Science in Society Archive

Rice Wars

Rice, the staple food crop for more than half the world’s population, among them the poorest, is the current target of genetic modification, an activity that has greatly intensified after the rice genome was announced two years ago (see "Rice is life" series, SiS 15, Summer 2002). Since then, all major biotech giants are investing in rice research.

At the same time, a low-input cultivation system that really benefits small farmers worldwide has been spreading, but is dismissed by the scientific establishment as "unscientific". This is one among several recent innovations that increase yields and ward off disease without costly and harmful inputs, all enthusiastically and widely adopted by farmers.

A war is building up between the corporate establishment and the peoples of the world for the possession of rice. The food security of billions is at stake, as is their right to grow the varieties of rice they have created and continue to create, and in the manner they choose.

Does SRI Work?

The first reality check of a low-input rice-growing system took place two years ago and more successes documented since. Dr. Mae-Wan Ho reports

The clearest sign that SRI works, if not miracles, then certainly well enough, is the number of participants drawn to the first in-depth international assessment of it.

Nearly a hundred people from 18 countries were listed as participants in the 192-page proceedings of the 4-day conference, which took place in Sanya, China, in April 2002. More than three-quarters were scientists, with policy-makers, representatives of non-government organisations, international organisations, private companies and farmers making up the rest. Participants from the host country China made up more than half of the total, and all were scientists from prestigious rice research institutes, agriculture academies or universities.

The conference was convened, not to assess whether SRI works - for that was the experience of almost everyone who presented papers at the conference - but to assess across nations, "the opportunities and limitations" of a practice that "can give yields about twice the present world average without reliance on new varieties or agrochemicals."

The conference did bring together a substantial body of evidence from around the world that SRI can increase yield in a variety of soils, climatic conditions, with various local adaptations, and using both indigenous and commercial 'high yielding' rice varieties.

SRI has been "practice-led" thus far, but participants at the conference felt it was time for scientists to catch up and research the knowledge-base, so that a healthy dialectical relationship between practice and knowledge can be achieved to help advance this important project of delivering food security and health to more than half the world's population.

Since then, more successes have been reported, leaving the scientific establishment even further behind (see "Fantastic rice yields fact or fallacy?" this series).

Super-yields in Madagascar

The province of Fianarantsoa, situated in the south-central highlands of Madagascar, now lays claim to the highest yielding rice-fields in the world since the introduction of SRI in the 1990s.

The highlands are subtropical, with annual rainfall averaging 1375mm. The rainy season occurs during the hot months in the year, where the average temperature rises above 20C. The Fianarantsao region is often affected by cyclones during the rainy season.

Fianarantsoa attained rice yields of more than 8t/ha in the first year of applying SRI methods, up from the 2t/ha national average. SRI in this region is increasingly linked with the use of compost in rotational cropping with potatoes, beans or other vegetables in the off-season. In the second and succeeding years, the residual and cumulative effects of soil organic matter from composting increased yields still further, to 16t/ha. By the sixth year, yields as high as 20t/ha were measured on farmers' fields in Tsaramandroso, Talatamaty and Soatanana.

Bruno Andrianaivo, senior agronomist of FOFIFA (National Centre for Applied Research on Rurual Development in Madagascar) emphasized that such high yields cannot be achieved immediately, but requires the cumulative effects of 6 years under SRI.

However, simply on the conservative figure of 8t/ha yield from SRI practice Andrianaivo estimated a net return to the farmer of 5 million Fmg (about US$770), compared with around 250 000 Fmg (less than US$40) for conventional practice.

Acceptance in China

Professor Yuan Longping of China National Hybrid Rice Research and Development Centre played a key role in creating high-yielding super-hybrids throughout the late 1990s and early 2000s by conventional breeding methods. His Centre had already broken all records in boosting rice-hybrid yields when he first heard about SRI from a paper written by Norman Uphoff of Cornell International Institute for Food, Agriculture and Development (see "Fantastic rice yields fact or fallacy?" this series).

