A Review of the System of Rice Intensification  (SRI)   Norman Uphoff  Cornell International Institute for Food, Agricultu...
SRI IS A  “WORK IN PROGRESS” <ul><li>Something new , but only in part; much still to be demonstrated scientifically </li><...
SRI  IS  A METHODOLOGY <ul><li>rather than a   “TECHNOLOGY”   </li></ul><ul><li>Different  paradigm  for rice growing </li...
The basic idea of SRI is that  RICE PLANTS GROW BEST <ul><li>(A) When plant  ROOTS  can grow very  large and deep  because...
“ Starting Points” for SRI <ul><li>Transplant   young seedlings ,   8-15 days, </li></ul><ul><li>quickly  and very   caref...
 
 
 
 
 
 
OBSERVABLE  RESULTS <ul><li>Average yields  about 8 t/ha  --  twice  the present world average of 3.8 t/ha </li></ul><ul><...
LESS OR NO NEED FOR: <ul><li>Different varieties , though best yields from  high-yielding varieties  and  hybrids;   tradi...
FURTHER  BENEFITS <ul><li>Seeding rate   reduced as much as 90%,  5-10 kg/ha yields more than 50-100 kg; </li></ul><ul><li...
DISADVANTAGES / COSTS <ul><li>SRI is more   labor-intensive ,   at least initially -- but can become  labor-saving ? </li>...
SRI is COUNTERINTUITIVE <ul><li>LESS BECOMES MORE   -- by utilizing the  potentials and dynamics of biology </li></ul><ul>...
These are remarkable claims <ul><li>But they reflect   experience on farms,   more than on experiment stations </li></ul><...
 
 
BACKGROUND <ul><li>CIIFAD   involvement with   Tefy Saina   began in 1994 around Ranomafana National Park in Madagascar, w...
 
Spread beyond Madagascar <ul><li>Nanjing Agricultural University - 1999 </li></ul><ul><li>Agency for Agricultural Research...
Participants at the SRI Conference in Sanya, China
Reports from Sanya Conference
SIX PROPOSED EXPLANATIONS <ul><li>(1) Rice is not an aquatic plant, or even hydrophilic </li></ul><ul><li>Although rice ca...
 
 
 
 
Evidence on Root System Development/Degeneration <ul><li>Evaluated by ‘pull’ test of root resistance (O’Toole and Soemarto...
Dry Matter Distribution of Roots in SRI and Conventionally-Grown Plants  at Heading Stage  (CNRRI research: Tao et al. 200...
Root Activity in SRI and Conventionally-Grown Rice (Nanjing Agr. Univ. research: Wang et al. 2002) (Wuxianggeng 9 variety)
 
(2) Tillering in rice is regulated by  structural  pattern of growth <ul><li>Understood in terms of   PHYLLOCHRONS   --   ...
 
 
 
What speeds up the biological clock?   (adapted from Nemoto et al. 1995) <ul><li>Shorter phyllochrons   Longer phyllochron...
 
 
(3) Profuse tillering should  not  be considered unproductive <ul><li>An   negative relationship   has been reported in th...
 
With a large and intact root system and profuse tillering <ul><li>this relationship is  positive.   </li></ul><ul><li>Incr...
 
