SRI SRI -- The System of -- The System of Rice Intensification: Rice Intensification:

An Opportunity for An Opportunity for Improving Food Security Improving Food Security

in Latin America?in Latin America?Presented at: 2nd International Rice Meeting, HavanaPresented at: 2nd International Rice Meeting, Havana

Norman UphoffNorman UphoffCornell International Institute for Food, Cornell International Institute for Food, Agriculture and Development (CIIFAD)Agriculture and Development (CIIFAD)

in cooperation with Association Tefy Saina (ATS)in cooperation with Association Tefy Saina (ATS)

More tillers and more than 400 grains per panicle

The The System of Rice System of Rice IntensificationIntensification (SIMA) developed (SIMA) developed in Madagascar almost 2 decades in Madagascar almost 2 decades ago can:ago can:

Increase rice production -- double yieldIncrease rice production -- double yield Improve food security esp. for poor HHs,Improve food security esp. for poor HHs, Raise total factor productivity, andRaise total factor productivity, and Enhance the environment -- cut demand Enhance the environment -- cut demand

for water by half, no use of for water by half, no use of agrochemicalsagrochemicals

Sounds too good to be Sounds too good to be truetrue

But SRI is being tried in But SRI is being tried in more and more and more countriesmore countries around world. around world.

The reasons for SRI performance can The reasons for SRI performance can be explained in be explained in scientific termsscientific terms..

It should be It should be put to empirical testsput to empirical tests, , not just rejected on not just rejected on a prioria priori grounds.grounds.

SRI is like the agronomists’ $100 bill SRI is like the agronomists’ $100 bill on the sidewalk.on the sidewalk.

SRI capitalizes on SRI capitalizes on potentialspotentials that have long existed in that have long existed in

the plant’s genetic the plant’s genetic endowmentendowment

These potentials These potentials have been have been inhibitedinhibited by the by the standard practicesstandard practices for growing irrigated rice.for growing irrigated rice.

SRI proposes SRI proposes managing plants, soil, managing plants, soil, water and nutrients water and nutrients in new waysin new ways..

These give us a different These give us a different phenotypephenotype from the existing rice genome.from the existing rice genome.

SRI gives an SRI gives an opportunityopportunity to to raiseraiseconcurrently the concurrently the productivityproductivity of:of: LandLand

LaborLabor CapitalCapital WaterWater

Not having to make Not having to make tradeoffstradeoffs among them among them

Also Also reduces farmers’reduces farmers’ costs of costs of productionproduction

SRISRI changes the wayschanges the ways that that farmers have grown irrigated rice farmers have grown irrigated rice for centuries, even millennia, for centuries, even millennia, using using simple methodssimple methods..

SRISRI is is more accessible to the more accessible to the poorpoor because it does not depend because it does not depend on external inputs -- it requires on external inputs -- it requires neither neither use of new seedsuse of new seeds nor nor application of agrochemicalsapplication of agrochemicals -- -- these are optional.these are optional.

SRISRI requires requires only about half as only about half as much water per seasonmuch water per season as when as when

rice is grown in continuously rice is grown in continuously flooded fieldsflooded fields

SRISRI may contribute also to may contribute also to reduction in greenhouse gas reduction in greenhouse gas emissionsemissions since rice grown in since rice grown in continuously flooded paddies continuously flooded paddies accounts for about 25% of accounts for about 25% of methanemethane (CH(CH44) going into atmosphere) going into atmosphere

SRI SRI is is COUNTERINTUITIVECOUNTERINTUITIVE,, because it enables us to getbecause it enables us to get

more from lessmore from less

Higher yieldsHigher yields result from: result from:

Transplanting Transplanting younger, smaller younger, smaller seedlingsseedlings

Fewer plantsFewer plants per hill & per m per hill & per m22

Using Using less waterless water per season, with per season, with

Less or no need for purchased inputsLess or no need for purchased inputs

There is There is mounting evidencemounting evidence from a from a growing number of countries that growing number of countries that SRI does indeed have the SRI does indeed have the potentialspotentials that were first reported from that were first reported from Madagascar -- now 15 countries. Madagascar -- now 15 countries.

Nobody is asked to accept and Nobody is asked to accept and utilize SRI based just on our reports utilize SRI based just on our reports -- --

Let it be Let it be tried and evaluated tried and evaluated by by both both farmers and researchersfarmers and researchers. .

Data from Sanya reportsData from Sanya reports

The main The main objectionsobjections against against this methodology have been this methodology have been that:that: SRI requires SRI requires good water managementgood water management SRI is SRI is labor-intensivelabor-intensive SRI appears SRI appears ““too good to be true”too good to be true”

(1) Water control is (1) Water control is definitely necessarydefinitely necessary(2) But SRI also gives (2) But SRI also gives higher returns to labor, higher returns to labor,

and over time, it can become and over time, it can become labor-savinglabor-saving(3) Appearing “too good to be true” only means (3) Appearing “too good to be true” only means

that SRI should be subjected to that SRI should be subjected to careful scrutinycareful scrutiny

In In MadagascarMadagascar, where yields average 2-2.5 , where yields average 2-2.5 t/ha, 100s of farmers in 2 programs (USAID t/ha, 100s of farmers in 2 programs (USAID and French) have averaged and French) have averaged 8-9 t/ha8-9 t/ha over a over a 5-year period -- on mostly very poor soils.5-year period -- on mostly very poor soils.