Yuan conducted the first trial of SRI in his Centre's station in Sanya from winter 2000 to spring 2001. Only three varieties yielded above 10t/ha, and SRI gave an average increase of around 10% over the conventional practice. The following year, tests were conducted in the summer at the Centre's station in Changsha. Two varieties yielded 12t/ha, and one 12.9t/ha, a record for the Centre so far. This encouraged more Chinese scientists to conduct SRI research. Of the 8 locations in which his Centre was involved, 5 locations got good results, with yields over 12t/ha.

Since then, trials by a private sector company, the Meishan Seed Company in Sichuan Province, using a modified SRI method, achieved yields of 15.67/ha and 16t/ha in two different plots, both new records in Sichuan Province (yield in the conventional field was 11.8t/ha).

Yuan's preliminary evaluation of SRI is enthusiastic: "SRI is a promising way to increase rice yield and to realize the yield potential of any variety…whether high-yielding variety (HYV) or local variety." He confirmed that the method can promote more vigorous growth of rice plants, especially tillers and roots, and noted in addition, less insect and disease problems during the vegetative growth stage, and that there are definite varietal differences in response to SRI practices: those with strong tillering ability and 'good plant type' are more favourable for SRI cultivation. "SRI gives higher output with less input, but requires very laborious manual work which makes it more suitable for small farms in developing countries" he said. Moreover, SRI should be modified and adapted to suit local conditions, and as experience teaches.

For China, he recommended a long list of modifications, including using tray nurseries to raise the young seedlings instead of flooded seedbeds, so as to reduce the trauma of transplanting; and controlling tiller-formation, for although increased tillering gives many more rice-forming panicles, the percentage of productive tillers falls off with the number of tillers, so there is a optimum maximum number.

He definitely thinks there is scope for combining genetic improvement with SRI methods. For example, breeding plants with a strong ability to form tillers would be appropriate for improving the response to SRI.

Detailed analyses of the trials were presented in several multi-author research papers. For example, the economic benefits of applying SRI methods were estimated for the hybrid rice Liangyoupei 9, which came both from savings and increased yield. The amount of hybrid seed needed in SRI methods was only 3 - 4.5kg, which represented a seed saving of 8.3 - 10.5kg and nursery saving of 90%, thereby reducing the cost by 215 Yuan/ha. As only compost was applied, the saving on the 10-12t/ha fertilizer that would have been used was 1 200Yuan/ha. The saving on water, some 3 000 tonnes, was about 150 Yuan/ha. The total saving with SRI methods thus amounted to about 1 565 Yuan/ha. Add to that a 15% increase in yield (1.5 tonnes/ha) and the farmer gets a total additional profit of about 3 000 Yuan/ha (about US$ 360).

The Sichuan Academy of Agricultural Sciences has done SRI trials for three years in succession. Its 2003, trials showed an average SRI yield of 13t/ha. Another series of trials in 7 regions of Zhejian Province using 8 varieties all resulted in increased yield under SRI; the average increase being 1.5t/ha over already high-yielding controls.

The China National Hybrid Rice Research and Development Centre introduced hybrid varieties into Africa and recommended that they be used with SRI methods. In 2003, a 9.2t/ha yield was obtained with hybrid GY032 in Guinea under SRI methods, which was 4 times the national average yield.

SRI in Gambia

The Gambia, a small country (11 700km2) in West African, is a 50 km-wide ribbon of land extending eastward from the coast, bisected by the River Gambia and surrounded on three sides by Senegal. Its annual rainfall is 900 to 1400mm; the rainy season between late May and early October. Rice is the staple of the country and there are 5 very different production systems: upland, lowland rainfed, irrigated (pump and tidal), freshwater swamps and seasonally saline mangrove swamp.

Annual rice consumption averages 70 to 110kg per capita; domestic production lags behind by 60%, and the balance is met by imports. The national average yield of rice is only 2t/ha.

SRI was introduced to The Gambia in the rainy season of 2000 as part of the Ph. D. thesis of Mustapha M. Ceesay in Crop and Soil Sciences at Cornell University in the United States. Farmers were invited to visit the first SRI trial site at the Sapu station of the National Agricultural Research Institute (NARI) in The Gambia before they enrolled voluntarily in the research programme.

