The System of Rice Intensification (SRI): Understanding How and Why It Raises Productivity
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The document summarizes the System of Rice Intensification (SRI), a methodology developed in Madagascar to increase rice productivity through changes in plant management practices. SRI involves transplanting young seedlings singly and wider spaced, with minimal flooding. This induces greater root growth and soil biological activity, resulting in more tillers, larger plants and roots, higher yields, and other benefits. Field trials in many countries found SRI yields 30-100% higher than conventional methods with less inputs, water, and sometimes higher profits for farmers. The methodology is still evolving and many questions remain, but offers opportunities to improve rice and possibly other crop production systems.
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The System of Rice Intensification (SRI): Understanding How and Why It Raises Productivity
- 1. The System of Rice Intensification (SRI): Understanding How and Why It Raises Productivity Norman Uphoff, CIIFAD Cornell University, USA
- 3. Fr. Henri de Laulanié, SJ
- 4. Sebastien Rafaralahy and Justin Rabenandrasana
- 5. SRI In Brief : SRI is a methodology for getting more productive PHENOTYPES from existing GENOTYPES of rice by changing the management of plants, soil, water, and nutrients to (a) induce greater ROOT growth and (b) nurture more abundant and diverse SOIL BIOLOGICAL populations
- 6. Plant Physical Structure and Light Intensity Distribution at Heading Stage (CNRRI Research --Tao et al. 2002)
- 7. Single Cambodian rice plant transplanted at 10 days
- 16. SRI field in Sri Lanka -- yield of 13 t/ha with panicles having 400+ grains
- 18. CFA Camilo Cienfuegos, Cuba 14 t/ha -- Variety Los Palacios 9
- 19. Two rice fields in Sri Lanka -- same variety, same irrigation system, and same drought : conventional methods (left), SRI (right)
- 22. SRI IDEAS CAN BE EXTENDED TO UPLAND PRODUCTION Results of trials (N=20) by Philippine NGO, Broader Initiatives for Negros Development, with Azucena local variety ( 4,000 m 2 area ) -- using mulch as main innovation, not young plants
- 25. Cuba -- Variety 2084 (Bollito) -- 52 DAP
- 26. Dry Matter Distribution of Roots in SRI and Conventionally-Grown Plants at Heading Stage (CNRRI research: Tao et al. 2002) Root dry weight (g)
- 27. Root Oxygenation Ability with SRI vs. Conventionally-Grown Rice Research done at Nanjing Agricultural University, Wuxianggeng 9 variety (Wang et al. 2002)
- 28. SRI farmer in Cambodia
- 29. SRI farmer in Cuba -- 14 t/ha
- 36. Seeder Developed in Cuba
- 38. Effects of SRI vs. Conventional Practices Comparing Varietal and Soil Differences
- 42. Spread of SRI in Asia
- 51. .
Editor's Notes
- Prepared with information available as of February 1, 2003. These slides can be used or adapted, even translated, however SRI colleagues would be useful for explaining this methodology to others.
- Prepared with information available as of February 1, 2003. These slides can be used or adapted, even translated, however SRI colleagues would be useful for explaining this methodology to others.
- This figure is from research from the China National Rice Research Institute reported at the Sanya conference in April 2002 and published in the Proceedings. Two different rice varieties were used with SRI and conventional (CK) methods. The second responded more positively to the methods in terms of leaf area and dry matter as measured at different elevations, but there was a very obvious difference in the phenotypes produced from the first variety's genome by changing cultivation methods from conventional to SRI.
- This picture was contributed from Cambodia by Koma Yang Saing (CEDAC). Viewers should try to imagine the very small single young seedling from which this massive plant grew.
- This was one of the first data sets that began laying a scientific foundation for SRI. Data were gathered from 76 farmers around Ambatovaky, a town on the western side of the peripheral zone around Ranomafana National Park in Madagascar, during the 1996-97 season. We had confidence in the field worker who collected the data, Simon Pierre, who had worked with Fr. de Laulanie before his death. The correlation between number of tillers per plant and number of grains per panicle was +.65, rather than the negative one expected from the literature. We have seen this positive relationship many times since this first analysis was done.
