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While the research projects and collaborative efforts discussed in the preceding chapter made essential contributions to understanding how and why SRI methods affect crops’ performance and health as they do, most of the knowledge generated during the 15 years following the Sanya conference came from individual researchers who gradually built up a substantial body of knowledge on SRI in the published scientific literature. This can be seen from as listing of over 1,300 journal articles, theses, proceedings, conference papers, and reports on SRI, most posted or linked on the SRI-Rice website to be easily accessible.[1]

Hundreds of individuals have contributed to this literature, so only some of them can be mentioned here, focusing on the work of colleagues who were among the first to undertake publishable research on different aspects of SRI in their respective countries. This work was undertaken out of a combination of personal curiosity, scientific interest, and the promptings of idealism, anticipating that their efforts could benefit producers and/or consumers and/or the environment, but preferably all three.

It was a personal observation that most of the researchers who involved themselves with SRI differed from their peers by being more field- and farmer-oriented than other scientists, enjoying face-to-face interaction with farmers and having evident respect for them. This observation cannot be substantiated with data, but it was something noted when I made visits to the field with them.[2]

Most of the contributors were, as might be expected, researchers at universities or in research institutions; however, some were government personnel or private-sector colleagues.[3] Curiosity is not limited to academia, and there are various ways in which knowledge generated can be put to use apart from journal publication. What follows are report on some of the most interesting and often unexpected findings that expanded our understanding of SRI beyond its origins.



The first evaluation of SRI done outside Madagascar was conducted at Nanjing Agricultural University in 1999 under the leadership of Dr. Cao Weixing, then vice-president of the university (Chapter 37).[4] The yield results obtained in their SRI trials were not particularly remarkable, Cao told me during a CIIFAD workshop in Yangzhou City in August of that year. His SRI trials had given yields of 9.2 to 10.5 tonnes per hectare. But such yields are already being attained by planting hybrid varieties and using high doses of chemical fertilizer, he said.

However, Cao continued, SRI is interesting to Chinese scientists. Why? Because they cannot get such high yields when using only half as much irrigation water as with conventional rice cultivation. The rice sector in China was already encountering serious constraints due to limited water supply and declining water quality. So, this made SRI attractive.

At the Sanya conference in 2002, researchers from Nanjing Agricultural University reported on four experiments.[5] Two of their most interesting results helped to advance our understanding of SRI. Under SRI management compared with standard methods of rice cultivation in China, it was seen that SRI rice plants translocated significantly more assimilates (products of photosynthesis) to their leaves, stems and sheaths, a phenotypical difference.

Under experimental conditions, SRI plants had 97% more dry matter in their leaves, stems and sheaths, 74% more carbohydrates, and 3% more nitrogen. Further, the conversion percentages reported by NAU scientists for these factors were also greater: 86% higher for dry matter, 53% for carbohydrates, and 60% for nitrogen. This research quantified some of the factors contributing to the greater size and vigor that were being seen in SRI-grown plants.

Measurements were also made of the differences in the oxygenation that took place within rice plants’ roots, a measure of roots’ metabolic activity. This could be assessed by analyzing the levels of alpha naphthalamine (α-NA) in the roots. When comparisons were made between the roots of SRI and conventionally-grown plants at different stages of their growth, SRI roots had 1.9 times more root oxidation activity at the tillering stage (N-n) than did the control plants, and 2.3 times more at the next stage, spikelet differentiation (n-2). At heading (panicle emergence), the oxygenation activity in SRI plant roots was double (2×), and at maturity, it was 2.9 times higher, as seen in the figure below. Such measurements provided early evidence that SRI management practices were having substantial and demonstrable effects on the physiology of rice plants.

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Scientists at the China National Rice Research Institute located on the outskirts of Hangzhou, led by senior rice scientist Zhu Defeng, started their SRI evaluation trials in 2000 after learning about SRI from the ILEIA magazine article mentioned in the preceding chapter. The results of their research were also reported to the Sanya conference.[6] Some of the findings of Dr. Tao Longxing were shared a colorful figure in Chapter 4.

After the Sanya conference, Zhu began serving informally as a volunteer coordinator for a nascent national network of Chinese researchers on SRI. He also worked with Wu Lianghuan at Zhejiang University, located coincidentally and conveniently in Hangzhou. Wu, an environmental scientist concerned about nitrogen fertilizer’s pollution of groundwater, had become interested in SRI during a visit that he had made to Cornell in 2004. Below is a picture of Zhu Defeng visiting an SRI field in Tien Tai township of Zhejiang province, and also of the signboard that CNRRI had erected nearby.

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The results of their initial research prompted CNRRI scientists to do two seasons of systematic trials, 2006 and 2007, that evaluated SRI methods on their own experiment station. Using two popular hybrid varieties, they compared what they called ‘standard rice management’ (SRM) using 30-day seedlings and continuous flooding, with a version of SRI that included 15-day seedlings, alternate wetting and drying, and more organic fertilization.[7] Zhu’s colleague, Lin  Xianqing, took a lead role in conducting this evaluation.

All of the comparison trials received the same amounts of nutrient supplementation (N, P and K) with the amount of nitrogen in the respective treatments being varied from 120  kg to 210 kg per hectare.[8] The N was provided in two different ways: in the SRI plots, 50% of the N came from an organic source (rapeseed cake), while all of the N provided in the SRM trials was inorganic.

Weed control was the same for all of the plots, using herbicides, which meant that the SRI plots did not have soil-aerating weeding. This could be why the yield advantage for SRI, although significant, was only 17%. The density of rice plants per m2 was experimentally varied from 150,000 plants per hectare to 180,000 and 210,000.[9]

The most important result was the demonstration that with SRI practices, paddy rice yields were higher with reductions in seed, water, and N fertilizer. This meant that Chinese farmers were (and are) wasting seed, wasting water, and wasting fertilizer. They could produce more grain by expending less of these resources, rather than more. Cutting N fertilizer applications would have the additional benefit of improving both soil and water quality.

The bar-graph figure below shows how transplanting younger (and many fewer) seedlings makes it possible to produce more grain with less expenditure on water and fertilizer. (Other evidence suggests that the SRI yield advantage could have been still greater if there had also been soil-aerating weeding.) The figure shows that even in trials with the highest plant density, 210,000 plants per hectare (right-hand bars), SRI outyielded standard methods by 0.5 tonne per hectare, even though the SRM plots received more water and more chemical fertilizer. With 30% fewer plants and with less water and less fertilizer, the yield advantage of (incomplete) SRI methods was increased to 2.5 tonnes (bars on left). Thus, making less expenditure on seeds, water and fertilizer gave five times more advantage in yield.[10]

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Looking across the three different plant densities with higher or falling lower of N fertilization, the researchers found that rice plants grown under standard rice management gave higher grain yield when, with larger applications of N, their plant density was increased from 150,000 to 210,000 per hectare. However, SRI plant phenotypes had an opposite response. Their yield with increasing applications of N fertilizer rose when the density of plants was decreased. Fewer plants thus produced more rice per hectare.

The highest yield when using standard methods (8.6 tonnes per hectare) was achieved with 210 kg of nitrogen fertilizer and 210,000 plants per hectare. This yield was, however, 5% less than the yield attained with (mostly) SRI methods, 9.0 tonnes per hectare. This high yield was achieved with just 120 kg of nitrogen and 150,000 plants per hectare. The SRI plots produced more grain with 43% less N fertilizer, 30% less seed, and about half as much water.

This was the most clear-cut demonstration up to that date that lowering the inputs of seed, water and N fertilizer would not diminish yield, but would increase it instad. These results were reinforced by research conducted concurrently at Zhejiang University by a PhD student Zhao Limei under the supervision of Wu Lianghuan in cooperation with Zhu Defeng.[11]

Such evidence, despite coming from the country’s own national rice research institute, unfortunately did little to change thinking and practice in China. Indeed, there were no evident ‘ripples’ from the research even though it was carried out by senior Chinese rice scientists including the Institute’s director-general, Dr. Cheng Shihua!

In Sichuan province of China, senior scientists at the Sichuan Academy of Agricultural Sciences, Zheng Jiaguo and Lu Shihua, and at Sichuan Agricultural University, Ma Jun, undertook research on SRI after learning about this methodology from Prof. Yuan Longping in 2001.[12] The farm manager on a seed-multiplication farm in Meishan associated with Prof. Yuan Long-ping, Liu Zhibin, developed a modified SRI planting scheme that further enhanced SRI yields. This innovation was evaluated and reported by SAAS rice scientists.

