Slides for presentation in the CIIFAD seminar series at Cornell University, September 15, 2004. These slides can be used or adapted, even translated, to assist SRI colleagues in explaining this methodology to others.
This is a bold claim, but it is the starting point for understanding SRI. We say this based on growing experience with SRI methods and results from around the world, including half a dozen African countries.
Probably no innovation in the agricultural sector can produce as many benefits as SRI, as will be seen below. People are entitled to be skeptical because SRI raises, all at the same time, the productivity of the land, the labor, the water, and the capital devoted to rice production – something that economists would expect to be impossible because they always look for tradeoffs. SRI ‘breaks the rules’ as will be seen, but not by any magic. Rather, by following practices and principles that have a sound scientific basis.
Because we have seen SRI methods succeed so often, and often spectacularly, in a wide variety of conditions, we have confidence that if they are given a fair test, they will prove themselves under most circumstances. Because we are dealing with biological phenomena, one does not get the same results each time or everywhere. In biology, small inputs can yield big outputs – under favorable conditions, with a good environment for growth; or a lot of inputs can produce no output at all – if conditions are unsuitable for sustaining growth. But 90% of the time, we have had positive results with these methods, so we are confident in recommending that they be tried.
This picture was provided by Dr. A. Satyanarayana, director of extension for the Indian state of Andhra Pradesh. In January 2004, I visited the field where this plant (and others) were being grown and saw how vigorous the plants were. This picture was taken shortly before harvest. Under usual growing conditions, the variety is productive and favored for its good grain quality, but it does not tiller like this without SRI practices.
Picture provided by Dr. P. V. Satyanarayana, the plant breeder who developed this very popular variety, which also responds very well to SRI practices.
Picture provided by Gamini Batuwitage, at the time Sr. Asst. Secretary of Agriculture, Sri Lanka, of SRI field that yielded 13 t/ha in 2000, the first year SRI was used in that country. Such performance got SRI started there..
Picture provided by Dr. Rena Perez of SRI field in 2002 at the cooperative where SRI got its start in Cuba. This field gave yields of about 6 t/ha before. This cooperative has expanded from 2 ha to 20 ha in SRI.
This field was harvested in March 2004 with representatives from the Department of Agriculture present to measure the yield.
This is a brief historical background. Fr. de Laulanie came to Madagascar from France in 1961 and started working on improvement of rice opportunities for the people there. It was not even tried anywhere outside China until 1999 (Nanjing Agricultural University), but it is now spreading rapidly. Vietnam is the 21 st country where SRI results have been demonstrated and documented. The 19 th and 20 th were Mozambique and Senegal. Fr. de Laulani é came to Madagascar from France in 1961 and spend the next (last) 34 years of his life working with farmers to evolve a system that could address their problems of hunger and poverty, with minimum dependence on external inputs. His only published writing on SRI and its ‘invention’ is his article published in 1993 in the journal Tropicultura (Brussels), Vol. 11, pp. 110-114. “The father of SRI” is a real father. In 1990, with Malagasy friends who were similarly committed to rural development in Madagascar, he established an NGO, Association Tefy Saina , which carried on his work after his death in 1995.
Fr. de Laulanie was born in 1920 and got a first degree in agriculture from the agricultural college in Paris that has become Paris-Grignon, the leading French agricultural university. He graduated in 1939 but decided not to pursue agriculture, given the changes in his and others’ lived caused by the outbreak of World War II, and entered a Jesuit seminar in 1941 to make his life one of service, graduating in 1945. In 1961, as noted on the previous slide, he was sent by the Jesuit order to Madagascar, where decided that he could probably make his greatest contribution to others’ welfare by helping to improve rice productivity.
Rafaralahy and Rabendrasana began working with Fr. de Laulanie in the mid-1980s while they were directing the government’s handicraft (artisanat) agency and assisted him with the school for young farmers that he had established in Antsirabe. In 1990, after it became clear that the government was not going to give any assistance or boost to SRI, Sebastien and Justin and some other friends joined Fr. de Laulanie in forming Tefy Saina, resigning their government jobs to bring the benefits of SRI to their fellow Malagasys. In 2003, Sebastien and Justin received the award for Environmental Protection the European Slow Food Movement based in Naples, Italy.
This is the most succinct statement of what SRI ‘is.’ We emphasize the principles and methods rather than techniques because we regard SRI as a ‘methodology’ rather than as a ‘technology.’ SRI is not a fixed set of practices but rather involves practices that we know can succeed to the extent that they apply, appropriately for the conditions, the principle that constitute SRI.
Scientists in many countries and international institutions have been slow to accept the possibility that SRI represents something new and productive, but Chinese scientists have been evaluating SRI since 1999. It is increasingly accepted in that country. So have Indonesian scientists at that country’s rice research institute (at Sukamandi, one of the centers for the Green Revolution), where after three years of evaluation, SRI practices were incorporated into the government’s strategy for reviving the growth of rice productivity which had stagnated over the past half dozen years. Scientists at major agricultural universities in India have also demonstrated SRI merits. So scientists at the leading institutions in the three largest rice-producing countries are ‘on board’ with SRI, even if the International Rice Research Institute is withholding support. The director-general of the West African Rice Development Association (WARDA), Dr. Kanayo Nwanza, has been supporting SRI evaluation and principles since 2000.
This figure shows research findings from the China National Rice Research Institute (CNRRI), published in the proceedings of the first international SRI conference, held at Sanya, China, in April 2002. Two different rice varieties were used with SRI and conventional (CK) methods. The second variety responded more positively to the new methods than did the first in terms of leaf area and dry matter as measured at different elevations. But both varieties had more leaf area and dry matter when grown with SRI methods than with conventional methods.
This graph shows results from research on SRI done by the Sichuan Academy of Agricultural Sciences. Same findings were found at the full heading stage (except there was less dry matter in the panicle). [With. Leaf stands for Withered Leaf.]
More data from the Sichuan Academy of Agricultural Sciences comparing the length and width of leaves between SRI-grown and conventionally-grown rice (same variety) showing the difference in phenotype resulting from SRI practices.
Figure from Sichuan Academy of Agricultural Sciences research on SRI, comparing the leaf area of SRI rice plants with conventional rice plants, with same variety and otherwise the same growing conditions.
SRI has been hard to get accepted because it does not depend on either of the two main strategies of the Green Revolution: it does not require any change in the rice variety used (genotype) since the methods evoke more productive phenotypes from any rice genotype; nor does it require an increase in external inputs -- the latter can in fact be reduced. Water requirements and costs of production can also be reduced. This sounds truly ‘too good to be true,’ but pictures above showed how the plant can become a more vigorous and productive organism, able to acquire more nutrients and sustain larger panicles of rice.
Yield is a simple, usually dramatic number to talk about. But it is less important than profitability (at which SRI excels) and factor productivity (SRI is the only innovation to raise the productivity of four resources simultaneously, something most economists would regard as impossible because they always expect to have tradeoffs). By utilizing existing biological processes and potentials, SRI breaks out of the usual constraint of zero-sum relations and diminishing returns. This makes it hard for many to understand and accept SRI at first. But in recent years, we have gained a reasonable understanding of SRI processes from experience, from controlled experiments, and from the literature. SRI is fully understandable and explainable within what is already known in the realms of plant physiology, genetics, and soil biology and ecology.