- This helps to explain our problem of "the agronomists' $100 bill." SRI is quite "counterintuitive." Indeed, it even sounds crazy. But we have experience and evidence that this "less is more" dynamic operates, and subsequent slides provide a number of scientific explanations for why fewer or smaller inpouts produce more in the case of irrigated rice
- Bruce Ewart, ADRA representative in Indonesia, got 7 farmers in West Timor to try SRI methods in 2002, with the encouragement of Roland Bunch. These are better farmers than their peers, as seen from their yield that season with current methods (4.4 t/ha), more than double the usual yield in the area. Their SRI plots averaged 11.7. Farmers working with ADRA in Lampung, Sumatra, got 8.5 t/ha with SRI methods compared to their usual production of 3 t/ha. Pablo Best reported that when farmers in Pucallpa, a lowland jungle area, tried SRI, they got a yield of 8 t/ha, four times their previous average, and not needing to do 8-10 hours/day of bird scaring at the end of the season because with SRI, the heavy panicles hung downward (but not lodging) so that birds could not get to them. Instead of letting cattle graze on the regrowth after harvest, the rice was allowed to produce a second (ratoon) crop, which was 5.5 t/ha, 70% of the first. Controlled trials in Benin, having read the account of SRI in ECHO Development Notes, found about a 5-fold difference in yield between SRI and conventional practice. The Agricultural Training Institute in the Philippines tried SRI methods with three varieties in Cotabato, Mindanao, and got an average yield of 12 t/ha, three times the usual yield in that area. The economic return averaged 290% as the value of rice produced was almost four times the cost of production.
- Bruce Ewart, ADRA representative in Indonesia, got 7 farmers in West Timor to try SRI methods in 2002, with the encouragement of Roland Bunch. These are better farmers than their peers, as seen from their yield that season with current methods (4.4 t/ha), more than double the usual yield in the area. Their SRI plots averaged 11.7. Farmers working with ADRA in Lampung, Sumatra, got 8.5 t/ha with SRI methods compared to their usual production of 3 t/ha. Pablo Best reported that when farmers in Pucallpa, a lowland jungle area, tried SRI, they got a yield of 8 t/ha, four times their previous average, and not needing to do 8-10 hours/day of bird scaring at the end of the season because with SRI, the heavy panicles hung downward (but not lodging) so that birds could not get to them. Instead of letting cattle graze on the regrowth after harvest, the rice was allowed to produce a second (ratoon) crop, which was 5.5 t/ha, 70% of the first. Controlled trials in Benin, having read the account of SRI in ECHO Development Notes, found about a 5-fold difference in yield between SRI and conventional practice. The Agricultural Training Institute in the Philippines tried SRI methods with three varieties in Cotabato, Mindanao, and got an average yield of 12 t/ha, three times the usual yield in that area. The economic return averaged 290% as the value of rice produced was almost four times the cost of production.
- Picture provided by Gamini Batuwitage, Sri Lanka, of field that yielded 17 t/ha in 2000.
- This picture from Sri Lanka shows two fields having the same soil, climate and irrigation access, during a drought period. On the left, the rice grown with conventional practices, with continuous flooding from the time of transplanting, has a shallower root system that cannot withstand water stress. On the right, SRI rice receiving less water during its growth has deeper rooting, and thus it can continue to thrive during the drought. Farmers in Sri Lanka are coming to accept SRI in part because it reduces their risk of crop failure during drought.
- Dr. Janaiah visited Sri Lanka the last week of October, 2002, and talked with 30 farmers in four villages who had been practicing SRI and who could give him detailed data. He had previously done such an evaluation for IRRI of the costs and benefits of adopting hybrid rice, having been on the IRRI staff in Los Banos from 1999 to 2002. He found SRI to be a much more profitable innovation for rice production than adoption of hybrids. We have found that SRI methods give the highest yields with hybrid varieties so there is not necessary contradiction or competition between the two. The SRI results reported from the Philippines, by the Agricultural Training Institute of the Department of Agriculture, from trials with three varieties at its Cotobato center in Mindanao (slide 20), calculated that the cost of production per hectare was 25,000 pesos, while the value of the rice yield with SRI was 96,000 pesos, a return of almost four times. Thus there are other evaluations of net profit from SRI that are even more favorable than Janaiah's calculation.
