New Internationalist books and publications

World Development Book Case Study: Does SRI Cultivation Really Work?

In 2011 a young Indian farmer living in Bihar, Sumant Kumar, claimed that he had produced 22.4 tonnes of rice from one hectare of land. That yield was a new world record, beating the previous record of 19.4 tonnes a hectare claimed by Professor Yuan LongpingYuan, director-general of China’s national rice research centre. The big increase on the normal yields achieved by farmers in Bihar has a clear potential significance for this Indian state, where nearly half the population of 100 million live below the poverty line and 93% depend on growing rice and potatoes for their existence. If the techniques used to achieve the high yields (System of Rice Intensification or SRI) can be verified and transferred to other parts of the world it would have an obvious potential to make a big contribution to solving the problem of feeding a growing world population. Opinions about the apparent success of relatively simple changes in farming practice to produce much higher yields than traditional methods range from enthusiastic promotion of SRI to deep scepticism of the claimed ‘miracle’ results.

Recent history of SRI

Credit for the development of SRI is usually given to Professor Norman Uphoff director of the International Institute for Food, Agriculture and Development at Cornell University. Uphoff went to Madagascar in 1983 to research sustainable development after being given $15 million by an anonymous donor. He saw farmers who were using SRI techniques increase their rice yields from two to eight tonnes and in 1997 he started to promote SRI in Asia. It is estimated that there are now 4-5 million farmers using SRI worldwide, with governments in China, India, Indonesia, Cambodia, Sri Lanka and Vietnam promoting its use.

How were the high yields achieved?

SRI works by stimulating the root systems of young plants, mostly by using organic manures and increasing biological activity in the soil. We are still counting the ecological cost of the ‘Green Revolution’ in agriculture of the 1970s which increased global food production but relied on improved crop varieties, pesticides and chemical fertilisers. The most attractive feature of SRI is that it does not require extra expensive inputs from the farmer and is a sustainable form of farming. There are three key elements;

  • Seedlings must be transplanted individually when they are less than 15 days old. This corresponds to the start of the fourth phyllochron of growth. A phyllochron is defined as the interval between growth stages of successive leaves on the same young stem and the fourth phyllochron is the start of the growth of the main stem. Early transplanting prevents the plant from being traumatized by being transplanted after the start of the main growth trajectory. Careful transplanting is essential to promote rapid growth. Traditionally, rice seedlings are planted in clumps which do not allow full root development.
  • Correct spacing between the transplanted seeds is very important. The optimum planting pattern is a square – 25cm x 25cm. This allows for proper root growth.
  • The soil must be kept moist and well aerated, as the roots require access to both oxygen and water. Traditional ‘paddy’ rice cultivation of rice causes hypoxic soil conditions and results in a high proportion of the roots degenerating.

Other practices used in SRI agriculture include: frequent weeding, preferably using a rotating hoe that simultaneously aerates the soil; the application of water on a regular basis either by small amounts daily or alternate flooding and drying of fields; and the adding of organic material to the soil. The organic material can be any decomposed biomass, including manure, mulch or rice straw.

The claimed benefits of using SRI include;

  • A greatly increased number of shoots (tillers) and so greater potential for more grain to grow on those shoots.
  • An increase in root growth, which results in more efficient growth and more force being needed to pull up the rice plants – providing more stability in bad weather such as cyclones. This means reduced risk for the farmer.
  • Larger and more numerous individual grains (panicles).
  • Higher grain quality with fewer unfilled grains and better results after milling. It is claimed that buyers are willing to pay higher prices for SRI rice.
  • Less than half the water used to grow SRI paddy rice compared to traditional methods because the fields are not flooded during the entire crop cycle.
  • Fewer pests and disease attacks, meaning farmers can avoid or reduce the money spent on agrochemicals.
  • Fewer seeds needed because of individual planting. This can greatly reduce the cost of buying high-yielding varieties of seeds. It is claimed that there is no need to buy any seeds at all because SRI methods enhance yields for traditional rice plants.
  • The reduced need for chemical fertilizers and other external inputs means production costs are reduced at the same time as yields are increased.
  • Detailed analysis in Sri Lanka has resulted in claims that greater productivity and reduced costs result in bigger profits for farmers.
Photo courtesy of Amrik Singh
SRI methods frequently result in dramatically improved plant and root growth (SRI rice, left – conventional rice, right). Photo courtesy of Amrik Singh

It is logical that as impressive results for greatly increased rice yields from using SRI are reported the technique would be used on other crops.

The extension of SRI practices to wheat, the next most important cereal crop after rice, was fairly quickly seized upon by farmers and researchers in India, Ethiopia, Mali and Nepal. SWI was first tested in 2008 by the People’s Science Institute (PSI) which works with farmers in Himachal Pradesh and Uttarakhand states. Yield estimates showed a 91% increase for non-irrigated SWI plots over usual methods in rainfed areas, and an 82% increase for irrigated SWI. This has encouraged an expansion of SWI in these two states. - Jonathan Latham – Our World 2.0, 24 Dec 2012.

Millet, sugar cane, rapeseed, lentils, soybeans and vegetables such as tomatoes, chillies and aubergines/eggplants are also being cultivated in many parts of the world using similar techniques to SRI – generically known as SCI (System of Crop Intensification). Farmers using the technique and NGOs working in the area have reported large increases in crop yields.