Called ‘the triangular method’ of SRI crop establishment, this alternative employed much wider spacing between hills than previously recommended for SRI (30x45 cm), reducing the number of hills per m2 by half. But in each hill, three plants, instead of one, were arranged in a triangular pattern with 10-12 cm spacing between the plants, which increased the plant population per m2 by about 50%. This version followed the SRI principle of wider spacing to give rice plants’ roots and canopies more space to grow and spread, but this was achieved with a configuration of plants that made plant density higher.[13]

Below are pictures of ‘triangular’ SRI in Sichuan. On the left we see the stumps of three plants per hill after harvesting. On the right are rows of growing rice plants; on the left half of the picture are hills where the three seedlings were spaced apart, while on the right side, they were clumped together as done with conventional transplanting. The more vigorous growth of plants in the rows on the left is quite evident.

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In his evaluation of the alternative at the Sichuan Academy of Agricultural Sciences, Zheng found that SRI methods by themselves increased rice yields by 20% over ‘best practices’ in Sichuan, giving 10.42 tonnes per hectare compared with 8.64 tonnes from current practice, already a very high yield. When the ‘triangular method’ when used together with other SRI practices, the resulting yield was 13.39 tonnes per hectare, an increase of 55%.[14] This was an important innovation within the SRI framework that emerged within China once farmers and researchers started taking the principles of SRI seriously and seeking to improve the practices that applied these principles.

Like Zhu and Lin in Zhejiang province, Zheng and Lu worked with the Provincial Department of Agriculture in Sichuan to get SRI diffused there. Provincial department data show that SRI use expanded in Sichuan from 1,133 hectares in 2004 to 383,533 hectares eight years later.[15] Ma’s data documenting the improvements in grain quality achieved with SRI management are considered in Chapter 11.

While the number of Chinese researchers working on SRI has not been very large considering the huge size of their country, a substantial body of research on SRI was quickly built up in this country based on a combination of individual and institutional initiatives.[16] A meta-analysis of the published evaluations of SRI by several dozen Chinese researchers calculated that ‘good’ use of SRI methods, even without complete use as recommended, conferred a yield advantage of 20% over what researchers at the time considered as best management practices.[17]


Some of the first research on SRI was done in Thailand by Dr. Phrek Gypmantsiri, director of the Multiple Cropping Center at Chiangmai University.[18] Unfortunately, his results were not encouraging as the SRI yields were 10% to 40% lower than those obtained with standard methods.[19] This was the poorest SRI performance reported at the Sanya conference.

A few years later, Abha Mishra, an Indian national studying for a PhD at the Asian Institute of Technology near Bangkok, who had done a master’s degree in India and then research work in Australia, took an interest in SRI and focused her thesis research on this innovation, as described in her mini-memoire. Because of her and her husband’s involvement with the farmer field school methodology promoted by FAO’s Integrated Pest Management program, Abha built farmer participation into her research, while also doing pot experiments in AIT greenhouse facilities that enabled her to make precise measurements of root and plant growth under controlled conditions.[20]

From her thesis’s review and analysis of relevant literature, Abha wrote with her advisors the first review article published on mechanisms that could explain SRI impacts (see Annex to Part I) and that also considered the potential contributions of farmer participation.[21] This was followed by a number of other articles published from her thesis research.[22]

Among her important contributions, Abha documented the superior growth of rice seedlings grown in an unflooded nursery and then transplanted at a young age (12 d) into an unflooded field rather than into a flooded field. Conversely, her trials showed that older seedlings (30 d) raised in a flooded nursery before being transplanted will grow a little better in a flooded field than in an unflooded one.

Abha’s research also documented the inferior performance of older rice seedlings grown in a flooded nursery and transplanted into a flooded environment compared to seedlings grown in an unflooded, garden-like nursery, and then transplanted into unflooded fields at a young age. This helped to explain why conventional rice cultivation practices arose and persisted. It is logical for farmers to transplant older seedlings because such plants look more impressive when transplanted. But also, older seedlings if grown in a flooded nursery and transplanted into flooded fields, instead of into unflooded fields, give better results.

However, Abha showed that even better yields result from transplanting younger seedlings grown in unflooded nurseries into fields that are not inundated. Aerobic soil is better for rice plants in both nurseries and fields. But unsaturated field soil will not necessarily be the best for seedlings that have been raised in nursery soil that was kept flooded.

The kinds of differentials that Mishra found in her controlled trials are presented in the bar graphs below. These figures show the interacting effects of seedling age (12 vs. 30 days), nursery (dry vs. wet), and water regime (unflooded vs. flooded). This multi-variable analysis confirmed the greater productivity of SRI’s recommended practices.

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Plants’ tiller development at 45 days after transplanting with interaction effect of different factors. Top: Nursery seedbed dry (DSB) or wet (WSB) interacting with seedling age (12 days old or 30 days old), and bottom: water regime flooded (FL) or non-flooded (NFL) interacting with seedling age. N=16. Error bars show s.e.

Like the research by Chinese scientists reported above, such multi-factorial analysis helped to explain the effects of different aspects of SRI practice, not evaluating all of the practices at the same time as was done in the factorial trials in Madagascar (Chapter 7). Abha’s detailed knowledge of these various factors, as well as her work with farmer participatory approaches, prepared her to formulate and lead, with her husband Prabhat Kumar, the EU-funded project in Southeast Asia for upland areas in the Lower Mekong river basin, discussed in Chapter 8.


As in Thailand, the initial evaluation on SRI in this country was not successful.[23] Fortunately, Ngo Tien Dung in the Ministry of Agricultural and Rural Development (MARD), who had given national leadership for refining and spreading integrated pest management for rice in Vietnam, learned about SRI through the FAO IPM program in Indonesia, and he began systematic evaluation trials for the Ministry in three provinces in 2003. Within a year, SRI research was also started at Thai Nguyen University through the initiative of Hoang Van Phu, as discussed below, beginning field applications in northern provinces of the country. By 2006, Dung’s testing had expanded to 17 provinces throughout the country with 3,450 farmers participating in trials.

The on-farm comparison trials under Dung’s IPM program did not show very large increases in yield with SRI methods under Vietnamese conditions, only 9% to 15% improvement. But SRI methods reduced farmers’ costs of production enough to boost their net income from rice production by more than US$ 125 per hectare. Making reductions in chemical fertilizer and pesticide use possible with SRI management was in line with the government’s goal of reducing adverse environmental impacts from agriculture. Phu’s research results in the north showed SRI methods improving rice yields there by 13% to 28% over conventional practice.

In 2007, Dung presented his data to the Ministry of Agricultural and Rural Development.[24] This had more impact than publishing the data in a journal because it elicited an official endorsement of SRI, authorizing the use of government resources to promote SRI.[25] Within four years, the Ministry reported that the number of farmers using SRI methods in Vietnam had surpassed 1 million.[26] Although Dung’s research had very practical use and impact, it also had important knowledge payoffs, particularly for understanding SRI reductions of the incidence of pests and diseases, as seen in Chapter 12.

The main university engagement with SRI evaluation as noted above was at Thai Nguyen University through the initiative of Phu, a senior lecturer and rice specialist there.[27] Subsequently, there was considerable government research interest in SRI seeking to lower greenhouse gas emissions from rice paddies, as discussed in Chapter 12. But this was more a matter of institutional than of individual efforts to explore and validate the potentials of SRI and to understand its workings.




Much of the Japanese research on SRI has been published in Japanese language so it is not widely accessible. The Japan Association of the System of Rice Intensification (J-SRI) after it was established in 2007 began holding meetings several times a year, usually at the Tokyo University of Agriculture and Techology, to hear research reports and share new knowledge, and occasionally to host SRI colleagues from other countries. J-SRI became one of the most organized loci for SRI knowledge generation and spread.[28] In particular, it worked with colleagues in Indonesia and Taiwan on SRI research in those countries. The impetus for establishing J-SRI came from Shuichi Sato’s experience with SRI in Indonesia, an example of civil society-university cooperation.