- The "economist's $100 bill" refers to the joke about an economist and his friend who were walking together down the street one day when the friend saw a $100 bill on the sidewalk. Thinking that his friend, being concerned with money, would surely pick the bill up, he did not reach down himself. But the economist walked right by. The friend asked, didn't you see that $100 bill on the sidewalk? Why didn't you pick it up? The economist replied,It wasn't a real $100 bill. If it had been genuine, since people are rational, someone would have picked it up by now, so I am sure that it was a counterfeit, and I didn't want to waste any effort on it. Agronomists have regarded SRI with similar skepticism, dismissing it by saying if it were indeed as good as reported, it should have been discovered previously, given the many millions of farmers and thousands of scientists who have worked with rice. So, therefore, SRI must not be genuine. SRI contradicts a number of key concepts held by agronomists and economists, giving them reasons to reject it, without giving it an empirical evaluation. However, the evidence in support of SRI is mounting year by year, month by month.
- The "economist's $100 bill" refers to the joke about an economist and his friend who were walking together down the street one day when the friend saw a $100 bill on the sidewalk. Thinking that his friend, being concerned with money, would surely pick the bill up, he did not reach down himself. But the economist walked right by. The friend asked, didn't you see that $100 bill on the sidewalk? Why didn't you pick it up? The economist replied,It wasn't a real $100 bill. If it had been genuine, since people are rational, someone would have picked it up by now, so I am sure that it was a counterfeit, and I didn't want to waste any effort on it. Agronomists have regarded SRI with similar skepticism, dismissing it by saying if it were indeed as good as reported, it should have been discovered previously, given the many millions of farmers and thousands of scientists who have worked with rice. So, therefore, SRI must not be genuine. SRI contradicts a number of key concepts held by agronomists and economists, giving them reasons to reject it, without giving it an empirical evaluation. However, the evidence in support of SRI is mounting year by year, month by month.
- This is a figure also from research reported by the China National Rice Research Institute to the Sanya conference and published in its proceedings. It shows how the roots of the same variety (two varieties shown) grow deeper into the soil with SRI methods compared to conventional ones (CK).
- This figure from report by Nanjing Agricultural University researchers to the Sanya conference, and reproduced from those proceedings, shows that the oxygenation ability of rice roots growing under SRI conditions are about double the ability, throughout the growth cycle, compared to the same variety grown under conventional conditions.
- This picture was provided by Koma Yang Saing (CEDAC) of a pleased Cambodian farmer, showing the size of a massive root ball with a SRI rice plant.
- These are just the most obvious contributions. Our understanding of this netherworld is limited, though fortunately there are a growing number of microbiologists using very advanced modern techniques, such as DNA analysis, to map and track what is going on in the soil. The discussion that follows is can be viewed as introductory or superficial, or both.
- Most people know that leguminous plants "fix" N in their roots through nodules on the roots inhabited by certain bacteria, rhizobia. And by implication, most thinks that non-leguminous plants "do not fix nitrogen." This is correct in terms of locus, but it misleads. All of the gramineae species (rice, wheat, sugar cane, etc.) have free-living bacteria in their root zones (referred to as 'associated' microbes) that fix N. Even in fertilized crops, a majority of the N taken up by the roots is from organic sources. And there is evidence that adding inorganic N to the root zone inhibits or suppresses the roots' and microbes' production of nitrogenase, the enzyme needed to fix N. So there is a tradeoff, in that adding inorganic N fertilizer reduces the N that is produced by natural biological processes. Or most relevance to SRI is research published more than 30 years ago reporting that when aerobic and anaerobic horizons of soil are mixed, BNF increases greatly compared to that originating from either aerobic or anaerobic soil. This suggests that the water management and weeding practices of SRI could be actively promoting N production in the soil. We have no research results to support this inference (though see data in Slide 49), but the yield increases with SRI practices require large amounts of N. BNF is the most plausible explanation.