Madagascar rice yields have averaged around 2 t/ha for many years, with little increase. Farmers using SRI have often averaged 8 t/ha, with some getting twice this or more from best use of SRI practices. See next slide for details from a French report. World Vision/Sierra Leone sent an agronomist to Madagascar in Nov. 2000 to learn about SRI. Farmers in 8 villages tried the methods in 2001 and got more than doubled yield (reported by Abu Yamah, World Vision/Sierra Leone). Ten Gambian farmers who came to a field day at the Sapu research station of the National Agricultural Research Institute in 2000 (where SRI trials produced 5.4-8.3 t/ha) tried SRI methods on their farms the next year, dividing their fields in half. They got almost a tripled yield with SRI methods compared to their usual methods, as reported by a former director of the Sapu station, Dr. Mustapha Ceesay. A reader of the NGO newsletter ECHO DEVELOPMENT NOTES read about SRI in 2001 and got a government agriculturalist in Benin to try the methods side-by-side plots. The SRI plot yielded almost five times as much as the control plot with conventional methods (reported by Elyse Merritt, ECHO).
The French development assistance program supported a small-scale irrigation system improvement project on the Haut Plateau for five years, 1994/95-1998/99. It was not introducing SRI as part of the project, but it was monitoring production. This table was compiled from Annexes 13 and 14 of a report by M. Robert Hirsch to the agency in 2000. The average yields with SRI compared to ‘improved methods’ involving external inputs and ‘peasant practice’ are very similar to the results that CIIFAD and its NGO partner, Association Tefy Saina, got working with farmers in the peripheral zone around Ranomafana National Park, east of Fianarantsoa. Farmer practice averaged 2 t/ha, and SRI averaged 8+ t/ha during this same period.
Dr. Jiming Peng, deputy director of the China National Hybrid Rice Research and Development Center, when introducing hybrid varieties developed in China to Guinea, used SRI methods as the CNHRRDC now does when promoting its new varieties because SRI methods add 1-2 t/ha to the yields obtainable with hybrids. He reported that they reached 9.2 t/ha with SRI and hybrid seeds in Guinea trials (personal comm.) Zelia Menete, a lecturer at Mondlane University, is doing research in Mozambique for her PhD thesis in crop and soil sciences from Cornell University. She is evaluating whether SRI could work on saline soils, of which here are a lot in her country. Her trials on saline soils, not using fertilizer and much less irrigation water, matched or exceeded the yields usually obtained in Mozambique on good soil with fertilizer and irrigation (personal comm.) She is doing a second season of trials and will report all the results in her thesis in 2005. Dr. William Settle (Plant Protection Division, FAO/Rome) got SRI trials started in Senegal. He recently reported that the first results are available. The first two control plots harvested produced 4 and 5 t/ha; the SRI plots adjoining them produced 9 and 11 t/ha (personal comm.) Most of the data available on SRI are reported by researchers, NGOs or individuals, not yet published on ‘the literature.’ But the results are quite consistent, enough so that following them up with in-country evaluations makes sense.
SRI started out being ‘labor-intensive,’ but this has now become an unfortunate stereotype. SRI requires more labor to begin, when farmers are getting acquainted with the methods and are learning them. But in Cambodia, several studies have shown SRI to be neutral or beneficial with regard to labor requirements. Farmers with three years of experience (N = 120) were interviewed, and 55% said SRI was ‘easier,’ 18% said ‘more difficult,’ and 27% said ‘ no difference.’ In a study of 400 SRI users randomly chosen in 5 districts (not all using the full set of SRI practices), yields were increased by almost 50% and profitability by 100%. The SRI in labor requirement was 1% more, but farmers preferred it because they saved 10 days of labor/ha for transplanting, which came at a time of peak labor demand, and the increased requirement for weeding (when fields were not kept flooded) came later when labor was more flexibly available. An evaluation by the International Water Management Institute (Research Report No. 75, 2004) found that SRI required more labor, but labor productivity went up by 50% in the dry season and 62% in the wet season, so the returns to labor were much higher, justifying the greater input of labor. For small farmers, who depend more on their labor than their land for household income, higher labor productivity is most important. Farmers find that over time, as they master the techniques, they can reduce their labor inputs, even below pre-SRI levels. We expect also that many labor-saving methods and implements will be developed, particularly by farmers, so that in the years ahead, SRI labor requirements will diminish.
This was developed in 2003 by Mr. L. Reddy, to replace the use of strings and sticks to mark lines for planting, or the use of a wooden “rake” that could mark lines when pulled across the paddy in two directions. This implement, which can be built for any spacing desired, enables farmers, after it is pulled across the paddy in one direction, to plant SRI seedlings in a 25x250 cm square pattern. It saves as lot of labor time for transplanting because only one pass is needed across the field, and this is wider than a rake could be. Even wider ones have been built. Mr. Reddy is a very innovative and successful SRI farmer, with a superb yield last rabi season, measured and reported by the Department of Extension in Andhra Pradesh.
Mr. Swaminathan built this weeder which removes weeds and aerates the soil at the same time so that four rows can be simultaneously cultivated/weeded, cutting the required time in half. He has also devised an innovative system for crop establishment that is especially suited to hot climates. He has named it the Kadiramangalam system, and it is described on the SRI home page (http://ciifad.cornell.edu/sri/) We welcome farmer innovation and expect it to continue to improve SRI methods and performance.
This was built by Luis Romero, one of the first successful SRI farmers in Cuba, to plant germinated seeds at 40x40 cm spacing. The seeds are put in the respective bins and are dropped on the field in a square pattern as the bins rotate. For his field conditions, Luis found that 40x40 cm was too wide because of weed problems. The canopy did not close quickly enough. So he has built one with less wide spacing. His neighbor built a seeder with 12 bins, four times as wide, that can be pulled by oxen to further save labor. The important thing to note is that farmers are working on their own ways to reduce SRI labor requirements because they see the benefits of wide spacing, aerated soil, etc.