Research in Japan on SRI was encouraged by the early interest in this innovation expressed by Prof. Takeshi Horie, one of the country’s senior rice scientists based at the University of Kyoto, who subsequently became director-general of the National Agricultural Research Organization. In 2005 he published an article with several colleagues who took SRI seriously, showing how many of SRI’s practices corresponded with those used by the Japanese farmers who won the country’s national prize for highest rice yield during the 1950s.[29]

Horie subsequently sent one of his PhD students, Yasuhiro Tsujimoto, to Madagascar to study the super-yield of Ralalarison (Chapter 10). This study was a useful contribution to the literature on SRI, although its study of soil fertility, which highlighted the importance of enhancing soil organic matter, did not include any examination of the soil’s microbiology, which is probably part of the explanation for the high yields.[30]

Much of the SRI knowledge generation from Japan that is published in English came from or with the support of Professors Eiji Yamaji and Masaru Mizoguchi at the Tokyo University of Agriculture and Technology. Both were founders and office-holders for J-SRI. Yamaji and a PhD student from Nepal, Tejendra Chapagain, were the first to document through systematic measurements how SRI practices make rice crops less susceptible to lodging from the wind and rain of storms, documenting also SRI crops’ greater resistance to pests and disease.[31]

The first research on SRI’s reduction of the emission of greenhouse gases from paddy fields was done in 2008 by Dorothy Kimura from the Tokyo University, working with Iswandi Anas in Indonesia. Her research documented an expected reduction of methane (CH₄) emissions under SRI management, but also reported that with SRI practices, there could be little increase of even reduction in nitrous oxide (N₂O) emissions as well. The lower levels of greenhouse gas emissions reported in this study were related to the greater use of organic fertilizers rather than inorganic nutrients as well as use of biofertilizers that promote beneficial microbes in the soil. Below is the introductory slide from Dr. Kimura’s powerpoint presentation on her research.

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Kimura’s study concluded that with SRI methods, the increase in N2O emissions from rice paddies was within the range measured in conventionally-managed fields, i.e., there was not a significant increase.[32] As discussed in Chapter 12, greenhouse gas emission levels can vary widely, depending on many factors. Overall, Dr. Kimura’s initial findings have stood up very well for more than a decade.



Most of the published work on SRI from Korea came from Joongdae Choi and colleagues at Kangwon National University. In this country, as in Japan and Taiwan with their relatively high rice yields, increasing the yield of rice has not been a prominent concern. However, there is interest in reducing the adverse environmental impacts of current rice production methods. Accordingly, Choi and his colleagues focused on the reduction of greenhouse gas emissions, finding desirable effects of SRI practices similar to those measured by Kimura and others.[33]

Choi and his colleagues were the first to study the effects of SRI management on water quality, measuring the reductions in non-point source (NPS) pollution that result with SRI vs. standard paddy production methods. They found that the runoff from paddy fields managed with SRI practices had reductions ranging from 27% to 46% in suspended solids, in biochemical and chemical oxygen demand, and in total N and total P. These improvements in water quality are particularly relevant in Korea where many water bodies and groundwater reserves are adversely affected by chemical-intensive rice production.[34]


Both research on and the practice of SRI began later in this country than elsewhere in Asia. Researcher’s engagement with SRI here was stimulated by interaction with J-SRI members from Japan who brought SRI ideas to Taiwan. Here as in Japan and Korea, where yields are already relatively high and rice production is heavily subsidized by the government, SRI’s potential for increasing yield has not been very motivating. However, SRI’s higher factor productivity and its water-saving possibilities were both positive considerations.[35]

Also, SRI’s beneficial impacts for environmental quality, particularly reducing water pollution, plus the attraction of producing the country’s staple food without the use of agrochemicals, sparked interest in Taiwan, even if the concerns that originally shaped SRI were not very relevant there.




Researchers in this country have been among the most active in advancing SRI knowledge within their region and for use beyond. Iswandi Anas and Budi Indra Setiawan at the Bogor University of Agriculture (IPB) took a lead in conducting research on SRI and took initiative to establish an Indonesian Association for SRI (Ina-SRI) in January 2008. Both served in turn as the coordinator for the Ina-SRI network.[36] From the outset, members of this network were in communication and cooperation with J-SRI colleagues in Japan, and many of the publications on SRI from Indonesia were written jointly with Japanese scientists.[37]

Iswandi as head of IPB’s Soil Biotechnology Laboratory initiated research on soil biology aspects of SRI in Indonesia, such as cited in Chapter 5. Some of the most interesting knowledge that he contributed has been on SRI’s potential for ratooning, referred to in Indonesia as Salibu. This involves letting rice plants regrow after their panicles and tillers have been harvested, rather than removing the plants and replanting the field. A second crop can then regrow and be harvested from the same rootstock.

Since the roots of conventionally-managed rice plants degrade due to lack of oxygen, the second yield from such plants is usually not very high, having little supporting root structure. While the cost of replanting can be saved by letting the plants regrow for another harvest, farmers have usually found it more profitable to replant their rice paddies each season and get a higher yield from the new plants, especially where land is relatively scarce and has substantial opportunity costs.

With SRI management, ratoon cropping becomes more productive because the plant have larger and longer-lived root systems (Chapter 4). Iswandi showed that with SRI methods, there is less drop-off in yield, and some yields from second (ratooned) SRI crops have matched the first crop’s yield. SRI can thus make ratooning profitable because its second-season costs of production are much lower.[38]

Setiawan has engaged in research on factors that raise rice productivity while enabling SRI rice paddies to emit fewer greenhouse gases. This research has highlighted the interactions among water level, soil moisture, acidity (pH), and temperature.[39]

The most ambitious knowledge generation on SRI in Indonesia came from a private sector team working under Ministry of Public Works auspices, as reported in Chapter 7. Under the direction of Shuichi Sato, the leader of a technical assistance team for the Japanese consulting firm Nippon Koei, massive amounts of data were collected over six seasons from over 12,000 on-farm comparison trials in irrigation schemes in eight provinces of the eastern part of the country.

One of the most useful things learned from this work in eastern Indonesia was that individual farmers within large-scale irrigation systems, by making certain in-field modifications (drainage channels, raised beds), could keep their soil sufficiently aerobic to get good SRI results, even when the water management regime for the whole irrigation system had not been modified for SRI requirements.[40]

Although this SRI initiative was undertaken under the aegis of a private foreign company working with a national ministry, Sato’s initiative in communicating and cooperating with university, NGO and government agencies, meant that this work done in the eastern part of Indonesia boosted SRI development at the national level.[41]


Several Cambodian universities undertook research projects on SRI in the mid-2000s, but without consistent or conclusive results. Their initial efforts to generate knowledge did not develop into any sustained knowledge creation.[42] In this country, most of the SRI area does not have irrigation facilities, so considerable practical experience has been gained with rainfed versions of SRI, but this has not been documented and disseminated systematically. Cambodian experience did show, however, how SRI can and should evolve beyond its irrigation-based origins.

About 10% of Cambodia’s rice area is cultivated with what is called deepwater rice. This is rice that is grown in the rainy season when rice paddies have 1 meter or more of standing water. This makes it impossible to have aerobic soil conditions. A number of local rice varieties have evolved the capacity to elongate their leaves and stems rapidly so that they can keep their leaves above the water surface and sustain photosynthesis as the water level rises in flooded paddy fields. The stems of some of these varieties of ‘floating rice’ can grow to be as much as 4 meters long, enabling their leaves to keep functing during the maximum flooding period.[43]

Field staff from the NGO CEDAC working with farmers found that by adapting SRI methods to this particular agroecosystem, farmers could increase their low yields (1-2 tonnes per hectare, or less) by 25-50% just by introducing the early transplanting of rice seedlings and wide spacing. This knowledge benefited very poor farmers and showed again how adaptable SRI’s principles can be for diverse settings. Practical if not published knowledge has also been gained in Cambodia on the linking of SRI activities to value-chain initiatives and on the integration of SRI into diversified farming systems, discussed in Chapters 17 and 20.


Much as in Cambodia, there has been more focus here on how to capitalize on SRI opportunities than on understanding how and why these capacities arise. It is worth noting that the first study done outside of Madagascar on phyllochrons with SRI rice (Chapter 6) was conducted by an Ethiopian PhD student at the University of the Philippines at Los Baños as early as 2003-04.