- These data from a study done by Fide Raobelison under the supervision of Prof. Robert Randriamiharisoa at Beforona station in Madagascar, and reported in Prof. Robert's paper in the Sanya conference proceedings, give the first direct evidence to support our thinking about the contribution of soil microbes to the super-yields achieved with SRI methods. The bacterium Azospirillum was studied as an "indicator species" presumably reflecting overall levels of microbial populations and activity in and around the plant roots. Somewhat surprisingly, there was no significant difference in Azospirillum populations in the rhizosphere. But there were huge differences in the counts of Azospirillum in the roots themselves according to soil types (clay vs. loam) and cultivation practices (traditional vs. SRI) and nutrient amendments (none vs. NPK vs. compost). NPK amendments with SRI produce very good results, a yield on clay soil five times higher than traditional methods with no amendments. But compost used with SRI gives a six times higher yield. The NPK increases Azospirillum (and other) populations, but most/much of the N that produced a 9 t/ha yield is coming from inorganic sources compared to the higher 10.5 t/ha yield with compost that depends entirely on organic N. On poorer soil, SRI methods do not have much effect, but when enriched with compost, even this poor soil can give a huge increase in production, attributable to the largest of the increases in microbial activity in the roots. At least, this is how we interpret these findings. Similar research should be repeated many times, with different soils, varieties and climates. We consider these findings significant because they mirror results we have seen in other carefully measured SRI results such as the Anjomakely factorial trials (Slide 24) and the previous season's trials with SRI at Beforona (10.2 t/ha).
- Here we look just at the effect of young seedlings, on better and poorer soil, at Anjomakely. The synergistic effect of compost with aerated soil is seen in the bottom three lines. Compost with saturated soil does less well (7.7 t/ha) than NPK with aerated soil (8.77 t/ha), but compost with aerated soil does by far the best (10.35 t/ha) on better soil. The same relationship is seen on poorer soil (right-hand column).
- Here we look just at the effect of young seedlings, on better and poorer soil, at Anjomakely. The synergistic effect of compost with aerated soil is seen in the bottom three lines. Compost with saturated soil does less well (7.7 t/ha) than NPK with aerated soil (8.77 t/ha), but compost with aerated soil does by far the best (10.35 t/ha) on better soil. The same relationship is seen on poorer soil (right-hand column).
- Summary results from two sets of factorial trials in two different agroecological settings in 2000 and 2001 by honors students in the Faculty of Agriculture at the University of Antananarivo. The first setting was on the west coast of Madagascar, at an agricultural experiment center near Morondava, with a tropical climate, near sea level, and poor sandy soil. (This location was chosen because there are few pest or disease problems during that season which could affect plant performance.) The second was on the high plateau near the village of Anjomakely, 18 km south of Antananarivo, with a temperate climate, about 1200 m elevation, and better soils, comparing results on better clay soil and poorer loam soil. In 2000, Jean de Dieu Rajonarison did trials on 288 plots (2.5x2.5 m) at the Centre de Baobab, with sandy soil [ sable roux], evaluating the effects of five factors: variety – HYV [2798] vs. traditional [riz rouge]; age of seedling [16-day vs. 8-day], seedlings per hill [3 vs. 1], water management [continuous flooding vs. water control, with deliberate aeration of the soil during the vegetative growth period], and nutrient amendments [none vs. NPK vs. compost]. The study was designed with spacing as a sixth factor [25x25 vs. 30x30cm], sok that there were 96 combinations (2x2x2x3x2x2), with three replications. But both spacings were within the SRI range, and the average yield distinguished by spacing [each N = 144] was identical, 3.18 t/ha. So the analysis deals with only five factors, having six replications for each average reported. Plots were randomly distributed according to a modified Fisher bloc design, except for water management, for which the plot with these two different treatments had to be separate to avoid effects of lateral seepage. In 2000, Andry Andriankaja did trials on 240 plots (2.5x2.5m) on a farmer’s fields near Anjomakely, using a traditional rice variety [ riz rouge], evaluating the effects of five factors: soil [clay vs. loam], age of seedling [20-day vs. 8-day – with colder temperatures, the onset of the 4 th phyllochron of growth is later than at Morondava], seedlings per hill [3 vs. 1], water management [continuous flooding vs. water control, with deliberate aeration of the soil during the vegetative growth period], and nutrient amendments [none vs. NPK vs. compost]. The reason why there are only 240 trials rather than 288 is that trials with no amendments were done only on the clay soil plots, not on the poorer loam soil plots, which were known to have low inherent fertility. This made for 40 combinations, with six replications. [The spacing factor as in the Morondava trials was not significant, with a difference of only 80 kg/ha for the two sets, each N = 120.] Again, all yields reported are averages for 6 replicated plots randomly distributed.