The main constraint for getting best results with SRI is water control. Once everyone accepts that significant productivity increases are possible with SRI, farmers and governments should become more willing to invest in the infrastructure and organization needed to control water better. Governments in particular have an incentive to try to reduce the agricultural sectors’ demands for water given the growing scarcity of water with competing demands. Roland Bunch, well-known international expert on rural development, reported from a village in Cambodia which he visited in May 2003 as a consultant for the NGO ADRA, that 100 farmers there had tried SRI at the urging of ADRA. Because they were very poor, getting only 1 t/ha average yield from their rice, partly because they do not have good water control, to get them to try SRI, ADRA promised the farmers that it would compensate any who lost yield as a result of using SRI methods. Bunch reported that the farmers had averaged 2.5 t/ha, and none had asked for any compensation. All were satisfied (many more than satisfied) with their yield. SRI requires some investment in farmer training and motivation, at least initially, until there can be farmer-to-farmer spread. But getting farmers to become more experimental about their rice production, to try out ideas and to evaluate differences in plant yield or health attributable to spacing, water applications, etc. helps them become more innovative and confident. SRI was developed and promoted as much for human resource development as for raising rice production. (“Tefy Saina” in Malagasy means “to improve the mind.”) It has been seen in a number of countries that SRI is making farmers more interested in experimentation and innovation, so that their farming gets improved overall. Disadoption has been documented in Madagascar (Moser and Barrett, Agricultural Systems , 2003, but we are not seeing it as a problem elsewhere. Some disadoption is likely for any innovation. But in Cambodia, where SRI has been well introduced and institutionally supported, the number of farmers using SRI has gone from 28 in 2000, to 400+ in 2001, to 2600+ in 2002, to 9100+ in 2003, to over 20,000 in 2004, with greater and greater interest and demand. This is driven by the fact that for Cambodian farmers, SRI reduces their need for labor, cash expenditure, water and seed. SRI is not a fixed technology but rather a set of ideas that get adapted to improve rice production. Disadoption is a possibility and sometimes a reality, but it is not inherent in SRI. One problem that is localized but that can be serious is the emergence of harmful nematode populations (most nematodes are beneficial or neutral) in Thailand. This may account for why SRI results in Thailand and in Laos have been less impressive than elsewhere, e.g., in neighboring Cambodia and Myanmar. We need to be alert to such problems with SRI and to work on ways to overcome any problems as they arise. In Cuba, experimentation is being done on different schedules of irrigation that can control weeds. This might also control nematodes without sacrificing too much yield.
There have been several recent journal articles critiquing (dismissing) SRI. Unfortunately, the claims are not based on any systematic knowledge of SRI. An article in Field Crops Research by Sheehy et al. (2004) relied on data from three small trials done in China, not following any protocol that qualified as proper SRI methodology. One of the trials had so much N fertilizer applied that the SRI rice lodged, something rare (because SRI should be done with little external fertilization and preferably with organic fertilizers). Had that trial not been biased, the balance of evidence even from these unrepresentative trials would have favored SRI. A more serious deficiency in the article was that the authors ignored the 4-5 years of research results from leading rice research institutions in China (the China National Rice Research Institute, the China National Hybrid Rice Research and Development Center, the Sichuan Academy of Agricultural Sciences, China Agricultural University, Nanjing Agriculture University) when making these dismissive claims. All these institutions have validated SRI to their satisfaction. A growing number of first-rate scientists in China and elsewhere are engaging with SRI so that soon the accumulation of scientifically-acceptable data will soon make these dismissive claims irrelevant. The growing use of SRI by farmers around the world will be the most conclusive refutation.
This is the first explanation for why SRI produces remarkable results. With wider spacing supporting greater root and canopy growth, we get ‘the edge effect’ for the whole field. This effect should be avoided when making estimates of yield, but it should be welcomed agronomically. One wants larger, healthier plants for the whole area, not just around the edge.
(1) Alternate wetting and drying of paddy soils with SRI methods will increase the proportion of plant N that comes in the form of nitrate. This, according to IRRI research, will enhance yield by 40-60%, so just the change in water management could contribute a lot of ‘the SRI effect.’ (2) This change in water management will also increase biological nitrogen fixation (BNF), according to research done at Cornell over 30 years ago. Apparently the microbes that fix nitrogen are more active at the interface between aerobic and anaerobic soil horizons. (3) When soil is not kept flooded, the growth of aerobic bacteria on roots, and the grazing of these organisms by protozoa, will increase, especially with larger canopies and larger root systems putting out more exudation into the rhizosphere. Because protozoa have a lower C:N ratio than the bacteria they consume, they excrete the ‘excess’ N into the root zone. Published estimates of this N contribution to plant nutrition indicate that this can reach 20-40% of plant N, a source that rice plants are deprived of with continuous flooding. Also, more and more evidence is accumulating on contributions that endophytic bacteria make to plant nutrition and to other processes benefiting plants (e.g., Dobbelaere et al., 2003). (4) The endophytic contribution we have some direct evidence on (see next slide).
These data were reported by Prof. Robert Randriamiharisoa, head of the Agriculture Department at the University of Antananarivo before his untimely death in August 2004, to the Sanya conference in 2002. They give the first direct evidence of the contribution that soil microbes make to the high 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. It was an organism that could be reliably studied and counted with laboratory facilities in Madagascar. Somewhat surprisingly, there was no significant difference in Azospirillum populations in the rhizosphere (the soil around the roots). 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 produced very good results, on clay soil a yield five times higher than traditional methods and no amendments. But compost used with SRI gives a yield six times higher. NPK decreases Azospirillum (and other) microbial populations, so most/much of the N that produced the 9 t/ha yield was coming from inorganic sources. The higher 10.5 t/ha yield obtained with compost depended entirely on organic N. Organic methods were capable of producing a tripling of yield on loam soil and a quintupling on clay soil. These kinds of evaluations will give somewhat different numbers according to soil quality, variety used, etc., but the overall relationship seen here should be quite robust. 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 in Madagascar. Tragically, Prof. Randriamiharisoa, who initiated this work, passed away in August, 2004, so we will no longer have his acute intelligence and probing mind to advance these frontiers of knowledge.
The article by Turner and Haygarth published in Nature opened up a new line of explanation for SRI results. Turner has visited Madagascar and is trying to get research started on how SRI methods may be mobilizing ‘recalcitrant’ P (esp. in inositol phosphate form) to get higher yields even when the measured ‘available’ P is very low (as it was around Ranomafana where we began our SRI work – 3-4 ppm). Microbes can ‘mine’ the soil to bring unavailable P into the pool of available P.
It is well known that mycorrhizal fungi improve nutrition and protection against biotic and abiotic stresses in most terrestrial plants. Irrigated rice has been denied these benefits for many years. Research needs to be done to confirm this hypothesis, but it is only one of a dozen or more explanations for why SRI practices raise yield so much. Half of our hypotheses could be proved wrong, and yet the other half would suffice if they are established.
Research on phytohormones goes back 50 years or more but has not been integrated into agronomic analysis, being left in the domain of microbiology. We see such huge increases in root growth (and such variation in this) that it seems apparent that root growth (and plant vigor) is promoted (or not) by soil organisms producing auxins, cytokinins, etc. See next two pictures.
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.
These two rice plants are ‘twins,’ planted on the same day in the same nursery from the same seed bag. The one on the right was taken out at 9 days and transplanted into an SRI environment. The one on the left was kept in the flooded nursery until its 52 nd day, when it was taken out for transplanting (in Cuba, transplanting of commonly done between 50 and 55 DAP). The difference in root growth and tillering (5 vs. 42) is spectacular. We think this difference is at least in part attributable to the contributions of soil microorganisms producing phytohormones in the rhizosphere that benefit plant growth and performance.
This figure is 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).
Barison did on-station trials at Beforona in Madagascar to compare many parameters of SRI vs. conventional rice plants. This shows the differences in root length density at different depths with different management practices. SRA stands for System de Riziculture Amelioree, system of rice improvement, promoted by government researchers using fertilizer, row planting, etc. – the ‘modern’ package in contrast with farmer practice.