Mulu’s research confirmed the observations in Madagascar that phyllochron length is shortened by transplanting young seedlings, 8 or 15 days old, compared with 20 or 25 days, and by widening the spacing between plants. This was evaluated with two rice varieties. Mulu found that the shortening of phyllochrons was associated, as expected, with more tillering, more filled spikelets, and higher grain weight.[44]



Research on SRI got a later start here than elsewhere in the region, but with the initiative of Anizan Isahak at the National University of Malaysia (UKM), a group of faculty and student researchers became active in producing studies on SRI.[45] As noted in Chapter 5, one of the most productive researchers who has added to our understanding of SRI was an Indonesia PhD candidate in microbiology at UKM. Febri Doni has done extensive work on the interaction of beneficial soil microorganisms with the changes in growing environment for rice that are introduced by SRI practices.[46] He further undertook transcriptomic studies that add to our knowledge of the molecular-biology underpinnings of SRI.




Alapati Satyanarayana, director of extension at the state agricultural university for Andhra Preadesh (ANGRAU), contributed in several ways to our understanding of SRI, as did T.M. Thiyagarajan, director of the Center for Soil and Crop Management at the Tamil Nadu Agricultural University, as noted in Chapter 8. The WWF-ICRISAT project, also described in that chapter, also added significantly to the SRI knowledge base. Contributors to this project included Mahender Kumar and colleagues at the Indian Institute of Rice Research, despite an initial lack of enthusiasm from its parent Indian Council for Agricultural Research (ICAR); and Om Rupela, who has unfortunately now passed on, and a number of other researchers at ICRISAT.

In terms of published research, the most knowledge about SRI coming from India was produced by the efforts of Amod Thakur and his colleagues who conducted research on SRI at ICAR’s Indian Institute of Water Management in Bhubaneswar, Odisha state.

It is ironic that Amod’s engagement with SRI was prompted by his reading one of the most strident rejections of SRI that had been published in the scientific literature.[47] The authors’ conclusion that “SRI has no major role [to play] in improving rice production generally” was based on rather limited empirical foundations: on three small on-station trials in China where SRI methods were not used according to any known SRI protocol, plus on computer modeling that was basically flawed.

What caught Amod’s attention was that SRI yield matched that from rice scientists’ recommended practices, yet this SRI yield was achieved with only one-sixth as many plants per square meter. As a plant physiologist, Amod considered this worth investigating. How could single SRI plants produce as much as six plants grown with conventional methods?

Amod’s curiosity led him to undertake three years of on-station trials at his institute near Bhubaneswar, comparing the results from the SRI practices described on the Cornell SRI website with those from using the recommended practices posted on the website of India’s Central Rice Research Institute at Cuttack. These comparative trials he did without any contact or communication with Cornell or with the CRRI or with IRRI.

Some of the results from Amod’s trials are reported in Chapter 11 where we consider the phenotypical improvements that can be elicited from a given genotype by using SRI methods. Here we consider just one particularly striking finding of his research, as an example of how different the performance of SRI-grown plants can be from standard-practice rice. This finding was quite stunning in the context of water scarcity in India that is caused by the irregularity of rainfall as a result of climate change.

Among the many parameters measured, Amod compared the amount of CO2 fixed in rice plants’ leaves with the amount of water that they transpired during this process of photosynthesis. Such a ratio indicates how water-efficient the leaves are when they are producing carbohydrates for the plant’s metabolism and grain filling.

For each millimol of water that SRI plants transpired per m2 per second, Amod found that they synthesized 3.6 micromols of CO2 per m2 per second. Rice plants of the same variety grown conventionally fixed less than half as much, just 1.6 micromols per m2 per second. So, the SRI-grown plants during their photosynthesis were producing carbohydrates with less than half as much water.[48] This was a phenotypic variation with profound significance for food production under water-limiting conditions.

Scientists at the Indian Agricultural Research Institute (IARI) in New Delhi also undertook research on the effects of SRI on soil biology, on water management, and on the nutritional value of the grain produced, discussed in Chapter 11.[49] 

On the social science side, Shambu Prasad gave leadership on SRI research first while at ICRISATA and then the Xavier Institute of Management in Bhubaneswar and at the Institute of Rural Management at Anand.[50] The total amount of research on SRI that has been done in India is greater than from any other country, although some of it has been somewhat repetitive, focused more on confirming differences in yield than on explaining SRI effects such as Amod and some other Indian researchers have done.


In Nepal during the latter 2000s, there were four master’s students at Tribhuvan University’s Institute of Agriculture and Animal Science at Rampur who wanted to do research on SRI. But given faculty disinterest, they had no institutional support for this. When they contacted CIIFAD, it was able to provide them with small grants that enabled them to conduct research trials and field studies on SRI.[51]

Mostly this research confirmed what was known from previous research in Madagascar and elsewhere, but Krishna Dhital’s research on different methods of crop establishment included interesting analysis of the stages and rates of rice crop growth. His data showed that SRI methods accelerate plant growth fairly uniformly across all of the stages of the rice plants’ reproductive period, grain-forming, and grain-filling. However, there was some evidence of slowing acceleration as the crop approached maturity, as seen in the table below.

Most of the acceleration of plant development occurred during the prior period of vegetative growth. In all of Krishna’s trials, SRI crops matured about 10 days sooner, with 66% higher yield.[52] SRI plants went through all of the stages of growth significantly ahead of the other two practices that were evaluated, farmer’s typical methods and direct-seeding of the rice crop.

Phenological stages of rice as influenced by crop establishment method at Phulbari, Chitwan, Nepal, 2010

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DSR: direct-seeded rice. DAS: Days after sowing; Farmer practice: conventional trans-planted rice; SRI: System of Rice Intensification methods; Table from Dhital thesis (2011).

Also during the 2000s, an agricultural extension officer based at the extension office in Morang district, Rajendra Uprety, began evaluating SRI while he was spreading its use in the terai (plains). Among the things that Rajendra documented was the quicker maturation of SRI-grown rice, as reported in Chapter 11, consistent with Krishna’s results above.

Starting in 2009, Ram Bahadur Khadka, a graduate of the Institute of Agriculture and Animal Science working with a Nepali NGO that operated in western Nepal,[53] started evaluating and extending both SRI and SWI (for wheat) under a program for food security in the region which was funded by the European Union. The positive results, well-documented, led to several published articles on SRI and SWI, including one evaluating how well an indigenous rice variety performed under SRI management.[54]

Subsequently, Ram joined the research staff of the Nepal Agricultural Research Council and was then given a fellowship to do a PhD in plant pathology in the US at the Ohio State University. His research has included some of the first work on SRI-microbial synergies, evaluating the effects of SRI management interacting with the beneficial symbiotic fungus Trichoderma.[55] This research, together with that of Febri Doni, helped to establish a knowledge base for using biofertilizers with SRI.



The most contribution to SRI knowledge from this region has come from Iraq where Khidhir Abhas Hameed, a senior rice researcher at the Al-Mishkhab Rice Research Station near Basra, has been doing SRI research and promotion since 2005 (there is a picture of his on-station trials in Chapter 1).[56] More will be said about his work in Chapter 43, but here we note one of his research-based conclusions that deserved attention throughout the region and wherever irrigation water is a binding constraint on rice production.

Khidhir compared the standard practices rice-growing in Iraq, maintaining 5-20 cm of water on rice paddies, with SRI practice which promotes alternate wetting and drying. He evaluated the effects of having shorter vs. longer intervals between irrigation provision, applying water 3 days or 7 days after surface-water had disappeared from the field’s surface. The latter irrigation schedule put more water-stress on plants, but greatly reduced water consumption.

When paddy fields were wetted either 3 days after the irrigation water provided had been absorbed into the soil or 7 days after this, the crop water requirements were reduced, respectively, by 50% or by 72% compared with conventional flooding. With the schedule of a 3-day period without water standing on the field, SRI methods gave a paddy rice yield that was 12% higher than with continuous flooding, and it required only half as much water!

Because of the arid climate in southern Iraq and associated water stress for the rice plants, the SRI crop with 7-day intervals for irrigation produced 10-15% less rice per hectare than standard practice. However, this was achieved with a three-quarter reduction in the total water consumed!

This yield reduction would not be preferred by individual farmers who have assured access to irrigation water compared to the shorter, 3-day period of drying maintained after the disappearance of water on the field, which increased yield. However, from a regional or national perspective, this would be a sub-optimimal solution.

