown to them just a few years ago. In the winter wheat-planting season of 2004, farmers used this method on 2 million ha across the region.

"It's spreading much faster than projected," says Raj Gupta, regional facilitator of the Rice-Wheat Consortium, a partnership that joins the national agricultural research systems of Bangladesh, India, Nepal and Pakistan with several international agricultural research centres and advanced research institutes.

Zero tillage - which foregoes ploughing between crops - is not a new technology. It is widely used, for example, by large-scale farmers in South America who appreciate the benefits of reduced costs for labour and fuel and - importantly - better water retention by the soil. Consortium researchers hoped the technology would prove transferable to small-scale farming in South Asia.

Residue is the key

Farmers saw immediate benefits in terms of input savings but at first some were reluctant to give up their ploughs, according to Ken Sayre, head of crop management at the International Maize and Wheat Improvement Centre (CIMMYT). "It goes against accepted wisdom, which is that the more you till the better crop you will get," says Sayre. "Also, fields look untidy with no tilling, but the residue left on the surface is in fact key to the success."

A long-term experiment at CIMMYT's headquarters in Mexico provides proof of that. Now in its 14th year, a no-till plot with residue left on the surface sits alongside a control plot from which residue has been meticulously removed. Maize plants that are dark green and healthy tower over the pale, drought-stressed control plants. The residue has protected the soil, reducing erosion and compaction and so allowing water to soak into the soil rather than run away. On the Indo-Gangetic Plains, farmers may not have seen such a clear demonstration, but those who tried out the new method soon saw the benefits, and others followed suit.

Zero-tillage farming requires special planters, and after CIMMYT and the UK's Department for International Development (DFID) provided the first 20 machines, entrepreneurs - some of whom were previously making ploughs - quickly seized the new business opportunity. There are now more than 120 small-scale manufacturers of zero-tillage planters in the region and more than 20,000 planters in use.

Rising to the drought challenge

Last year was a testing time for farmers on the Indo-Gangetic Plains, as the weather was particularly harsh. Between June and September 2004 the northwestern part of the region suffered drought, while in the east, parts of Bangladesh, Nepal and India suffered their worst floods for two decades. According to Gupta, such unpredictable weather is exactly why resource-conserving technologies are so important in this region. Rice is particularly vulnerable to drought, but where water-conserving technologies were used rice crops were far more resilient, and the rice shortfall was just 3 per cent in the eastern plains .

"Crops survived longer on drought-affected fields where zero tillage or minimal tillage was used and crop residue was left on the surface," says Gupta. "The residue also acts as good weed control."

Other winning technologies were direct dry-seeding and raised-bed planting of rice, judicious use of herbicides, and 'brown manuring' with sesbania. Some farmers took technologies that had been developed for wheat and adapted them for use with rice. Their success will, Gupta predicts, encourage many others to begin using these technologies.

Others decided to diversify their crops. An extra-short-duration pigeon pea, variety ICPL 88039, was particularly successful, with good yields that far outstripped traditional varieties.

The consortium has shown that relatively simple resource-conserving technologies can have major impacts on people's lives. Millions have already benefited. The success of this work was recently recognised by the Consultative Group on International Agricultural Research (CGIAR) when it awarded the consortium its 2004 King Baudouin prize.