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0212 Opportunities for Rice Research and Production Deriving from the System of Rice Intensification (SRI) from Madagascar

0212 Opportunities for Rice Research and Production Deriving from the System of Rice Intensification (SRI) from Madagascar



Presenter: Norman Uphoff

Presenter: Norman Uphoff

Audience: International Rice Congress, Beijing

September 2002

Subject Country: General



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    0212 Opportunities for Rice Research and Production Deriving from the System of Rice Intensification (SRI) from Madagascar 0212 Opportunities for Rice Research and Production Deriving from the System of Rice Intensification (SRI) from Madagascar Presentation Transcript

    • Opportunities for Rice Research and Production Deriving from the System of Rice Intensification (SRI) from Madagascar Norman Uphoff Cornell International Institute for Food, Agriculture and Development
      • Something new , but only in part; much still to be demonstrated scientifically
      • A work in progress -- invite interest
      • SRI appears ‘too good to be true’ -- but increasing evidence it is ‘for real’
      • SRI is being used successfully by
        • a growing number of farmers in
        • a growing number of countries
      • rather than a “TECHNOLOGY”
      • Different paradigm for rice growing
      • though not entirely new; supported in literature
      • SRI is a set of PRINCIPLES
      • that are applied through a set of
      • PRACTICES that farmers are
      • expected to adapt to suit their
      • local conditions
    • Basic idea of SRI is that RICE PLANTS DO BEST
      • (A) When their ROOTS grow large and deep because they were
      • transplanted carefully , i.e., without trauma, and with
      • wide spacing between plants; and
      • (B) When they grow in SOIL that is:
      • well aerated with abundant and diverse
      • soil microbial populations
    • “ Starting Points” for SRI
      • Transplant young seedlings , 8-15 days,
      • quickly and very carefully
      • Single plants per hill with wide spacing in a square pattern, 25x25 cm or wider
      • No continuous flooding of field during the vegetative growth phase (AWD ok)
      • Use rotating hoe early and often (2-4x)
      • Application of compost is recommended
      • These produce a different PHENOTYPE
      • Average yields about 8 t/ha --
      • twice present world average of 3.8 t/ha
      • Maximum yields can be twice this -- about 16 t/ha, with a few over 20 t/ha
      • Water requirements reducible by 50%
      • Increased factor productivity for land, labor, capital and water --
      • Lowered costs of production per/kg MOST IMPORTANT FOR FARMERS
      • Changing varieties , though best yields from high-yielding varieties and hybrids ; traditional varieties produce very well
      • Chemical fertilizers -- these give very positive yield response with SRI, but compost gives best results
      • Agrochemicals – plants more resistant to pests and diseases with SRI methods
      • Seeding rate reduced as much as 90%, 5-10 kg/ha yields more than 50-100 kg
      • No lodging because of stronger roots
      • Environmentally friendly production due to water saving, no/fewer chemicals
      • More accessible to poor households because few capital requirements
      • SRI is more labor-intensive , at least initially -- but can become labor-saving ?
      • SRI requires greater knowledge/skill from farmers to become better decision-makers and managers -- but this contri-butes to human resource development
      • SRI requires good water control to get best results, making regular applications of smaller amounts of water -- this can be obtained through investments ?
      • LESS BECOMES MORE -- by utilizing the potentials and dynamics of biology
      • Smaller, younger seedlings will give larger, more productive mature plants
      • Fewer plants per hill and per m 2 can give more yield
      • Half the water can give higher yield
      • Fewer or no external inputs are associated with greater output
      • New phenotypes from existing genotypes
    • These are remarkable claims
      • But they reflect experience on farms, more than on experiment stations, and
      • They have some, if not yet complete, support in the scientific literature
      • I am not the originator of SRI, just a proponent for its being evaluated and used where appropriate, working with many colleagues around the world
      • SRI is the due entirely to the work of Fr. Henri de Laulanié, S.J . (1920-1995)
      • CIIFAD involvement with Tefy Saina began in 1994 around Ranomafana National Park in Madagascar, where yields averaged 2 t/ha
      • Previous work by NC State University: got average yield up to 3 t/ha, maximum of 5 t/ha
      • Tefy Saina helped farmers average 8 t/ha during 1994-1999, best yields up to 16 t/ha
      • Farmers in a French project improving small-scale irrigation on the high plateau had same results over same 5-year period
    • Spread beyond Madagascar
      • Nanjing Agricultural University - 1999
      • Agency for Agricultural Research and Development, Indonesia - 1999-2000
      • Philippines, Cambodia, Sri Lanka, etc.
      • China Hybrid Rice Center - 2000-2001
      • International conference, Sanya, China, April 2001 -- 15 countries represented
    • Participants at the SRI Conference in Sanya, China
    • Reports from Sanya Conference
    • SIX PROPOSITIONS SUGGESTED BY SRI [possible new paradigm]
      • (1) Rice is not an aquatic plant, or even hydrophilic
      • Although rice can survive under continuous flooding,
      • It does not thrive under these [suboptimal] conditions.
    • Evidence on Root System Development/Degeneration
      • Evaluated by ‘pull’ test of root resistance (O’Toole and Soemartono 1981)
      • Three plants [3-week seedlings, 3/hill, close planting, continuous flooding] averaged 28 kg/hill (Joelibarison 1998)