In Iraq as in many other water-constrained countries or regions, water for irrigation is more of a constraint than land area. Thus, decision-making at national level should be guided by the productivity of water rather than by the yield per hectare of land. Khidhir’s analysis showed that with SRI methods and a longer interval between water deliveries, the area under irrigated rice production could be about tripled under SRI with only a 10-15% reduction in average yield. The country’s total irrigated rice area as well as production could be greatly increased by making a huge saving of water at the cost of a small decline in per-hectare yield.

Getting individual farmers to accept a somewhat lower yield per hectare would require some policy initiatives and economic incentives such as giving subsidies or making deficiency payments. However, the national benefit from using SRI with more water-sparing irrigation would be immense.[57] Khidhir’s research informed the SRI community about the need to think beyond the individual farmer and the individual field. Decision-makers also should be thinking about the productivity of water rather than just about the productivity of land when water is scarce and a constraint on total production. SRI methods can make the trade-off more beneficial for both farmers and the country.



As seen already, the most knowledge about SRI coming from this region has come, not surprisingly, from Madagascar, largely at the initiative of Prof. Robert Randrimiharisoa. However, there has been some significant knowledge generation from other countries.

The Gambia

The first SRI research done outside of Madagascar was by Mustapha Ceesay, a former director of this country’s agricultural experiment station at Sapu. Mustapha happened to be doing a master’s degree at Cornell in crop and soil science when we in CIIFAD concluded that SRI is ‘for real’ and warranted evaluation outside Madagascar. On his own, Mustapha undertook to do SRI trials back at the Sapu research station when he returned to his home country during the summer of 2001.[58]

For his PhD thesis research, Mustapha subsequently evaluated SRI methods as well as the new NERICA rice varieties that were being disseminated by the Africa Rice Center, WARDA. Although he did not make much of this conclusion in his thesis, because it could cause a lot of controversy, Mustapha found that SRI methods could bring more and more cost-effective benefits for Gambian farmers than did the new varieties, some important learning.[59] Mustapha’s first SRI trial plots at the Sapu station are shown below, along with him standing in the middle of an SRI plot at harvest time.

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This was the next locus for research on SRI in Africa after Erika Styger moved here in 2007, working with the NGO Africare while doing also independent consulting. Her and others’ work in Mali is considered in Chapter 44, but it is important to note here is that the farmer-participatory trials which she set up in the Timbuktu region to evaluate SRI methods there showed that the methods with some adaptation could succeed under the harsh conditions on the edge of the Sahara Desert.[60] These trials focused first on rice, but a farmer initiative with wheat (SWI) the next year further developed our confidence that SRI methods were widely adaptable to diverse agroecosystems and able to improve crops beyond rice (Chapter 12).


Bancy Mati at the Jomo Kenyatta University of Agriculture and Technology learned about SRI when we fortuitously met in January 2009 at the coffee shop in the atrium of FAO in Rome.[61] In addition to being a productive researcher, Bancy was a prodigious networker, linking university research with government and NGO allies and working directly with farmers, initially in the country’s largest irrigation scheme at Mwea. She also had a very mature and self-directed PhD student, Jackline Ndiiri, who did her thesis research on SRI. Bancy and students and colleagues together studied and published on what SRI methods could accomplish under Kenyan conditions (Chapter 45).

One area of knowledge where the group assembled by Bancy broke some important new ground concerned the impact that SRI crop and water management could have on human health. It was reasonable to suspect that stopping the continuous flooding of paddy fields could slow or prevent the spread of mosquito-borne diseases, particularly malaria but also maladies like dengue fever and Japanese encephalitis.

Master’s thesis research by Kepha Omwenga found that within 2 days of draining rice fields in the Mwea scheme, the emergence of adult mosquitoes from larva was reduced by 98%.[62] This indicated another way in which SRI practices could benefit rural communities over and above those documented by other researchers regarding increased yield, seed saving, water saving, etc. summarized in Chapter 1.


The first person to try SRI methods in this country was Pascal Gbenou, who in addition to operating his own farm operated a school and demonstration site for integrated sustainable agriculture, called SAIN (Solidarité Agricole Integrée) at Kakanitchoé.  He was also the founder and first president of the Consultative Council of Rice Farmers in Benin.

When he started a PhD program at the national university (Université d’Abomey), Pascal worked with the national rice farmers’ association that he had helped establish to lay out a plan and methodology for participatory evaluation of the new methods in two contrasting agroecosystems along the Ouémé River in central Benin. One area of trials was in lowland floodplains, and the other area was more upland, on a plateau above the river.

A planning group of 90 farmers from all of the rice-growing regions of the country worked out the research design with Gbenou’s guidance, comparing their usual methods with recommended SRI methods. They also formulated a farmer-determined intermediate system for rice cultivation in between, much as in the farmer-participatory research that evaluated SRI in upland areas of Southeast Asia (Chapter 7).

Trials were conducted on farmers’ fields in the two locations, lowland and upland. The 54 farmers who lived and worked in the Ouémé Valley were assisted by 36 farmers from other parts of Benin, who came to assist in managing the trials during land preparation, nursery establishment, transplanting, flowering, and harvesting.

The results from replicated trials conducted during two seasons in each location showed SRI to be preferable to the other two sets of practices in all respects. The SRI yield was 56% higher than the other practices while requiring 87% less seed, with crop maturation 14 days sooner on average. Although farmers’ labor inputs were 36% higher with SRI (farmers were just learning the methods), this was compensated for by 42% greater net economic returns with SRI. Also, farmers saw that the use of mechanical weeders made weed control with SRI easier and quicker.

One interesting part of the farmers’ research design was that it included also comparisons of 8-day vs. 12-day seedlings within the SRI methodology. Farmers saw the superiority of transplanting younger plants when these gave half a tonne more yield per hectare in the upland trials on the plateau, and almost 1 tonne more yield in the more-fertile flood plains.[63]

This kind of farmer participation in SRI evaluations was innovative and exemplary, much like the SRI Lower Mekong Basin project in four countries of Southeast Asia reported on in Chapter 8, which had a similar research design and similar results. That this was a farmer-managed evaluation that got published in a respectable scientific journal was also an accomplishment.




As noted in the previous chapter, there has not been much research done in this region yet to explain SRI effects, only to validate the methods. However, as reported in Chapter 5, there was instructive SRI research was done in this country by Marie-Soleil Turmel, a Canadian PhD student from McGill University attached to the Tropical Research Institute in Panama. Her work advanced our understanding of how the plant nutrient phosphorus, which plays a key role in soil fertility, is affected by SRI practices.[64]

Many of the ‘poor’ soils in developing countries are deficient in available phosphorus because of the long, slow process of soil weathering that leaches out P and other minerals and also makes the soils acidic. Adding inorganic nitrogen fertilizer to these soils increases their acidity, which in turn makes P less available. Adding inorganic phosphorus amendments to these soils has diminished effectiveness because the P in the amendments becomes quickly fixed in insoluble compounds and is thus unavailable for plant use.

Flooding paddy soils can neutralize their acidity to some extent, but this has the effect then of degrading roots and of inhibiting many beneficial soil biota, both microorganisms and macrofauna like earthworms. Populations of phosphorus-solubilizing organisms which include rhizobacteria and mycorrhizal fungi can be enhanced by active soil aeration through mechanical weeding and by increasing the supply of soil organic matter, thereby making ‘poor’ soils more fertile as seen from Turmel’s research, which is reported in Chapter 5.    

We expect that in the coming years, more researchers in Latin America and the Caribbean will be attracted to the study of SRI and its multiple causal mechanisms, respectively and collectively. At present, there is a strong preoccupation with plant breeding approaches to crop improvement, with genetic upgrading and modification having center stage. But with growing interest in epigenetics and with advances in our understanding of how to utilize genetic potentials more fully, the kinds of improvements in phenotype that SRI and other methods of management are eliciting should capture the attention of both high-tech and low-tech researchers and innovators. The relationship between phenotypes and genotypes is discussed in the next chapter.

*    *     *     *     *     *

A comprehensive review of all individual research efforts and findings would require several books. This chapter gives readers an idea of how in the years after Fr. Laulanié’s death, researchers around the world have expanded our understanding of SRI beyond his fertile and insightful work.

In the process, many adaptations have been made in SRI to suit a variety of climates and situations, while comprehension of how to provide rice plants with better growing environments has expanded. To conclude this chapter, we summarize below the findings reported above, to give an overview of the range and variety of contributions from researchers that have built up a global appreciation of SRI.