This figure from a 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. At maturity, the SRI roots have still almost 3x the oxygenation ability of conventionally grown rice plants.
In on-farm research, Barison analyzed the rice plants on 108 farms where farmers were using both SRI and conventional growing methods, so that there would be minimal influence of inter-farm or inter-farmer differences. Same varieties and same soils. The QUEFTS modeling exercise is quite standard in plant evaluation. The SRI plants had a very different capacity to take up N (and P and K) and to convert them into grain.
This is an analysis just for N (but the results were essentially the same for P and for K), showing how the plants are more internally efficient at converting N into grain. Conventional plants plateau at about 5 t/ha; SRI plants plateau about 10 t/ha, showing that they are more efficient in using the N taken up by the roots.
This is becoming more evident as reports accumulate from different countries. Systematic research and documentation should be undertaken on this.
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.
Farmers in many countries have reported reduction in pests and diseases. A 70% reduction in sheath blight in Tian Tai country, Zhejiang province, reported to me during a field visit in August 2004, is representative of the kind of effects that farmers have observed, reducing their need to use agrochemicals. The improvements in grain quality are also widely observed and commented on. Millers in Andhra Pradesh now pay as much as a 10% premium for SRI paddy because of the higher outturn. See following data.
Prof. Ma Jun in his paper to the Haerbin conference included data on rice quality that he had collected. They showed SRI rice grains (from three different spacings within the SRI range) to be clearly superior in two major respects to conventionally-grown grains (two spacings). A reduction in chalkiness makes the rice more palatable. An increase in outturn is a ‘bonus’ on top of the higher yields of paddy (unmilled) rice that farmers get with SRI methods. We have seen this kind of improvement in outturn rates in Cuba, India and Sri Lanka, about 15%. More research on other aspects of SRI grain quality should be done, including nutritional content.
This warrants research. It is usually the case that larger grains have less nutritional value, being mostly starch. However, with the larger root system and more densely packed grains (higher grain weight without larger size), we have reason to believe that there are nutritional improvements.
This is an unanicipated benefit. Young farmers in Sri Lanka are using SRI to preserve ‘traditional’ varieties that they like and value, but that have been sidelined by ‘improved’ varieties that give higher yields with higher inputs. Old varieties do poorly with such methods. But with SRI, they perform very well, and command a higher price in the market place because of preferred characteristics of taste, keeping quality, etc.
The Paraboowa Farmers Association in Sri Lanka has a dozen ‘wild rice’ varieties that it can grow for marketing or for export. The rice is grown ‘organically’ so can get a premium price in overseas markets. 17 tons have been exported to Italy already. The farmers want to preserve these varieties for future generations, and are taking up SRI so they can do this – as well as get higher incomes. This enables them to do well by doing good.
SRI defies usual logic – that it takes more input to get more outputs. But our proposition that “less” can produce “more,” for a number of different but reinforcing reasons, can be well supported from the scientific literature.
SRI has only been known and used outside of Madagascar for five years. China and Indonesia were the first countries to validate its methods and begin using it, in 1999. With no project funding or donor support -- only two small grants from the Rockefeller Foundation, and support from CIIFAD, plus a lot of volunteered contributions of time and effort and the decentralized, small-scale support of many institutions around the world – SRI has by September 2004 been demonstrated in 21 countries: Bangladesh, Benin, Cambodia, China, Cuba, Gambia, Guinea, India, Indonesia, Laos, Madagascar, Mozambique, Myanmar, Nepal, Peru, Philippines, Senegal, Sierra Leone, Sri Lanka, Thailand and Vietnam. Leading research institutions in the three main rice-producing countries (China, India and Indonesia) have evaluated SRI for 3-5 years and are satisfied that it will make a major contribution to improving rice production in their countries.
Farmer experimentation and evaluation has been a central part of the extension strategy with SRI. In some countries, NGOs have offered to guarantee farmers that they will be compensated if their SRI yield is less than what they got with previous practices. We know of now instance where payment has been necessary. When ADRA made this offer to 100 farmers in Cambodia who had been getting 1 t/ha yields, their average was 2.5 t/ha with SRI and none asked for any compensation. This assurance can be made safely if all methods are applied, and applied as recommended. However, even with partial adoption of the methods, farmers usually get an increase in yield and profits.
SRI is pointing toward some new thinking that could help to reshape agriculture in this new century, when we need to get away from ‘extensive’ production which is very costly in terms of energy, and which does not use our land resources (shrinking in per capital terms) to their fullest advantage. The 20 th Century practices will not disappear, but we expect that new production systems more fully based on biological knowledge and practice will emerge.
The Madagascar trial was done with gliricidia mulch, chopped into 10 cm lengths, applied between single plants spaced 30x30xm, about 7 cm deep (which packed down to about 5 cm). Some chemical fertilizer was used in this trial along with compost. The Philippine trials (five spacings, shown on next slide, with four replications) involved planting 3-4 seeds at the indicated spacings and then at 10-12 days removing all biut the best plant in each hill, and then mulching (with sesbania) as in the Madagascar case. No chemical fertilizer was used, just chicken manure to give a rate of 60 kg N/ha, and with an organic foliar spray (seaweed extract) during the growth phase. Details provided upon request.
The NGO BIND, based in Bacalod City, Negros Occidental, adapted SRI concepts to upland (unirrigated) production, testing five spacings with four replications, in a 4,000 sq. meter area, relying only on rainfall. The fields were mulched with sesbania cuttings after the hills (planted with 3-4 seeds each ) had been thinned back at about 10 days after emergence to just one plant per hill. The mulch conserved moisture, suppressed weeds, and lowered soil temperature so that it was more hospitable to earthworms and other soil biota.
Ken Cassman and associates have figured that to raise rice production by 60% over the next 25 years, we will need to TRIPLE our use of N fertilizer. They said this to encourage research on how to use fertilizer more efficiently. But maybe we should be considering ways to get off the “N treadmill,” where larger and larger amounts are needed to achieve smaller and smaller increments. SRI with its emphasis on root growth and functioning and on the symbiotic relationships between plants and soil biota could open some new opportunities.
The ATI in Southern Mindanao, at Cotobato, tried SRI methods with three improved varieties in 2002 with these results. The average yield of 12 t/ha contrasts with IRRI’s first SRI yield at Los Banos of 1.44 t/ha. That poor result reinforced my thinking that differences in soil biota must be part of the SRI effect, as IRRI soils have had fertilizers and agrochemicals applied in abundance for 30 years, surely affecting the soil biotic populations. In Mindanao, such inhibition is less of a problem. The economic returns calculated are more important than the yield figure.
Dr. Aldas 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. Having been on the IRRI agricultural economics staff in Los Banos from 1999 to 2002, he had previously done such an evaluation for IRRI of the costs and benefits of adopting hybrid rice. He found SRI to be a more profitable innovation for rice production than adoption of hybrids. We have found that SRI methods give the highest yields with hybrid varieties (often over 15 t/ha) so there is no contradiction or competition between the two. SRI methods add to the higher yield obtained with hybrid varieties. The China National Hybrid Rice Research and Development Institute, which originated hybrid rice, when it brings its varieties to African countries recommends mostly SRI practices. 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.