During the first year of experimentation, three different plant population densities were investigated with several varieties. Yields ranged from 5.4 to 8.3t/ha. In 2001, plant population densities were investigated alongside fertilizer treatments, and on-farm trials involving 10 farmer households. The on-station SRI trials were conducted under pump irrigation, and on-farm trials under tidal irrigation.

Plant population densities investigated were 20cm x 20cm, 30cm x 30 cm and 40cm x 40 cm. Two rice varieties were used, and instead of compost, three fertilizer treatment rates were assessed: NKP in the following proportions: 70-30-30 (national recommended), 140-30-30 and 280-30-30. All trials took place in the lowland.

The on-station trials indicated that 30cm x 30cm spacing did not decrease yield over the 20cm x 20cm, and was hence recommended to the farmers for the on-farm trial. Fertilizer treatments indicated that under SRI, the nationally recommended lowest rate was as effective as doubling the rate, while tripling the rate gave higher yields, but it was not economically profitable.

The on-farm trials, conducted in a communal tidal irrigation scheme, gave "exciting" results, "a tripling of yield" on average, 7.4t/ha compared with 2.5t/ha obtained with farmers' current practices. Some farmers experienced more than five-fold increases, from 1.6 to 9.0t/ha in one case, and 1.4 to 8.0t/ha in another.

But there are problems facing the farmers in land preparation. Farmers in The Gambia still do not have a well-developed culture of water control. Fields are simply kept flooded after transplanting until the rice plants mature, and fertilizer application and weeding are done under submerged conditions. These practices will conflict with the adoption of SRI, but the yield increases may be a sufficient incentive for farmers to overcome these problems.

SRI in other countries

Many countries reported remarkable increases in yield. Salinda Dissanayake, Member of Parliament in Sri Lanka, personally tested SRI in his own rice field of a little more than 2 acres for four seasons, using seeds of various varieties. He got the highest yield of 17t/ha with BG358, a variety developed by the Sri Lankan rice researchers. Even with local varieties such as Rathhel and Pachdhaiperumal, usually much lower yielding at ~2t/ha, impressive yields of 8t/ha and 13t/ha were obtained.

Dissanayake formed a small group to inform farmers of SRI; and farmers who took up SRI from 18 districts have doubled their yields on average.

"These yields were obtained with less water, less seed, less chemical fertilizer, and less cost of production per kilogram …among SRI users, we find people of many different income and educational levels and different social standing, including many poor farmers having only small plots of land, farmers with moderate income, some agricultural scientists, and a few administrators, businessmen and political leaders who practice it with their own convictions." Dissanayake said.

H. M. Premaratna, a farmer from the Ecological Farming Centre, Mellawalana, Sri Lanka, backed up the enthusiasm of his Member of Parliament, and has personally provided training on SRI to more than 3 000 farmers by 2002. "From my experience, I have observed that the rice plant becomes a healthier plant once the basic SRI practices are adopted," he said.

Reports from 17 countries in 2002 showed that three-quarters of the cases gave a significant yield advantage of at least 20 to 50% increase, and although the super-yields reported from Madagascar have not been obtained elsewhere, some farmers in Cambodia and Sri Lanka have come close. Overall, the conventional systems yielded 3.9t/ha, very close to the world average for rice production. The average for all the SRI yields reported was 6.8t/ha.

A report from the Philippines not only documented yield increases over several successive growing seasons since 1999, but also a reduction of crop pests such as rats and brown and green leafhoppers, carriers of the dreaded rice tungro virus disease. This was attributed to the increased spacing of plants, allowing more sunlight to penetrate even the base of the plant, exposing the hoppers, which detest and avoid sunlight.

In Cambodia, SRI is spreading very rapidly. Only 28 farmers were willing to try SRI in 2000, by 2003, this number had grown to almost 10 000 and in 2004, 50 000 farmers are expected to adopt it.

Perhaps the greatest testament that SRI works is the increasing number of farmers that have adopted the practice.

Article first published 06/07/04


  1. Assessment of the System of Rice Intensification (SRI), Proceedings of an International conference held in Sanya, China, April 1-4, 2002, Cornell International Institute for Food, Agriculture and Development
  2. Uphoff N. Facts and fallacies regarding "Fantastic yields in the system of rice intensification". Field Crop Research.

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