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[1] There have been no resources available for maintaining a complete inventory of SRI publications, but reasonably complete listings are given at:,, and

Access to publications can be facilitated by joining the SRI Research Network at no cost:

[2] This was manifested during a memorable drive in 2005 from Hangzhou, China with Zhu Defeng, volunteer national coordinator for our informal SRI network in China, to visit Bu Tou village in Tian Tai township, where the China National Rice Research Institute had started SRI trials and demonstrations; see report, pages 2-4.

     We got talking about Zhu’s experiences during the Cultural Revolution in China, between 1966 and 1976, when he had been a university student and was ‘sent down’ by Communist Party cadres to live and work (manually) in a poor village. While he regretted that he had to suspend his studies for several years during the convulsions of that disruptive period, he indicated no bitterness or unhappiness about this chapter in his life, commenting that it has been a good learning experience for him to get to know more about the life conditions of rural Chinese and about the qualities and skills of these people. From the way that he, a senior rice scientist, interacted with farmers in Bu Tou, it was evident the experience 30 years earlier had affected him greatly.

[3] Such as Ngo Tien Dung, at the time head of the Plant Protection Division of the Ministry of Agriculture and Rural Development in Vietnam; Rajendra Uprety in the Morang District Agricultural Development Office in Nepal; Shuichi Sato, technical assistance team leader for the Japanese consulting firm Nippon Koei in Indonesia; and Asif Sharif, executive of Pedaver Pvt. Co. Ltd. in Pakistan.

[4] At the time of writing, Cao was Vice-Governor of Jiangsu Province in China. He had done his PhD degree at Oregon State University, coincidentally on phyllochrons in wheat. This helped him understand quickly how SRI’s management and effects differed from conventional rice cultivation.

[5] Wang Shaohua, Cao Weixing, Jiang Dong, Dai Taibo and Zhu Yan, ‘Physiological characteristics and high-yield techniques with SRI rice,’ in Assessment of the System of Rice Intensification: Proceedings of an International Conference held in Sanya, China, April 1-4, 2002, 116-124 (2002).

[6] Zhu Defeng, Cheng Shihua, Zhang Yuping and Lin Xianqing, ‘Tillering patterns and the contribution of tillers to grain yield with hybrid rice and wide spacing,’ in Assessment of the System of Rice Intensification: Proceedings of an International Conference held in Sanya, China, April 1-4, 2002, 125-131 (2002).

[7] The CNRRI researchers did not evaluate the full set of SRI recommendations because they thought these would be too much of a departure from standard practice for widespread uptake by Chinese farmers. So, they tested the effects of SRI recommendations for reducing plant density and for more reliance on organic fertilization, using young seedlings and also halting the continuous flooding of rice paddies.

[8] Note that the lowest level of N application evaluated in these trials was well above the level of 80 kg per hectare that had been determined by some scientists to be optimal for rice production in China, as discussed in Chapter 6.

[9] X.Q. Lin, D.F. Zhu, H.Z. Chen, S.H. Cheng and N. Uphoff, ‘Effect of plant density and nitrogen fertilizer rates on grain yield and nitrogen uptake of hybrid rice (Oryza sativa L.),’ Journal of Agricultural Biotechnology and Sustainable Development, 1: 44-53 (2009). Recommended plant density for SRI would be 160,000 per hectare (25×25 cm spacing = 16 plants per m²).

[10] The figure here shows an average for all of the treatments, averaged for all levels of N application. The numbers reported in the text come from Table 2 of Lin et al. (2009).

[11] Such cooperation between university and research institute personnel is not common in China, but convergent interest in SRI was a kind of glue. Ms. Zhao published three additional articles from her research on SRI: L.M. Zhao, L.H. Wu, C.J. Dong and Y.S. Li, ‘Rice yield, nitrogen utilization and ammonia volatilization by modified rice cultivation at varying nitrogen rates,’ Agricultural Sciences, 1: 10-16 (2010); L.M. Zhao, L.H. Wu, Y.S. Li, S. Animesh, D.F. Zhu and N. Uphoff, ‘Comparison of yield, water use efficiency and soil microbial biomass as affected by the System of Rice Intensification,’ Communications in Soil Science and Plant Analysis, 41: 1-2 (2010); and L.M. Zhao, L.H. Wu, M.Y. Wu and Y.S. Li, ‘Nutrient uptake and water use efficiency as affected by modified rice cultivation methods with reduced irrigation,’ Paddy and Water Environment, 9:25-32 (2011). Unfortunately, after finishing her PhD, the only suitable academic position that Zhao was able to find was at Inner Mongolia Agricultural University, where rice is not an important crop. I supported her application for an Elsevier Foundation post-doctoral fellowship in 2011 to enable her to continue her work on SRI, but this was not successful.

[12] More is said about Prof. Yuan’s role in getting SRI started in China, in Chapters 21 and 37. His article about SRI published in 2001 in the journal Hybrid Rice, 16:1-3 (in Chinese) reporting on his own experience with SRI evaluation helped to attract the attention of Chinese rice researchers. He also made presentation on SRI in Sichuan province in 2001.

[13] This method was described by Prof. Yuan in his keynote address to the Sanya conference in 2002. See also M. Fan, S.H. Lu, R. Jiang, X. Liu and F.S. Zhang, ‘Triangular transplanting pattern and split nitrogen fertilizer application increase rice yield and nitrogen fertilizer recovery,’ Agronomy Journal, 101: 1421-1425 (2009).

[14] Zheng Jiaguo, Lu Xianjun, Jiang Xinlu and Tang Yonglu, ‘The system of rice intensification (SRI) for super high yields of rice in Sichuan Basis,’ poster at 4ᵗʰ International Crop Science Congress (2004). On other Sichuan research, see Zheng Jiaguo, Chi Zhongzhi, Li Xuyi and Jiang Xinlu, ‘Agricultural water savings possible through SRI for water management in Sichuan, China,’ Taiwan Water Conservancy, 61: 50-62 (2013).

[15] Data reported in 2013 reference the preceding endnote. Unfortunately, there are no comparably detailed data for Zhejiang province, but Zhu and Lin say that the expansion in their province was roughly the same.

[16] See listing of Chinese research on SRI-Rice web site. SRI-Rice has tried as best it could to keep track of Chinese SRI research, assisted by Chinese students studying at Cornell.

[17] Wei Wu, B. Ma and N. Uphoff, ‘A review of the system of rice intensification in China,’ Plant and Soil, 393:361-381 (2015).

[18] Phrek and I happened to be on an evaluation team together in 1999 for the Center for Integrated Agricultural Development at the China Agriculture University in Beijing. He picked up on the ideas of SRI quickly when I explained them and tried them out when he got back to his university.

[19] ‘Experience with the System of Rice Intensification in Northern Thailand,’ in Assessment of the System of Rice Intensification: Proceedings of an International Conference held in Sanya, China, April 1-4, 2002, 77-79 (2002). We subsequently learned that this was probably due to endemic populations of root-feeding nematodes in the soil that multiplied under aerobic soil conditions and impaired plants’ health and functioning. See endnote 24 in Chapter 8.

[20] The title for the research was: ‘Effects of different water regimes on soil nutrient status, microbial activity, and root development supporting increased rice production.’ The Asia Rice Foundation of USA supported this with a grant of $4600, thanks to support from Ronnie Coffman and Robert Herdt, trustees for the Foundation.

[21] A. Mishra, M. Whitten, J.W. Ketelaar and V.M. Salokhe, ‘The System of Rice Intensification (SRI): A challenge for science, and an opportunity for farmer empowerment towards sustainable agriculture,’ International Journal of Agricultural Sustainability 4: 193-212 (2006). This is summarized in the annex following Chapter 20.

[22] A. Mishra and V.M. Salokhe, ‘Seedling characteristics and early growth of transplanted rice under different water regimes,’ Experimental Agriculture 44: 1-19 (2008); A. Mishra and V.M. Salokhe, ‘The effects of planting pattern and water regime on root morphology, physiology and grain yield of rice,’ Journal of Agronomy and Soil Science 196: 368-378 (2010); A. Mishra and N. Uphoff, ‘Morphological and physiological responses of rice roots and shoots to varying water regimes and  soil microbial densities,’ Archives of Agronomy and Soil Science 59: 705-731 (2012).