      • Single SRI plants [12-day seedlings, 1/hill, 25x25 cm, aerated soil] averaged 53 kg/hill -- resistance/plant > 5 times
    • Dry Matter Distribution of Roots in SRI and Conventionally-Grown Plants at Heading Stage (CNRRI research: Tao et al. 2002) Root dry weight (g)
    • 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
      • Need to understand PHYLLOCHRONS; related to leaf age or degree-days , but more precise and illuminating than ref. to “early, active, or maximum tillering...”
      • Discovered by Katayama (1920s-30s), further developed by de Laulanié (1993)
      • Under good growing conditions and if the root system is intact, the number of tillers per plant can exceed 100
    • What speeds up the biological clock? (adapted from Nemoto et al. 1995)
      • Shorter phyllochrons Longer phyllochrons
      • Higher temperatures > cold temperatures
      • Wider spacing > crowding of roots/canopy
      • More illumination > shading of plants
      • Ample nutrients in soil > nutrient deficits
      • Soil penetrability > compaction of soil
      • Sufficient moisture > drought conditions
      • Sufficient oxygen > hypoxic soil conditions
    • (3) Profuse tillering should not be considered unproductive
      • An inverse relationship has been reported in the literature between
      • the number of tillers/plant and
      • the number of grains/panicle
      • But this reflects the conventional
      • (hypoxic) growing environment of
      • rice plants, with root degeneration
    • With a large and intact root system and profuse tillering
      • the relationship is positive.
      • Increased grain filling
      • results from the
      • positive-sum dynamic
      • between the growth and vigor
      • of roots X tillers and leaves
    • This is what makes it possible to go from 2 t/ha to 8 t/ha
      • Synergistic relationships between root development and tillering -- each supports the other’s growth
      • Both together support increased grain filling
      • With good root development , 80% or more effective tillering, more filled grains and higher grain weight
    • (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
      • Creates demand for nutrients -- accelerating plant growth after first 5-6 weeks
      • Where does supply come from?
      • Probably need to consider biological processes and sources , not just current chemical availability
    • (6) The contributions of soil microbial activity should be considered more seriously
      • “ 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)
    • Biological Nitrogen Fixation?
      • BNF can occur with all gramineae species, including rice (Döbereiner 1987, and others)
      • In flooded paddies, BNF is limited to anaerobic processes; SRI provides aerobic conditions as well; BNF must be occurring
      • Mixing aerobic and anaerobic soil conditions increases BNF (Magdoff and Bouldin 1970)
      • Nitrogenase production is suppressed by the use of chemical fertilizers (van Berkum and Sloger 1983)
      • 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
      • “ Microbiological weathering” is probably more important than are the geochemical forms of weathering
      • Biological weathering processes are probably also increasing the availability of other nutrients such as S, Zn, etc.
    • MYCORRHIZAL Contributions?
      • Fungi cannot grow in anaerobic soil so flooded rice has forfeited the benefits of mycorrhizae for centuries
      • Mycorrhizal fungi can increase volume of soil accessed by root up to 100x
      • Plants with mycorrhizal associations can grow well with just a fraction of the P supply that “uninfected” plants need
    • Benefits from Rhizobia in rice now being explored
      • Studied where rice and clover grown in rotation in Egypt, for many centuries
      • These endophytic bacteria induce more efficient acquisition of N, P, K, Mg, Ca, Zn, etc. in rice (Yanni et al. 2001)
      • Rhizobia increase yield and total protein quantity/ha , by producing auxins and other plant-growth promoting hormones -- however, no BNF demonstrated
      • Farmers report that SRI practices “improve their soil quality” over time -- yields go up rather than down just by adding compost -- hard to explain
      • 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
    • Larger canopies and root systems increase exudation and rhizodeposition
      • 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)
      • Also 20% of plant N is transferred (Brimecombe et al. 2001)
      • Roots and shoots are “ two-way streets ”
      • But little known about exudation in rice (Wassmann and Aulakh 2000)
    • SRI Raises More Questions than It Gives ANSWERS
      • This is a PRACTICE-LED innovation
      • Scientists have a challenge/opportunity to develop and “retrofit” explanations
      • Phenotypical changes are the starting point -- these can surely be explained:
        • Greater root growth
        • Greater tillering
        • Less senescence of roots and canopy
        • Positive correlation: tillering x grain filling
    • Plant Physical Structure and Light Intensity Distribution at Heading Stage (CNRRI Research: Tao et al. 2002)
    • Suggested Focuses for Explanation of SRI Effects
      • Root development  different transplanting, wider spacing & soil aeration; roots ignored
      • Soil microbial abundance and activity  plant, soil, water & nutrient management, mixing aerobic / anaerobic conditions
      • SRI is a still “work in progress” invite interest & collaboration -- no IPR
      • SRI puts a presumed “ biological ceiling ” for rice in a different perspective
      • Fr. De Laulanié speculated that rice yields could even reach 30 t/ha when we fully utilize phyllochron dynamics
      • Exciting time to be a rice scientist!
      • More information is available
      • on the SRI WEB PAGE :
      • http://ciifad.cornell.edu/sri/
      • including Sanya conference proceedings
      • [email_address]
      • [email_address]
      • [email_address]