This is what makes it possible to go from 2 t/ha to 8 t/ha <ul><li>A  synergistic relationship  between  root development ...
(4) Positive benefits are seen from  soil aeration  during the vegetative growth period
(5) SRI capitalizes on the fact that the  uptake of N  is a demand-led process
Paths for Increased Grain Yield in Relation to N Uptake, using QUEFTS Analytical Model  (Barison, 2002)
Rapid tillering and root growth <ul><li>Creates  demand  for nutrients --  accelerating  plant growth after  first 5-6 wee...
(6) The contributions of  soil microbial activity   are likely the foundation  for SRI success <ul><li>“ The microbial flo...
Biological Nitrogen Fixation? <ul><li>BNF  can occur with all gramineae species, including rice (Döbereiner 1987, and othe...
P SOLUBILIZATION? <ul><li>P solubilization  is increased under  alternating  aerobic and anaerobic soil conditions; Turner...
MYCORRHIZAL Contributions?   <ul><li>Fungi cannot grow in anaerobic soil  so flooded rice has forfeited the benefits of my...
Benefits from  Rhizobia   in rice now being explored <ul><li>Studied where rice and clover grown in rotation in Egypt, for...
ROOT EXUDATION <ul><li>Farmers report that SRI practices  “improve their soil quality”   over time  -- yields  go up  rath...
Larger canopies and root systems  increase exudation  and rhizodeposition <ul><li>30-60% of C fixed in canopy is sent to t...
SRI  Raises More Questions  than It Gives ANSWERS <ul><li>This is a   PRACTICE-LED  innovation </li></ul><ul><li>Scientist...
Plant Physical Structure and  Light Intensity Distribution  at Heading Stage   (CNRRI Research: Tao et al. 2002)
Suggested Focuses for Explanation of SRI Effects <ul><li>Root development  different transplanting, wider spacing & soil ...
MANY OPPORTUNITIES <ul><li>SRI is a still “work in progress”   invite interest & collaboration -- no IPR </li></ul><ul><li...
THANK YOU <ul><li>More information is available  </li></ul><ul><li>on the  SRI WEB PAGE : </li></ul><ul><li>http://ciifad....
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0210 A Review of the System of Rice Intensification (SRI)

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Mymensingh Workshop

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0210 A Review of the System of Rice Intensification (SRI)