- This is a SRI rice nursery in Sri Lanka, showing one way (but only one of many ways) to grow young seedlings. The soil in this raised bed was a mixture of one-third soil, one-third compost, and one-third chicken manure. (The flooding around it is because the surrounding field is being readied for transplanting; normally there would not be so much water standing around the nursery.)
- Here the seedlings are being removed. We would recommend that they be lifted with a trowel, to have minimum disturbance of the roots, but these seedlings are so vigorous that this manual method is successful. This farmer has found that his seedlings, when transplanted with two leaves at time of transplanting, already put out a third leave the next day after transplanting, indicating that there was no transplant 'shock.'
- Here the field is being 'marked' for transplanting with a simple wooden 'rake.' If the soil is too wet, these lines will not remain long enough for transplanting. There are drains within the field to carry excess water away from the root zone.
- Here are seedlings being removed from a clump for transplanting. Note that the yellow color comes from the sunlight reflecting off the plant. The plant's color is a rich green, indicating no N deficiency.
- Here the seedlings are being set into the soil, very shallow (only 1-2 cm deep). The transplanted seedlings are barely visible at the intersections of the lines. This operation proceeds very quickly once the transplanters have gained some skill and confidence in the method. As noted already, these seedling set out with two leaves can already have a third leaf by the next day.
- The SRI field looks rather sparse and unproductive at first. Up to the 5th or 6th week, SRI fields look rather miserable, and farmers can wonder why they ever tried this method and 'wasted' their precious land with such a crazy scheme. But the SRI plot here will yield twice as much rice as the surrounding ones once the rapid tillering (and root growth) begins between 35 and 45 days.
- This is one of many happy Sri Lankan farmers with his SRI field nearing harvest time. Some young farmers have taken up growing "eco-rice," i.e., traditional varieties grown organically to be sold for a much higher price than conventional HYV rice, because of better texture, taste, smell and aroma and more assurance of healthy food. SRI in this way is starting to contribute to the preservation of rice biodiversity. As noted above, SRI methods work well with hybrid varieties and HYVs. These give the highest yields with SRI methods. But as SRI methods can double or triple traditional-variety yields, these old varieties become economically more advantageous with SRI. Much more remains to be learned about and from SRI. But we have now enough accumulated evidence, based on experience in farmers' fields, not just on experiment stations, and consistent with what is known in the literature (though often not previously connected up to promote increased rice productivity), to have confidence that this methodology will contribute to greater food security and a better environment. SRI, developed by Fr. de Laulanie and promoted by his friends in Association Tefy Saina, and by a growing number of colleagues in many countries around the world, could help to improve other crop production. The world does not need a doubling of rice production, but it does need increased productivity in the rice sector, as this is the largest single agricultural sector in the world in terms of the resources devoted to it. By raising the productivity of land, labor, water and capital in the rice sector, we should be able to meet our staple food needs with less of these resources, which have significant opportunity costs. We hope that SRI methods will enable farmers to redeploy some of their land, labor, water and capital to producing other, higher-value and more nutritious crops, thereby enhancing the well-being of rural households and urban populations. The urban poor should benefit from lower prices for rice that will follow from higher productivity. SRI is not a labor-intensive method that will 'keep rice production backward,' as was alleged by its critics in Madagascar for many years, but a strategy for achieving diversification and modernization in the agricultural sector.