These summary data are taking from an evaluation reported in a paper to the ICID in November 2003; the full report is available now from IWMI as Research Report 75.
Dr. DeDatta, one of the leading authorities on rice having headed IRRI’s agronomy department for more than a decade and whose text on rice is often referred to as ‘the bible on rice,’ acknowledges the importance of soil biota. But the text pays little attention to them. Roots are similarly ignored. In DeDatta’s text, there is no a single entry on roots in his index of over 16 pages (1100+ entries). One subentry refers to the rhizosphere, to a single sentence saying that there is a rhizosphere, nothing more. Roots and soil biology have been greatly under-researched in the plant and soil sciences. These are areas where there is likely to be highest returns to research investments in the future, especially for the kind of environmentally sound agricultural development needed in the 21st
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. Recent research has documented how different plant, soil and nutrient management, affecting the roots, is associated with changes in gene expression in the cells of leaf tissues, with genes for plant senescence and disease resistance being turned on or off according to different management practices. See article by Kumar et al. in PNAS (Proceedings of the National Academy of Sciences), July, 2004.
Katayama’s research, on wheat and barley as well as rice, was not published until after World War II, and was never translated into English, so it is not widely known. It is approximated in the analysis of ‘degree-days,’ but understanding of phyllochrons is more sophisticated physiologically. They are not widely known among English-reading scientists, but they are now known and studied by wheat scientists (see Crop Science special issue, July 1995, Vol. 35, No. 1) and some forage scientists, because they are relevant for these plants as they are for rice. The following slide shows the table that Fr. de Laulanie worked out once he became acquainted with phyllochrons through a book on rice production by Didier Moreau (1987), published by GRET, Paris.
This is a table that Fr. de Laulanie worked out based on the work of the Japanese scientist Katayama who studies (discovered) phyllochrons as a regular interval of plant growth in gramineae species (rice, wheat, barley). For more on this, see Stoop et al. (2002) in AGRICULTURAL SYSTEMS.
This shows graphically the pattern of tiller growth that is possible with an intact and functioning root system in rice plants – 84 tillers within 12 cycles of growth (12 phyllochrons). Some rice plants have over 100 tillers, in which case, they have entered into the 13 th phyllochron of growth.
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  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 was the situation as of early 2004. Vietnam now has shown the SRI effect and is starting a program for wider use.
Situation as of mid-2004.
Situation in mid-2004.
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.) The nursery is build up with three lengths of bamboo, to raise it and keep it dryer, and so that the improved nursery mix can be easily put into the frame for 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, can already put out a third leave the next day after transplanting which indicates that there was no transplant 'shock.‘ Usually when transplanting is done in the conventional way, it takes 7-14 days for the transplanted seedlings to recover from the shock and resume their growth.
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. The roller-market shown in slide 29 is starting to be used in India and will surely spread to other countries. It can be fabricated locally in India for about $6. This wooden rake costs about 50 cents. The saving in time makes the more elaborate implement a good investment.
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 actually a rich green, indicating no N deficiency. Their quick recovery from the transplanting shows their health and vigor. At this young age, the seed sac is still attached to the root and should be kept attached during the transplanting process. If the nursery soil is like the one described for slide 77, the seedlings can be easily separated for transplanting. There is not great harm or loss if two are transplanted together, but single seedlings in good soil give better yield than two seedlings together. Once transplanters get used to the new method, they find it easier (less back pain) and quicker. In Cambodia, farmers now say that they save 10 days of work per hectare with SRI transplanting methods.
This is the most important picture in the set. Here the seedlings are being set into the soil, very shallow (only 1-2 cm deep). Notice that the seedlings already transplanted 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. At first, farmers may wonder why they ever tried this method and 'wasted' their precious land with such a crazy scheme. But the SRI plot seen here will yield twice as much rice as the surrounding ones, once the rapid tillering (and root growth) begins between 30 and 45 days. By the end of the season, rice plants can have expanded and flourished like the ones seen in the opening slides.
This is one of many happy Sri Lankan farmers with his SRI field nearing harvest time. Some young farmers have taken up growing &quot;eco-rice,&quot; 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.
0428 An Opportunity for Africa: The System of Rice Intensification (SRI) [ le Systéme de Riziculture Intensive ]
An Opportunity for Africa: The System of Rice Intensification (SRI) [ le Syst éme de Riziculture Intensive ] Norman Uphoff, Cornell International Institute for Food, Agriculture and Development (CIIFAD) Cornell University, Ithaca, NY, USA
For Centuries, Even Millennia, We Have Been ABUSING and MISTREATING the Rice Plant <ul><li>We have FLOODED it – drowning its roots </li></ul><ul><li>We have CROWDED it – inhibiting the growth potential of its canopy and roots </li></ul><ul><li>Now we apply various FERTILIZERS and chemical BIOCIDES affecting the soil biota which provide valuable services to plants: N fixation, P solubilization, protection against diseases and abiotic stresses, etc. </li></ul>
SRI Offers an Opportunity to Raise Rice Production Significantly <ul><li>Increasing yield by 50-100% or more: </li></ul><ul><li>Without changing varieties or requiring purchase of new seeds (any variety works) </li></ul><ul><li>Without requiring purchase of fertilizer since compost can give better results </li></ul><ul><li>Using 25-50% less water if irrigating rice, or adapting SRI for rainfed cultivation </li></ul><ul><li>No need for agrochemicals because SRI plants are reasonably resistant to pests and diseases </li></ul>