  1. 1. A Review of the System of Rice Intensification (SRI) Norman Uphoff Cornell International Institute for Food, Agriculture and Development for presentation in Mymensingh, September 25, 2002
  2. 2. SRI IS A “WORK IN PROGRESS” <ul><li>Something new , but only in part; much still to be demonstrated scientifically </li></ul><ul><li>While SRI appears ‘too good to be true’ there is much evidence it is ‘for real’ </li></ul><ul><li>SRI is being used successfully by </li></ul><ul><ul><li>a growing number of farmers in </li></ul></ul><ul><ul><li>a growing number of countries (15+) </li></ul></ul>
  3. 3. SRI IS A METHODOLOGY <ul><li>rather than a “TECHNOLOGY” </li></ul><ul><li>Different paradigm for rice growing </li></ul><ul><li>Management produces a different phenotype </li></ul><ul><li>SRI is a set of PRINCIPLES </li></ul><ul><li>that are applied through a set of </li></ul><ul><li>PRACTICES that farmers are </li></ul><ul><li>expected to adapt to suit their </li></ul><ul><li>local conditions </li></ul>
  4. 4. The basic idea of SRI is that RICE PLANTS GROW BEST <ul><li>(A) When plant ROOTS can grow very large and deep because they have been </li></ul><ul><li>transplanted carefully , </li></ul><ul><li>i.e., without trauma, with optimally </li></ul><ul><li>wide spacing between plants </li></ul><ul><li>(B) And when rice is grown SOIL that is: </li></ul><ul><li>well aerated with abundant and diverse </li></ul><ul><li>soil microbial populations </li></ul>
  5. 5. “ Starting Points” for SRI <ul><li>Transplant young seedlings , 8-15 days, </li></ul><ul><li>quickly and very carefully </li></ul><ul><li>Single plants per hill with wide spacing in a square pattern, 25x25 cm or wider </li></ul><ul><li>No continuous flooding of field during the vegetative growth phase (AWD ok) </li></ul><ul><li>Use rotating hoe early and often (2-4x) </li></ul><ul><li>Recommend application of compost </li></ul><ul><li>Practices produce a different PHENOTYPE </li></ul>
  6. 12. OBSERVABLE RESULTS <ul><li>Average yields about 8 t/ha -- twice the present world average of 3.8 t/ha </li></ul><ul><li>Maximum yields can be twice this; about 16 t/ha, with some over 20 t/ha </li></ul><ul><li>Water requirements reducible by 50% </li></ul><ul><li>Increased factor productivity for land, labor, capital and water -- </li></ul><ul><li>MORE IMPORTANT THAN YIELD </li></ul><ul><li>Lower costs of production per/kg MOST IMPORTANT FOR FARMERS </li></ul>
  7. 13. LESS OR NO NEED FOR: <ul><li>Different varieties , though best yields from high-yielding varieties and hybrids; traditional varieties can yield very well </li></ul><ul><li>Chemical fertilizers -- while these give positive yield response with SRI, we find that compost gives best results </li></ul><ul><li>Agrochemicals – plants more resistant to pests and diseases with SRI methods so pesticides, etc. not often needed </li></ul>
  8. 14. FURTHER BENEFITS <ul><li>Seeding rate reduced as much as 90%, 5-10 kg/ha yields more than 50-100 kg; </li></ul><ul><li>smaller nursery area, less water needed </li></ul><ul><li>No lodging because of stronger roots </li></ul><ul><li>Environmentally friendly production due to water saving, no/fewer chemicals </li></ul><ul><li>More accessible to poor households because few capital requirements </li></ul>
  9. 15. DISADVANTAGES / COSTS <ul><li>SRI is more labor-intensive , at least initially -- but can become labor-saving ? </li></ul><ul><li>SRI requires greater knowledge/skill from farmers to become better decision-makers and managers -- but this is good for human resource development! </li></ul><ul><li>SRI requires good water control to get best results, making regular applications of smaller amounts of water -- but this can be obtained through investments ? Maybe not possible in monsoon climate </li></ul>
  10. 16. SRI is COUNTERINTUITIVE <ul><li>LESS BECOMES MORE -- by utilizing the potentials and dynamics of biology </li></ul><ul><li>Smaller, younger seedlings will give larger, more productive mature plants </li></ul><ul><li>Fewer plants per hill and per m 2 can give more yield </li></ul><ul><li>Half the water can give higher yield </li></ul><ul><li>Fewer or no external inputs are associated with greater output </li></ul><ul><li>New phenotypes from existing genotypes </li></ul>
  11. 17. These are remarkable claims <ul><li>But they reflect experience on farms, more than on experiment stations </li></ul><ul><li>They have some, if not yet complete, support in the scientific literature </li></ul><ul><li>Note: I am not the originator of SRI , just a proponent for its being evaluated and used where appropriate, now working with many colleagues around the world </li></ul><ul><li>SRI is the due entirely to the work of Fr. Henri de Laulanié, S.J . (1920-1995) </li></ul>