Jonathan Latham, Independent Science News, 3 Dec 2012
Reported increase in SCI crop yields Jonathan Latham, Independent Science News, 3 Dec 2012

Last week a farmer from the village of Sohdih, also in the Nalanda district, claimed to have set a world record for potato-growing using organic/SRI farming. Rakesh Kumar was said by district magistrate Sanjay Kumar Agrawa to have harvested 108.8 tonnes of potatoes per hectare. The harvest, yet to be confirmed by the Indian central authorities, was said to have been verified by experts, scientists and officials. - John Vidal, The Observer, 23 Feb 2013.

Criticisms of SRI

If such a simple technique can produce such impressive results and make a major contribution to solving food shortages as well as increasing the prosperity of farmers in the poorest parts of the world, why has it not received universal acclaim? Most of the criticisms are concerned with the lack of evaluation of the high yields claimed by farmers.

How could the Indian government have confirmed the number after the harvesting was already done? - Professor Yuan Lonping, director-general of China's national rice research centre and holder of the previous record of 19.4 tonnes a hectare for rice production..

SRI is a set of management practices and nothing else, many of which have been known for a long time and are best recommended practice. Scientifically speaking I don't believe there is any miracle. When people independently have evaluated SRI principles then the result has usually been quite different from what has been reported on farm evaluations conducted by NGOs and others who are promoting it. Most scientists have had difficulty replicating the observations. - Achim Dobermann, deputy director for research at the International Rice Research Institute..

Professor Yuan introduced the intensification method to China but claims that an increase in yield of only 10-15% is possible using the technique. Other agricultural researchers have made similar comments and there is no doubt that a long-term evaluation of the technique in a wide range of social and physical environments is needed before an accurate judgement of SRI can be made. It is obvious that there are a number of factors that may have an impact on the level of success that farmers may gain using the technique. Variations in seed and soil quality, the availability of water at appropriate times in the plant growth cycle and appropriate nutrient management will all have an impact on plant growth, as well as the skill and resourcefulness of the farmer. The intensive farming methods used would seem to imply harder work for the farmers and doubts have also been raised about the use of the technique in large-scale farming. Some farmers who are successfully using the technique claim that neither of these things is necessarily true.

SRI gives higher output with less input, but requires very laborious manual work which makes it more suitable for small farms in developing countries. Moreover, SRI should be modified and adapted to suit local conditions, and as experience teaches. - Professor Yuan Longping, Institute of Science in Society, 6 July 2004.

The use of SRI and associated techniques for a range of crops is growing rapidly. A growing number of NGOs, researchers and administrators working together with farmers in Asia, Africa and Latin America have been willing to test SRI and demonstrate its opportunities. The low and intermediate technology associated with the technique means that farmers themselves have begun making improvements in SRI methods and implements, and many have voluntarily undertaken to spread knowledge of the techniques to their peers.

Photo courtesy of Pascal Gnebou.
SRI farmers regularly use, modify and devise a variety of simple equipment — such as the weeder pictured here – often made locally using inexpensive, widely available materials. Photo courtesy of Pascal Gnebou.

Its supporters claim that SRI offers a way of increasing food supply that does not cause damage to the environment and is accessible to the poorest farmer. It is not evangelical about organic methods and recognizes that there is a place for scientific developments in things such as plant technology and microbiology.

The emerging paradigm for post-modern agriculture differs from its namesake in the arts and humanities in that it embraces modern science, rather than being hostile to it. Indeed, post-modern agriculture is the most modern agriculture because it builds upon cutting-edge research in microbiology and ecology:

  • It is not hostile toward genetic improvement, but it does not regard advances in agriculture as being primarily led by the manipulation or modification of genes. Genetic differences are very important for capitalizing on all available inputs, but these differences should be considered in an interactive rather than deterministic fashion.
  • There can be a role for soil nutrient amendments to correct deficiencies or imbalances, so it is not ‘organic’ in a doctrinaire way. It does, however, reject efforts to accelerate plant growth by ‘force feeding’ plants, with large amounts of nutrients. This supply-side approach is generally less effective and less efficient than one which nurtures and supports plants’ demand for nutrients.
- Norman Uphoff, Agriculture Networks, Dec 2006.

Is SRI too good to be true? That question will be answered over the next decade as its long-term use can be evaluated. There is a huge amount of literature on the subject and a wide range of opinions.

Reading and Resources

India’s rice revolution: Chinese scientist questions massive harvests’, John Vidal, The Observer, 23 Feb 2013

India’s rice revolution, John Vidal, The Observer, 16 Feb 2013

Audio slideshow from The Guardian

Information website from Cornell University

Manoj Singh on Agriculture Information website

How millions of farmers are advancing agriculture for themselves’, Jonathan Latham, Our World 2.0, 24 Sep 2012

Informative article on the Institute of Science in Society website asking whether SRI actually works

How millions of farmers are advancing agriculture for themselves’, Jonathan Latham, Independent Science News, 3 Dec 2012

Improvised tools for SRI paddy planting’, M.J. Prabu, The Hindu, 3 Jan 2013

World Bank report on SRI use in the Philippines

The System of Rice Intensification and its implications for agriculture’, Norman Uphoff, Agricultures Network, Dec 2006

Cornell University report on SRI use in Senegal, Dec 2008