SRI Sounds ‘Too Good to be True’ – But It Offers Real Advantages <ul><li>SRI utilizes basic biological processes and dynamics to evoke a more productive PHENOTYPE from any rice genotype </li></ul><ul><li>It does this by changing the way that PLANTS, SOIL, WATER and NUTRIENTS are managed – changing practices that are centuries-old, but yield-constraining </li></ul><ul><li>SRI results can be explained based on solid scientific knowledge – but we are not proposing its adoption - only its evaluation </li></ul>
A single rice plant grown with SRI methods from a single seed (Swarna), in Andhra Pradesh, India, 2003-04 season
Roots of a single rice plant (MTU 1071) grown at Agricultural Research Station Maruteru, AP, India, 2003 season – Roots are the key to SRI success
SRI field in Sri Lanka -- yield of 13 t/ha with some panicles having 400+ grains
CFA Camilo Cienfuegos, Cuba 14 t/ha -- Variety Los Palacios 9 – former yield on this field was 6 t/ha
SRI field in Ambatovy, Madagascar with traditional variety
The System of Rice Intensification <ul><li>Was evolved in Madagascar over 20 yrs by Fr. Henri de Laulanié, S.J. – working with farmers, observing, experimenting, also having some luck in 1983-84 season </li></ul><ul><li>SRI is now spreading in countries around the world: positive results already in 21 </li></ul><ul><li>Association Tefy Saina was set up in 1990 by Fr. de Laulani é and Malagasy friends to promote SRI and rural and human development in Madagascar; ATS has been cooperating with CIIFAD since 1994 </li></ul>
Fr. de Laulani é not long before he died in 1995
Sebastien Rafaralahy and Justin Rabenandrasana, president and secretary of Association Tefy Saina
SRI in Summary : <ul><li>A set of principles/methods that get more productive PHENOTYPES from any existing GENOTYPE of rice. </li></ul><ul><li>SRI changes the management of plants, soil, water, and nutrients: </li></ul><ul><li>(a) To induce greater ROOT growth </li></ul><ul><li>(b) To nurture more abundant and diverse populations of SOIL BIOTA </li></ul>
SRI Practices Should Always be Varied to Suit Conditions <ul><li>The four basic practices of SRI: </li></ul><ul><li>Young seedlings ( < 15 days ) are used – though direct-seeding is becoming an option </li></ul><ul><li>Wide spacing – single plants, in square pattern </li></ul><ul><li>Soil aeration – thru water management and weeding, so aerobic conditions prevail in soil </li></ul><ul><li>Organic matter is added to enhance the soil – if enough compost is used, fertilizer not needed </li></ul><ul><li>Weed control with ‘rotating hoe’ is recommended </li></ul>
Simple mechanical push-weeder called ‘rotating hoe’ which aerates the soil while it eliminates weeds
Weeding of SRI fields in Madagascar, aerating the soil to stimulate root and plant growth
All Organisms Are Phenotypes <ul><li>i.e., the result of interaction between genetic potential and environment </li></ul><ul><li>SRI practices change the growing environment for rice plants – with wider spacing to encourage growth of canopy and roots; aeration of soil to encourage the growth of roots and soil organisms </li></ul><ul><li>Most evidence of phenotypical change comes from Chinese research: here are examples of research findings </li></ul>
Plant Physical Structure and Light Intensity Distribution at Heading Stage (CNRRI Research --Tao et al. 2002)
Dry Matter Accumulation between SRI and Control (CK) Practices (kg/ha) at Maturity (Zheng et al., SAAS, 2003)
Table 2. Different Sizes of the Leaf Blade (cm) with SRI Practices (Zheng et al., SAAS, 2003) 11.98 15.95 7.96 18.49 19.11 14.97 9.79 14.59 % Δ 0.20 8.86 0.16 9.00 0.30 9.29 0.14 8.18 +/- 1.67 55.56 2.01 48.67 1.57 62.03 1.43 56.07 CK 1.87 64.41 2.17 57.67 1.87 71.32 1.57 64.25 SRI Width Length Width Length Width Length Width Length Average Flag leaf 2 nd leaf 3 rd leaf Prac-tice
Figure 1. Change of leaf area index (LAI) during growth cycle (Zheng et al., 2003)
Different P aradigms of Production <ul><li>The GREEN REVOLUTION paradigm: </li></ul><ul><li>(a) Changed the genetic potential of plants, and </li></ul><ul><li>(b) Increased the use of external inputs -- more water, fertilizer, insecticides, etc. </li></ul><ul><li>SRI changes certain management practices for plants, soil, water and nutrients, in order to: </li></ul><ul><li>(A) Promote the growth of root systems , and </li></ul><ul><li>(B) Increase the abundance and diversity of </li></ul><ul><li>soil organisms , at the same time that they </li></ul><ul><li>(C ) Reduce water use and cost of production </li></ul>
Greatest Benefit Is not YIELD <ul><li>Yield can vary, often widely; for farmers, profitability is more important </li></ul><ul><li>From society’s perspective, what is most important is factor productivity – kg of rice per land, labor, capital, and water </li></ul><ul><li>No question any longer of whether SRI methods give higher yields/productivity but rather how to explain these changes </li></ul><ul><li>For some things, we have evidence ; for others, strong hypotheses from literature </li></ul>
There must be some, but they are few: <ul><li>The main constraint has been SRI ’s initial labor intensity – while farmers learn methods </li></ul><ul><li>This is receding as a constraint ; it is mostly a problem for first several weeks or seasons </li></ul><ul><ul><li>GTZ evaluation in Cambodia (N = 400) showed little increase (305 vs. 302 hrs/ha) -- and better timing </li></ul></ul><ul><ul><li>IWMI evaluation in Sri Lanka (N = 120) showed labor productivity to be increased by 50-62%, with just partial use of SRI methods; SRI labor pays </li></ul></ul><ul><li>Farmer innovation is helping to reduce labor requirements; more innovations will come; SRI can even become labor saving over time </li></ul>
Roller-marker devised by Lakshmana Reddy, East Godavari, AP, India, to mark a square pattern on field and save time in transplanting operations; his yield in 2003-04 season was 16.2 t/ha paddy rice (dry weight)
4-row weeder designed by Gopal Swaminathan, Thanjavur, TN, India
Other ‘Negatives’ <ul><li>Water control is needed for best results --this constraint can often be solved by better infrastructure and/or organization – SRI will make such investments pay </li></ul><ul><li>Some yield improvement without water control </li></ul><ul><li>F armer learning and skill are needed, but this is a benefit as well as a cost </li></ul><ul><li>Disadoption has been reported as a problem, but only in Madagascar so far </li></ul><ul><li>Nematodes can be a problem (e.g., Thailand) </li></ul>
SRI Has Been Called a ‘Niche Innovation’ <ul><li>(Dobermann, Agricultural Systems , 2004) – but there is no systematic evidence to support this claim </li></ul><ul><li>CHINA: SRI is adding 2-3 t/ha to yields in the north (Heilongjiong), south (Guizhou), east (Zhejiang) and west (Sichuan) </li></ul><ul><li>INDIA: Similarly, SRI added 2-3 t/ha across all 22 districts in Andhra Pradesh State, all having varying conditions </li></ul><ul><li>SRI is ‘not finished yet’ – still evolving, still improving </li></ul><ul><li>Already there are a number of explanations that are supported by data or that can be hypothesized based on the scientific literature </li></ul>
Biological Explanations Not all of these may prove to be correct -- but they provide more than enough scientific basis for SRI credibility