[23] Dr. Vo Tong Xuan, a rice specialist with long and close ties to IRRI, was on the same evaluation team in China described in endnote 18 above. Upon returning to Vietnam, he set up some SRI trials at his university (Can Tho) in the Mekong Delta and found no yield enhancement. Possibly this was because it is difficult to make and keep the low-lying delta soils there aerobic because of so much seasonal flooding.

[24] ‘SRI Application in Rice Production in Northern Ecological Areas of Vietnam (updated through 2006)’ posted on SRI-Rice website.

[25] ‘Acknowledging “The Application of the System of Rice Intensification in a number of Northern Provinces” to be a technical advance,’ Decision No. 3062/QD/BNN-KHCN, Ministry of Agricultural and Rural Development, Hanoi, October 15, 2007.

[26] ‘Over 1 million Vietnamese farmers benefit from SRI,’ People’s Army Newspaper Online, October 18, 2011, Ministry of National Defense.

[27] While doing a master’s degree in Agricultural Systems at the Multiple Cropping Center of Chiangmai University in northern Thailand, Phu was a close friend of Klaus Prinz, a German expatriate working with the McKean Rehabilitation Center there, who was assisting with the initial SRI trials done at that university. In 2003, Klaus sent an email to Phu telling him about SRI. Phu was interested in ecological agriculture and SRI from his master’s course in Thailand and also his PhD studies at the University of the Philippines at Los Baños with his advisors Teodoro Mendoza and Pamela Fernandez.

     When Phu began his work at Thai Nguyen University in the spring season of 2004, he started on-campus SRI trials. Then he did successful SRI demonstrations in nearby mountain villages in the northern parts of Vietnam.  The results of his research and application were presented mostly in Vietnamese publications, so they did not have impact outside the country. When a national Vietnam SRI network was formed, Phu became its coordinator. On Phu’s initial SRI work, see my 2006 trip report, pages 8-13.

[28] J-SRI maintains a website for national and international communication.

[29] T. Horie, T. Shiraiwa, K. Homma, K. Katsura, S. Maeda and H. Yoshida, ‘Can yields of lowland rice resume the increases that they showed in the 1980s?’ Plant Production Science, 8: 257–272 (2005). When I met Prof. Horie at the 2ⁿᵈ International Rice Congress in New Delhi in 2006, we discussed the critique of SRI that Achim Dobermann had made based on rice crop growth modeling  in his article, ‘A critical assessment of the system of rice intensification (SRI),’ Agricultural Systems, 79: 261-281 (2004). Horie said that this critique should not be taken very seriously because he had himself helped to develop the computer model that Dobermann had used for the critique, and he knew its many limitations.

[30] Y. Tsujimoto, T. Horie, H. Randriamihary, T. Shiraiwa and K. Homma, ‘Soil management: The key factors for higher productivity in the fields utilizing the system of rice intensification (SRI) in the central highlands of Madagascar,’ Agricultural Systems, 100: 61-71 (2009). Tsujimoto measured yields of up to 9.9 tonnes per hectare on SRI-managed soils that received no mineral fertilizer, only organic material, but no yields that matched the 21-tonne yield discussed in the next chapter.

[31] T. Chapagain and E. Yamaji, ‘The effects of irrigation method, age of seedling, and spacing on crop performance, productivity and water-wise rice production in Japan,’ Paddy and Water Environment, 8: 81-90 (2010); T. Chapagain, A. Reisman and E. Yamaji, ‘Assessment of System of Rice Intensification (SRI) and conventional practices under organic and inorganic management,’ Rice Science, 18: 311-320 (2011). In the SRI-managed plots, lodging was 10%, and all of this partial, while in the conventionally-managed plots, lodging was 55%, 47% of which was total, not partial.

[32] ‘Methane and Nitrous Oxide Emissions from Paddy Rice Fields in Indonesia,’ powerpoint presentation by Dr. Kimura Dorothea, Tokyo University of Agriculture and Technology (2008).

[33] J.D. Choi, G.B. Kim, W.J. Park M.H. Shin, Y.H. Choi, S. Lee, S.J. Kim and D.K. Yun, ‘Effect of SRI water management on water quality and greenhouse gas emissions in Korea,’ Irrigation and Drainage, 63: 263-270 (2014).

[34] J.D. Choi, G.Y. Kim, W.J. Park, M.H. Shin, Y.H. Choi, S. Lee, D.B. Lee and D.K. Yun, ‘Effect of SRI methods on water use, NPS pollution discharge, and GHG emission in Korean trials,’ Paddy and Water Environment, 13: 205-213 (2015).

[35] Prof. Yu-chuan Chang at Hsing Wu University has taken the lead in adapting SRI ideas to Taiwan’s physical and socio-economic conditions and in establishing an SRI network there. Y.C Chang, N. Uphoff and E. Yamaji, ‘A conceptual framework for eco-friendly paddy farming in Taiwan, based on experimentation with system of rice intensification (SRI) methodology,’ Paddy and Water Environment, 14: 169-183 (2015).

     Trials re-validated and adapted SRI practices for Taiwanese conditions. The principle of single seedlings was clearly supported. For example, single seedlings gave a yield of 11.4 tonnes per hectare in replicated trials, while 2 seedlings per hill, other conditions being the same, produced 9.5 tonnes per hectare; and 3 seedlings per hill yielded 9.1 tonnes. The main adaptations necessary are to find ways to reduce SRI’s labor requirements as agricultural labor is very limited in Taiwan.

[36] When Iswandi Anas and Shuichi Sato started organizing the Indonesian national network in 2008, they decided to call it Ina-SRI in order to preserve the acronym ‘I-SRI’ for an international network for SRI.

[37] An example would be N.A.I. Hasanah, B.I. Setiawan, M. Mizuguchi, C. Arif, G.R. Sands and S. Widodo, ‘Triangle graphs development for estimating methane and nitrous oxide gases emission for the system of rice intensification (SRI),’ Journal of Environmental Science and Technology, 10:206-214 (2017).

[38] In a poster presented at the 4ᵗʰ International Rice Congress in Bangkok (2014), Iswandi and three of his IPB students reported from replicated trials that whereas the first SRI crop had a 27% yield advantage over conventionally-managed cropping (6.65 vs. 5.23 tonnes per hectare), in the following ratoon crop there was an SRI advantage of 38% (4.59 vs. 3.32 tonnes). 

[39] B.I. Setiawan, A. Irmansyah, C. Arif, T. Watanabe, M. Mizoguchi and J.H. Kato, ‘Effects of groundwater level on CH₄ and N₂O emissions under SRI paddy management in Indonesia,’ Taiwan Water Conservancy, 61: 135-146 (2013); C. Arif, B.I. Setiawan and M. Mizoguchi, ‘Determining optimal soil moisture for system of rice intensification paddy field using genetic algorithms,’ Jurnal Irigasi, 9: 29-40 (2014)

[40] S. Sato and N. Uphoff, ‘A review of on-farm evaluations of system of rice intensification methods in Eastern Indonesia,’ CAB Reviews, 2:54 (2007); and S. Sato, E. Yamaji and T. Kuroda, ‘Strategies and engineering adaptions to disseminate SRI methods in large-scale irrigation systems in Eastern Indonesia,’ Paddy and Water Environment, 9: 79-88 (2011).

[41] Together with a government IPM extension worker, Alik Sutaryat, Sato formed an NGO, Aliksa, to promote organic SRI cultivation. This evolved into the Nagrak Organic SRI Center, funded and managed by a progressive businessman, Ahmed Jatika, as discussed in Chapter 34. This is mentioned to highlight the kind of inter-sectoral collaboration that underlay SRI activities especially in Indonesia.

[42] Local research is reported on in ‘Report on a Visit to Cambodia to Review SRI Progress, July 14-18, 2007,’ pages 14-20.

[43] R.P. Lando and S. Mak, Deepwater Rice in Cambodia: A Baseline Survey, IRRI Research Paper No. 153, International Rice Research Institute, Manila, Philippines (1994).

[44] D. E. Mulu, ‘Effects of seedling age, spacing and season on phyllochrons, yield and yield components of rice using the principles of the System of Rice Intensification,’ PhD thesis, University of the Philippines at Los Baños (2004).

[45] See listing of publications on SRI by Malaysian researchers posted by SRI-Mas.