  12. 20. BACKGROUND <ul><li>CIIFAD involvement with Tefy Saina began in 1994 around Ranomafana National Park in Madagascar, where yields averaged 2 t/ha </li></ul><ul><li>Previous work by NC State University got average yield up to 3 t/ha, maximum of 5 t/ha </li></ul><ul><li>During 1994-99, Tefy Saina helped farmers average 8 t/ha , with best yields up to 16 t/ha </li></ul><ul><li>Over same period, farmers in French project improving small-scale irrigation on the high plateau had the same results </li></ul>
  13. 22. Spread beyond Madagascar <ul><li>Nanjing Agricultural University - 1999 </li></ul><ul><li>Agency for Agricultural Research and Development, Indonesia - 1999-2000 </li></ul><ul><li>Philippines, Cambodia, Bangladesh etc. </li></ul><ul><li>China Hybrid Rice Center - 2000-2001 </li></ul><ul><li>International conference, Sanya, China, April 2001 -- 15 countries represented </li></ul>
  14. 23. Participants at the SRI Conference in Sanya, China
  15. 24. Reports from Sanya Conference
  16. 25. SIX PROPOSED EXPLANATIONS <ul><li>(1) Rice is not an aquatic plant, or even hydrophilic </li></ul><ul><li>Although rice can survive under continuous flooding, </li></ul><ul><li>It does not thrive under these [suboptimal] conditions. </li></ul>
  17. 30. Evidence on Root System Development/Degeneration <ul><li>Evaluated by ‘pull’ test of root resistance (O’Toole and Soemartono 1981) </li></ul><ul><li>Three plants [3-week seedlings, 3/hill, close planting, continuous flooding] averaged 28 kg/hill (Joelibarison 1998) </li></ul><ul><li>Single SRI plants [12-day seedlings, 1/hill, 25x25 cm, aerated soil] averaged 53 kg/hill -- resistance/plant > 5 times </li></ul>
  18. 31. Dry Matter Distribution of Roots in SRI and Conventionally-Grown Plants at Heading Stage (CNRRI research: Tao et al. 2002) Root dry weight (g)
  19. 32. Root Activity in SRI and Conventionally-Grown Rice (Nanjing Agr. Univ. research: Wang et al. 2002) (Wuxianggeng 9 variety)
  20. 34. (2) Tillering in rice is regulated by structural pattern of growth <ul><li>Understood in terms of PHYLLOCHRONS -- related to leaf age or degree-days , but more precise and illuminating than ref. to “early, active, or maximum tillering...” </li></ul><ul><li>Discovered by Katayama (1920s-30s), further developed by de Laulanié (1993) </li></ul><ul><li>Under good growing conditions and if the root system is intact, the number of tillers per plant can exceed 100 </li></ul>
  21. 38. What speeds up the biological clock? (adapted from Nemoto et al. 1995) <ul><li>Shorter phyllochrons Longer phyllochrons </li></ul><ul><li>Higher temperatures > cold temperatures </li></ul><ul><li>Wider spacing > crowding of roots/canopy </li></ul><ul><li>More illumination > shading of plants </li></ul><ul><li>Nutrient supply in soil > nutrient deficits </li></ul><ul><li>Soil penetrability > compaction of soil </li></ul><ul><li>Sufficient moisture > drought conditions </li></ul><ul><li>Sufficient oxygen > hypoxic soil conditions </li></ul>
  22. 41. (3) Profuse tillering should not be considered unproductive <ul><li>An negative relationship has been reported in the literature between </li></ul><ul><li>the number of tillers/plant and </li></ul><ul><li>the number of grains/panicle </li></ul><ul><li>This, however, reflects conventional </li></ul><ul><li>hypoxic growing environments of </li></ul><ul><li>rice plants, with root degeneration </li></ul>
  23. 43. With a large and intact root system and profuse tillering <ul><li>this relationship is positive. </li></ul><ul><li>Increased grain filling </li></ul><ul><li>results from a </li></ul><ul><li>positive-sum dynamic </li></ul><ul><li>between the growth and vigor </li></ul><ul><li>of roots X tillers and leaves </li></ul>
  24. 45. This is what makes it possible to go from 2 t/ha to 8 t/ha <ul><li>A synergistic relationship between root development and tillering with each supporting the other’s growth </li></ul><ul><li>Then both together can support increased grain filling </li></ul><ul><li>With good root development , 80% or more effective tillering, more filled grains and higher grain weight </li></ul>
  25. 46. (4) Positive benefits are seen from soil aeration during the vegetative growth period
  26. 47. (5) SRI capitalizes on the fact that the uptake of N is a demand-led process
  27. 48. Paths for Increased Grain Yield in Relation to N Uptake, using QUEFTS Analytical Model (Barison, 2002)
  28. 49. Rapid tillering and root growth <ul><li>Creates demand for nutrients -- accelerating plant growth after first 5-6 weeks </li></ul><ul><li>Where does supply come from? </li></ul><ul><li>Probably attributable to biological processes and sources ; cannot be explained by “chemical” analyses </li></ul>