1 st Explanation? Above-Ground Environment <ul><li>SRI creates ‘ the edge effect ’ for whole field </li></ul><ul><li>Should avoid this only for measurement; should promote it agronomically </li></ul><ul><li>Too-close spacing affects photosynthesis within the canopy: measurements in Indonesia found that with normal spacing, lower leaves were being ‘subsidized’ by the upper leaves; wider spacing enables the whole plant to contribute </li></ul>
2nd Explanation? Nitrogen Provision <ul><li>Rice yields were increased 40-60% when the same amount of N is provided equally in both NO 3 and NH 4 forms vs. when all N is provided as NH 4 (Kronzucker et al., Plant Physiol. , 1998) </li></ul><ul><li>Biological N fixation (BNF) increases greatly with alternated aerobic/anaerobic conditions (Magdoff and Bouldin, Plant and Soil , 1970) </li></ul><ul><li>Protozoa can contribute significantly to N supply (Bonkowski, New Phytologist , 2004) </li></ul><ul><li>Endophytes (bacteria living in plant tissues, as symbionts, not parasites) also contribute </li></ul>
3rd Explanation? Phosphorus Solubilization <ul><li>This nutrient is often limiting factor, but </li></ul><ul><li>Large amounts of P in soil (90-95%) are present in ‘unavailable’ form </li></ul><ul><li>Alternating wetting and drying of soil increased P in soil solution by 85-1900% compared with soils just wet or just dry (Turner and Haygarth, Nature , May 2001) </li></ul><ul><li>Aerobic bacteria acquire P from ‘unavailable’ sources during dry phase; during wet phase they lyse and release P into the soil solution </li></ul>
4 th Explanation? Mycorrhizal Fungi <ul><li>90+% of terrestrial plants derive benefits from and even depend on mycorrhizal associations (infections) </li></ul><ul><li>Mycorrhizal hyphae extend into soil and expand volume accessible to the plant by 10-100x , acquiring water, P and other nutrients ; they also provide protective/other services to plants </li></ul><ul><li>Flooded rice forgoes these benefits </li></ul>
5 th Explanation? Phytohormones <ul><li>Aerobic bacteria and fungi produce auxins, cytokinins, gibberellins , etc. in the rhizosphere </li></ul><ul><li>Huge literature has documented effects of microbially-produced phytohormones (e.g., Frankenberger and Arshad, 1995) </li></ul><ul><li>Root growth in SRI plants probably is not due just to physiological processes within the plants --stimulated by aerobic microorganisms? Roots are key to SRI </li></ul>
Single Cambodian rice plant transplanted when 10-day-old seedling
Cuba – Two rice plants: same variety (VN 2084) and same age (52 days); 42 tillers on SRI plant vs. 5 tillers on the other
Dry Matter Distribution of Roots in SRI and Conventionally-Grown Plants at Heading Stage (CNRRI research: Tao et al. 2002) Root dry weight (g)
Table 13: Root Length Density (cm. cm -3 ) under SRI, ‘Modern’ (SRA) and Conventional Practice (from Barison, 2002) Results from replicated on-station trials 0.06 0.13 0.36 1.19 1.28 4.11 Conventional practice 0.07 0.15 0.31 0.55 0.85 3.24 SRA without fertilization 0.09 0.18 0.34 0.65 0.99 3.73 SRA with NPK and urea 0.20 0.25 0.32 0.57 0.71 3.33 SRI -- without compost 0.23 0.30 0.33 0.61 0.75 3.65 SRI -- with compost 40-50 30-40 20-30 10-20 5-10 0-5 Soil layers (cm) Treatments
Root Oxygenation Ability with SRI vs. Conventionally-Grown Rice Research done at Nanjing Agricultural University, Wuxianggeng 9 variety (Wang et al. 2002)
Figure 8: Linear regression relationship between N uptake and grain yield for SRI and conventional methods, using QUEFTS modeling (from Barison, 2002) Results are from on-farm comparisons (N = 108)
Figure 9: Estimation of balanced N uptake for given a grain yield for rice plants with the SRI and conventional systems, using QUEFTS modeling (same for P and K) (Barison, 2002) Results are from on-farm comparisons (N = 108)
Emerging Benefits from SRI These Should Be Evaluated Under Various Circumstances
<ul><li>1. Resistance to Abiotic Stresses – the climate is becoming more ‘extreme’ and more unpredictable, prepare for it </li></ul><ul><li>Observed SRI resistance to </li></ul><ul><ul><li>drought (Sri Lanka, several years) </li></ul></ul><ul><ul><li>hurricane (Sichuan – Sept. 2002) </li></ul></ul><ul><ul><li>typhoon (AP, India – Dec. 2003) </li></ul></ul><ul><ul><li>cold spell (AP, India – February 2004) </li></ul></ul><ul><li>Resistance to lodging probably due to greater root growth -- roots degenerate in continuously flooded soil </li></ul>
Two rice fields in Sri Lanka -- same variety, same irrigation system, and same drought : conventional methods (left), SRI (right)
<ul><li>2. Resistance to Pests and Diseases – widely reported by farmers – this probably reflects the protective services of soil microorganisms </li></ul><ul><li>3. Greater Milling Outturn ~ 15%: SRI paddy has 66 to 75% higher outturn in India; in Cuba, from 60 to 68-71%; adds to paddy yield </li></ul><ul><li>Fewer unfilled grains (less chaff) </li></ul><ul><li>Fewer broken grains (less shattering) </li></ul>
MEASURED DIFFERENCES IN GRAIN QUALITY Characteristic SRI (3 spacings) Conventional Diff. Paper by Prof. Ma Jun, Sichuan Agricultural University, presented at 10th conference on Theory and Practice for High-Quality, High-Yielding Rice in China, Haerbin, 8/2004 + 17.5 38.87 - 39.99 41.81 - 50.84 Head milled rice (%) + 16.1 41.54 - 51.46 53.58 - 54.41 Milled rice outturn (%) - 65.7 6.74 - 7.17 1.02 - 4.04 General chalkiness (%) - 30.7 39.89 - 41.07 23.62 - 32.47 Chalky kernels (%)
Emerging Benefits of SRI? <ul><li>4. Higher Nutritional/Health Value ? </li></ul><ul><li>SRI can be ‘organic rice’ that is free from agrochemical residues </li></ul><ul><li>Possibly SRI has higher nutritional quality in terms of micronutrients – this should be evaluated scientifically </li></ul><ul><li>Larger root systems give higher grain weight and greater grain density, so also greater nutrient density? </li></ul>
Emerging Benefits of SRI? <ul><li>5. Conservation of Rice Biodiversity ? </li></ul><ul><li>Highest SRI yields come with HYVs and hybrids (all SRI yields >15 t/ha) </li></ul><ul><li>But traditional/local varieties respond very well to SRI practice; can produce yields of 6-10 t/ha, and even more </li></ul><ul><li>Traditional rices receive higher price; higher yield with SRI makes them popular </li></ul><ul><li>Get an ‘organic premium’ for export? </li></ul>
LESS CAN PRODUCE MORE <ul><li>by utilizing biological potentials & processes </li></ul><ul><li>Smaller, younger seedlings become larger, more productive mature plants </li></ul><ul><li>Fewer plants per hill and per m 2 will give higher yield if used with other SRI practices </li></ul><ul><li>Half as much water produces more rice because aerobic soil conditions are better </li></ul><ul><li>Greater output is possible with use of </li></ul><ul><li>fewer or even no external/chemical inputs </li></ul><ul><li>Changes in management practices give different phenotypes from rice genomes </li></ul>