[46] F. Doni, C.R.C.M. Zain, A. Isahak, N. Sulaiman, F. Fathurrahman, N. Uphoff and W.M.W. Yusoff , ‘Relationships observed between Trichoderma inoculation and characteristics of rice grown under system of rice intensification (SRI) vs. conventional methods of cultivation,’ Symbiosis, 72:45–59 (2017); F. Doni, C.R.C.M. Zain, A. Isahak, F. Fathurrahman, A. Anhar, W.N.W. Mohamad, W.M.W. Yusoff and N. Uphoff,  ‘A simple, efficient, and farmer-friendly Trichoderma-based biofertilizer evaluated with the SRI rice management system,’ Organic Agriculture, 7: 1-17 (2017); F. Doni, M.S. Mispan,  N.S.M Suhaimi, N. Ishak and N. Uphoff, ‘Roles of microbes in supporting sustainable rice production using the system of rice intensification,’ Applied Microbiology and Biotechnology, 103: 5131-5142 (2019); and F. Doni, C.R.C.M. Zain, A. Isahak, F. Fathurrahman, A. Anhar, W.M.W. Yusoff and N. Uphoff, ‘Synergistic effects of System of Rice Intensification (SRI) management and Trichoderma asperellum SL2 increase the resistance of rice plants (Oryza sativa L.) against sheath blight (Rhizoctonia solani) infection,’ ms. under review.

[47] J.E. Sheehy, S.B. Peng, A. Dobermann, P.L. Mitchell, A. Ferrer, J.C. Yang, Y.B. Zou, X.H. Zhong and J.L. Huang, ‘Fantastic yields in the system of rice intensification: Fact or fallacy? Field Crops Research, 88: 1-8 (2004). This article, accepted and published within five weeks of its submission, is discussed in Chapter 28.

[48] A.K. Thakur, N. Uphoff and E. Antony, ‘An assessment of physiological effects of the System of Rice Intensification (SRI) compared with recommended rice cultivation practices in India,’ Experimental Agriculture, 46: 77-98 (2010).

[49] IARI staff who have published the most research on SRI include Anchal Dass, Radha Prasanna and Y.S. Shivay. In the IARI water management division, A.K. Choudhury and A.K. Singh have evaluated SRI effects. IARI also conducted the first published research on SWI, as discussed in Chapter 14.

[50] See Shambu’s first publication, SRI in India: Innovation History and Institutional Challenges, WWF-ICRISAT Program, Patancheru (2006); Shambu also took initiative to establish in his state a ‘learning alliance’ on SRI among NGO, university and government personnel. C.S. Prasad, K. Beumer and D. Mohanty, Towards a Learning Alliance: SRI in Orissa, WWF-ICRISAT Program, Patancheru (2007).

[51] Rajeev Rajbhandari  (2007) studied the effects of different plant densities and applications of N fertilizer. Sharad Pandey (2009) studied the effects of different weed management practices with SRI: hand weeding, mechanical weeding, and herbicides. Keshav Karki (2010) studied planting patterns and age of seedlings. Krishna Dhital (2011) compared SRI with farmer practice and direct-seeding, looking particularly at phenological differences, the timing of different stages of development. After completing his thesis, Rajeev and his fiancée Janani Thapa requested and were given a small grant from CIIFAD to  cover costs (no salary) of carrying out further extension work for SRI in the Chitwan Valley where both had done field studies, and where farmer interest in SRI had been sparked. Janani subsequently came to Cornell and completed an MPA degree, accompanied by Rajeev. Thereafter she did a PhD in Texas, eventually getting a faculty appointment at the University of Georgia.

[52] This information and following table are from Dhital’s MS thesis that was cited in the preceding endnote.

[53]  Forum for Youth Awareness and Activity, FAYA.  Khadka’s work in western Nepal was shown in the Flooded Cellar Production video made in 2013.

[54] With SRI management, a landrace (Thapachini) gave a yield of 8.11 t/ha, which was 91% higher than it yielded with farmers’ usual cultivation methods. Under SRI management, a high-yielding variety (Khumal-4) with which the local variety was being compared yielded 25% more than the Nepal Agricultural Research Council had advertised as its yield under optimal conditions. R.B. Khadka, H.P. Acharya and N. Uphoff, Performance of landraces and improved varieties under the System of Rice Intensification in Bhajang district of Nepal, Journal of Agriculture and Environment, 15: 1-10 (2014).

[55] R.B.  Khadka and N. Uphoff, ‘Effects of Trichoderma seedling treatment with System of Rice Intensification management and conventional transplanting of rice,’ Peer Journal, 7:e5877 (2019).

[56] As so often in the SRI story, Khidhir’s involvement with SRI was by happenstance. The two of us happened to meet in 2004 at an international conference on hybrid rice held in China, to which we had been invited by Prof. Yuan Longping. Given Khidhir’s interest particularly in water-saving, a great concern in water-short Iraq, as soon as he heard about SRI, he wanted to evaluate its performance in his country.

[57] K.A. Hameed, F.A. Jaber and A.J. Mosa, ‘Irrigation water use efficiency for rice production in Southern Iraq under System of Rice Intensification (SRI) management,’ Taiwan Water Conservancy, 61: 86-93 (2013); also K.A. Hameed, A.J. Mosa and F.A. Jaher, ‘Irrigation water reduction using System of Rice Intensification compared with conventional cultivation methods in Iraq,’ Paddy and Water Environment, 9: 121-127 (2011).

[58] M. Ceesay, ‘Experiments with the System of Rice Intensification in The Gambia,’ in Assessment of the System of Rice Intensification, Proceedings of an International Conference held in Sanya, China, April 1-4, 2002, 56-57 (2002). As I was finishing this chapter, Mustapha sent an email informing us that he had been appointed as FAO’s assistant country representative for The Gambia and as director for the FAO program there.

[59] The trials set up with farmers on fields near the station showed a tripling of yield: 7.4 tonnes per hectare with SRI vs. 2.5 tonnes with usual methods. Ceesay’s PhD thesis was completed in 2004.

     Results are summarized in M. Ceesay, W.S. Reid, E.C.M. Fernandes and N. Uphoff, ‘The effects of repeated soil wetting and drying on lowland rice yield with System of Rice Intensification (SRI) methods,’ International Journal of Agricultural Sustainability, 4: 5-14 (2006).

[60] E. Styger, G. Aboubacrine, M.A. Attaher and N. Uphoff, ‘The System of Rice Intensification (SRI) as a sustainable agricultural innovation: Introducing, adapting and scaling up SRI practices in the Timbuktu region of Mali,’ International Journal of Agricultural Sustainability, 9: 67-75 (2011); E. Styger, M.A. Attaher, H. Guindo, H. Ibrahim, M. Diaty, I. Abba and M. Traoré, ‘Application of system of rice intensification practices in the arid environment of the Timbuktu region in  Mali,’ Paddy and Water Environment, 9: 137-144 (2011).

[61] In January 2009, Willem Stoop, Mei Xie (World Bank Institute) and I were invited by the International Fund for Agricultural Development to make presentations on SRI to IFAD staff in Rome. During a coffee break, Bancy and I happened to meet and to start talking. As she was the director of her university’s Water Research and Resource Center, making more productive use of water in agricultural production was one of her major interests, which made SRI ideas attractive.

[62] K.G. Omwenga, J. Mwangangi, P.G. Home and B.M. Mati, Assessment of the Impact of the System of Rice Intensification (SRI) on Mosquito Survival at Mwea Rice Irrigation Scheme, Kenya, Master’s thesis, Jomo Kenyatta University of Agriculture and Technology, Nairobi (2014).

[63] P. Gbenou, A.M. Mitchell, A.B. Sedami and P.R. Agossou, ‘Farmer evaluations of the System of Rice Intensification (SRI) compared with conventional rice production in Benin,’ European Scientific Journal, 12: 30 (2016).

[64] M.S. Turmel, B.L. Turner and J.K. Whalen, ‘Soil fertility and yield response to the System of Rice Intensification,’ Journal of Renewable Agriculture and Food Systems, 26: 185-192 (2011); and M.S. Turmel, J. Espinosa, L. Franco, C. Pérez, H. Hernández, C. Rojas, D. Sánchez, N. Fernández, M. Barrios, J.K. Whalen and B.L. Turner, ‘On-farm evaluation of a low-input rice production system in China,’ Paddy and Water Environment, 9: 155-161 (2011).


PICTURE CREDITS: Norman Uphoff (Cornell); Zheng Jiaguo (SAAS); Mustafa Ceesay (Gambia)

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