  29. 50. (6) The contributions of soil microbial activity are likely the foundation for SRI success <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>
  30. 51. Biological Nitrogen Fixation? <ul><li>BNF can occur with all gramineae species, including rice (Döbereiner 1987, and others) </li></ul><ul><li>In flooded paddies, BNF is limited to anaerobic processes; SRI provides aerobic conditions as well; BNF must be occurring </li></ul><ul><li>Mixing aerobic and anaerobic soil conditions increases BNF (Magdoff and Bouldin 1970) </li></ul><ul><li>Nitrogenase production is suppressed by the use of chemical fertilizers (van Berkum and Sloger 1983) </li></ul>
  31. 52. P SOLUBILIZATION? <ul><li>P solubilization is increased under alternating aerobic and anaerobic soil conditions; Turner and Haygarth (2001) measured large increases in soluble organic P with alternate wetting/drying </li></ul><ul><li>“ Microbiological weathering” is probably more important than are the geochemical forms of weathering </li></ul><ul><li>Biological weathering processes are probably also increasing the availability of other nutrients such as S, Zn, etc. </li></ul>
  32. 53. MYCORRHIZAL Contributions? <ul><li>Fungi cannot grow in anaerobic soil so flooded rice has forfeited the benefits of mycorrhizae for centuries </li></ul><ul><li>Mycorrhizal fungi can increase volume of soil accessed by root up to 100x </li></ul><ul><li>Plants with mycorrhizal associations can grow well with just a fraction of the P supply that “uninfected” plants need </li></ul>
  33. 54. Benefits from Rhizobia in rice now being explored <ul><li>Studied where rice and clover grown in rotation in Egypt, for many centuries </li></ul><ul><li>These endophytic bacteria induce more efficient acquisition of N, P, K, Mg, Ca, Zn, etc. in rice (Yanni et al. 2001) </li></ul><ul><li>Rhizobia increase yield and total protein quantity/ha , by producing auxins and other plant-growth promoting hormones -- however, no BNF demonstrated </li></ul>
  34. 55. ROOT EXUDATION <ul><li>Farmers report that SRI practices “improve their soil quality” over time -- yields go up rather than down just by adding compost -- hard to explain </li></ul><ul><li>The soils around Ranomafana were evaluated in chemical terms as some of the poorest in the world (Johnson 1994) e.g., 3-4 ppm P, low CEC all horizons </li></ul>
  35. 56. Larger canopies and root systems increase exudation and rhizodeposition <ul><li>30-60% of C fixed in canopy is sent to the roots, and 20-40% of this exuded or deposited in rhizosphere (Neumann and Römheld 2001, in Pinton et al. 2001) </li></ul><ul><li>Also 20% of plant N is transferred (Brimecombe et al. 2001) </li></ul><ul><li>Roots and shoots are “ two-way streets ” </li></ul><ul><li>However, little is known about exudation in rice (Wassmann and Aulakh 2000) </li></ul>
  36. 57. SRI Raises More Questions than It Gives ANSWERS <ul><li>This is a PRACTICE-LED innovation </li></ul><ul><li>Scientists have a challenge/opportunity to develop explanations for observed </li></ul><ul><li>phenotypical changes : </li></ul><ul><ul><li>Greater root growth </li></ul></ul><ul><ul><li>Greater tillering </li></ul></ul><ul><ul><li>Less senescence of roots and canopy </li></ul></ul><ul><ul><li>Positive correlation: tillering x grain filling </li></ul></ul>
  37. 58. Plant Physical Structure and Light Intensity Distribution at Heading Stage (CNRRI Research: Tao et al. 2002)
  38. 59. Suggested Focuses for Explanation of SRI Effects <ul><li>Root development  different transplanting, wider spacing & soil aeration; roots ignored </li></ul><ul><li>Soil microbial abundance and activity  plant, soil, water & nutrient management, mixing aerobic / anaerobic conditions </li></ul>
  39. 60. MANY OPPORTUNITIES <ul><li>SRI is a still “work in progress” invite interest & collaboration -- no IPR </li></ul><ul><li>SRI puts a presumed “ biological ceiling ” for rice in a different perspective </li></ul><ul><li>Fr. De Laulanié speculated that rice yields could even reach 30 t/ha when we fully utilize phyllochron dynamics </li></ul><ul><li>Exciting time to be a rice scientist! </li></ul>
  40. 61. THANK YOU <ul><li>More information is available </li></ul><ul><li>on the SRI WEB PAGE : </li></ul><ul><li>http://ciifad.cornell.edu/sri/ </li></ul><ul><li>including Sanya conference proceedings </li></ul><ul><li>E-MAIL ADDRESSES : </li></ul><ul><li>[email_address] </li></ul><ul><li>[email_address] </li></ul><ul><li>[email_address] </li></ul>

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