SRI STILL RAISES MORE QUESTIONS THAN WE HAVE ANSWERS FOR <ul><li>There are many researchable questions to be taken up by scientists, in association with farmers and extension personnel </li></ul><ul><li>But enough is known to pursue a two-pronged strategy : research and practice can proceed in parallel </li></ul>
Evaluating SRI Should be Low-Cost and without Any Evident Hazards <ul><li>SRI requires no purchases to try (except rotating hoes if possible) – just changes in practices </li></ul><ul><li>No chemicals are used, and there is no genetic modification involved </li></ul><ul><li>SRI can be tested and demonstrated on a small part of farmers’ fields – guarantee can be given of ‘no loss’ </li></ul>
SRI Experience Could Help Improve 21 st Century Agriculture <ul><li>Nurturing of roots and soil biota is relevant for much of agriculture </li></ul><ul><li>We need an agriculture that is </li></ul><ul><ul><li>Less ‘thirsty’ -- better roots will help </li></ul></ul><ul><ul><li>Less dependent on fossil-fuel energy sources -- fertilizer, mechanization </li></ul></ul><ul><ul><li>Less dependent on agrochemicals -- for sake of soil & water quality, for health </li></ul></ul>
SRI Concepts Have Been Extrapolated to Upland Rice <ul><li>In Madagascar, using mulch after directly planted seeds had emerged (plus wider spacing, organic inputs, etc.), an unirrigated yield of 4 t/ha obtained on farmer’s field in 1999 </li></ul><ul><li>In Philippines, similar methods without chemical fertilizer obtained average yield of 7.2 t/ha in 2002 on an upland unirrigated area of 4000 m 2 </li></ul>
SRI CONCEPTS CAN BE EXTENDED TO UPLAND PRODUCTION Results of trials (N=20) by the Philippine NGO, Broader Initiatives for Negros Development, with Azucena local variety (four replications -- 4,000 m 2 area, using mulch as main innovation, not young plants)
CAN WE CONTINUE TO RELY SO HEAVILY ON N FERTILIZE? To raise world rice production by 60% by 2030, N fertilizer applications will need to be tripled because of diminishing returns to fertilizer use (Cassman et al., 1998) <ul><li>Who believes this is feasible ? </li></ul><ul><li>Who believes this is desirable ? </li></ul><ul><li>Would it be economically possible ? </li></ul><ul><li>Would it be environmentally sustainable ? </li></ul><ul><li>SRI suggests that depending more on biology and less on chemistry may be effective – at least this option should be investigated </li></ul>
SRI Data from Sri Lanka <ul><li> SRI Usual </li></ul><ul><li>Yields (tons/ha) 8.0 4.2 +88% </li></ul><ul><li>Market price (Rs/ton) 1,500 1,300 +15% </li></ul><ul><li>Total cash cost (Rs/ha) 18,000 22,000 -18% </li></ul><ul><li>Gross returns (Rs/ha) 120,000 58,500 +105% </li></ul><ul><li>Net profit (Rs/ha) 102,000 36,500 +180% </li></ul><ul><li>Family labor earnings Increased with SRI </li></ul><ul><li>Water savings ~ 40-50% </li></ul><ul><li>Data from Dr. Aldas Janaiah, IRRI agric. economist, 1999-2002; now at Indira Gandhi Development Research Institute in Mumbai; based on interviews conducted with 30 SRI farmers in Sri Lanka, October, 2002 </li></ul>
IWMI Data from Sri Lanka <ul><li>IWMI Evaluation (Namara, Weligamage, Barker 2004) </li></ul><ul><li>60 SRI and 60 non-SRI farmers randomly selected: </li></ul><ul><li>YIELD -- increased by 50% on average, not doing full SRI </li></ul><ul><li>WATER PRODUCTIVITY -- increased by 90% </li></ul><ul><li>COST OF PRODUCTION (Rs./kg) -- lower by 111-209% with family labor, 17-27% at standard wage rate </li></ul><ul><li>LABOR PRODUCTIVITY (kg/hr) -- up 50% in yala (dry) season, and up 62% in maha (wet) season </li></ul><ul><li>PROFITABILITY -- increased by 83-206%, depending on the wage assumed (family labor vs. paid labor) </li></ul><ul><li>RISK REDUCTION -- conventional farmers had net losses in 28% of seasons, SRI farmers in only 4% </li></ul>
Contribution of SOIL MICROBIAL PROCESSES <ul><li>Microbial activity is known to be a crucial factor in soil fertility </li></ul><ul><li>“ The microbial flora causes a large number of biochemical changes in the soil that largely determine the fertility of the soil.” (DeDatta,1981, p. 60, emphasis added) </li></ul>
Bacteria, funguses, protozoa, amoeba, actinomycetes, etc. <ul><li>Decompose organic matter , making nutrients available </li></ul><ul><li>Acquire nutrients otherwise unavailable to plant roots </li></ul><ul><li>Improve soil structure and health -- water retention, soil aggregation, aeration, pathogen control, etc. </li></ul>
PHYLLOCHRONS <ul><li>The reason why transplanting young seedlings enhances crop yield is that transplanting should occur during the 2 nd or 3 rd phyllochron of growth , before tillering and root growth begin their acceleration. </li></ul><ul><li>Transplanting after about the 15 th day will cause greater trauma to the plant and affect its growth trajectory. </li></ul>
CAREFUL TRANSPLANTING <ul><li>Is a key element of SRI methodology </li></ul><ul><li>Trauma to the roots: </li></ul><ul><ul><li>from being uprooted crudely from nursery, </li></ul></ul><ul><ul><li>from being left in the sun to dry (dessicate), </li></ul></ul><ul><ul><li>from having soil knocked of the roots , </li></ul></ul><ul><ul><li>from being planted in hypoxic flooded soil </li></ul></ul><ul><li>reduces growth potential of the plants </li></ul><ul><li>Gentle, careful transplanting is crucial, not inverting the root tip upwards as this delays the resumption of growth </li></ul>
PHYLLOCHRONS <ul><li>were discovered in 1920s and 1930s by a Japanese scientist,T. Katayama </li></ul><ul><li>They are an interval of plant growth , found in all grass family grains (rice, wheat, etc.) – a repeating period in which one or more phytomers (units of a leaf, a root and a tiller) emerge from the apical meristem </li></ul><ul><li>Fr. de Laulanie came serendipitously upon the value of transplanting during the ‘window of opportunity’ during 2 nd or 3 rd phyllochron – to capitalize on the rice plant’s full potential </li></ul>
Effects of SRI vs. Conventional Practices Comparing Varietal and Soil Differences
Spread of SRI in Africa <ul><li>Madagascar : now 50,000-100,000 farmers, average about 6-8 t/ha, some double or more </li></ul><ul><li>Sierra Leone : 2.5 5.3 t/ha for 160 farmers </li></ul><ul><li>The Gambia : 2.5 7.4 t/ha for 10 farmers </li></ul><ul><li>Benin : 1.6 7.5 t/ha in controlled trial </li></ul><ul><li>Guinea : 2.5 9.4 t/ha (hybrid + SRI) </li></ul><ul><li>Mozambique: good soils 3 saline soils 3-8 t/ha </li></ul><ul><li>Senegal: 4-5 9-11 t/ha (FAO trials) </li></ul><ul><li>Interest in, but no results yet from: Ethiopia, Ghana, Mali, South Africa, Tanzania, and Uganda </li></ul>
Spread of SRI in Latin America <ul><li>Cuba : average 8-9 t/ha; INCA trial 12 t/ha; a number of farmers have reached 14 t/ha </li></ul><ul><li>Peru : initial problems with drought, frost; 2003 results 9-11 t/ha vs. current average of 6 t/ha ( not profitable given costs of production) </li></ul><ul><li>Interest in, but no results yet from: Barbados, Brazil, Colombia, Dominican Republic, Guyana, Haiti, Trinidad, and Venezuela </li></ul>