In In ChinaChina, the first , the first SRI trials at Nanjing SRI trials at Nanjing Agric. University Agric. University gave gave 9.2 to 10.5 9.2 to 10.5 t/hat/ha. While these . While these levels can be levels can be achieved in China achieved in China with the best with the best varieties and best varieties and best techniques, these techniques, these take take twice as much twice as much waterwater as applied as applied with SRI. with SRI.

SRI method used SRI method used with with hybrid rice hybrid rice varietiesvarieties has given has given yields in the yields in the 12-15 12-15 t/hat/ha range. range.

In In CambodiaCambodia andand MyanmarMyanmar, where , where conventional yields are even lower than in conventional yields are even lower than in Madagascar (2 t/ha), farmers using SRI have Madagascar (2 t/ha), farmers using SRI have averaged averaged 5-6 t/ha5-6 t/ha with NGO guidance. with NGO guidance.

In In Sri LankaSri Lanka, where the average yield is , where the average yield is about 3.5 t/ha, farmers have averaged about 3.5 t/ha, farmers have averaged ~8 ~8 t/hat/ha with SRI, with some farmers achieving with SRI, with some farmers achieving much higher yields.much higher yields.

In In Sri Lanka and MadagascarSri Lanka and Madagascar, some , some farmers are getting yields in the range of farmers are getting yields in the range of 15 15 to 20 t/hato 20 t/ha once they have mastered the once they have mastered the techniques and improved their soil quality. techniques and improved their soil quality. The maximum potential of SRI methodology The maximum potential of SRI methodology remains to be fully realized.remains to be fully realized.

SRI effectsSRI effects are seen with are seen with all varieties,all varieties, both traditional and high-yielding.both traditional and high-yielding.

Good newsGood news for rice breeders is that very for rice breeders is that very best results have come with best results have come with use of use of HYVsHYVs, e.g., IR15 (11-12 t/ha), IR46 (13.5 , e.g., IR15 (11-12 t/ha), IR46 (13.5 t/ha), BG235 (17 t/ha), Tainung 16 (21 t/ha), BG235 (17 t/ha), Tainung 16 (21 t/ha)t/ha)

SRI is essentially SRI is essentially a set of a set of insights insights and and principlesprinciples about about how to help rice plantshow to help rice plants achieve more productive phenotypesachieve more productive phenotypes by by realizing genetic potentials in the plant. realizing genetic potentials in the plant.

The basic The basic PRINCIPLESPRINCIPLESunderlying SRI are: underlying SRI are:

(A) RICE (A) RICE PLANTSPLANTS WILL PERFORM WILL PERFORM BETTER WITH:BETTER WITH:

Careful transplantingCareful transplanting,, to minimize to minimize trauma, trauma, Wide spacingWide spacing,, for canopy and root growth, offor canopy and root growth, of Young seedlingsYoung seedlings (before 4th phyllochron) so (before 4th phyllochron) so

rice plants’ rice plants’ growth potential will be preserved.growth potential will be preserved.

(B) RICE WILL PERFORM (B) RICE WILL PERFORM BETTER IN BETTER IN SOILSOIL that is:that is:

Well-aeratedWell-aerated during the vegetative during the vegetative growth period, through:growth period, through:* careful water management, and* mechanical weeding (rotating hoe).

Enriched microbiologically through * compost (SOM), and different (SRI)* plant/soil/water/nutrient management.

SRI SRI PRACTICESPRACTICES – to be varied – to be varied according to local conditions are:according to local conditions are:

Early transplantingEarly transplanting -- < 15 days, best -- < 15 days, best between 8-12 days, only two tiny leavesbetween 8-12 days, only two tiny leaves

Careful transplantingCareful transplanting – in 15-30 min., – in 15-30 min., root laid into soil 1-2 cm, shaped like L root laid into soil 1-2 cm, shaped like L > J> J

Wide spacingWide spacing – – single plantssingle plants per hill, per hill, in a in a square patternsquare pattern,, 25x25cm, up to 25x25cm, up to 50x50cm50x50cm

SRI PracticesSRI Practices (continued) (continued) Well-drained soilWell-drained soil during vegetative growth during vegetative growth

phase – phase – with with no continuously standing waterno continuously standing water – – either by (a) daily application of small either by (a) daily application of small

amounts, or (b) alternate wetting and drying amounts, or (b) alternate wetting and drying (4-5 days) (4-5 days)

After PI, keep a After PI, keep a thin layer of waterthin layer of water (1-2 cm); (1-2 cm); and then drain ~15 days before harvestingand then drain ~15 days before harvesting

Early and frequent weedingEarly and frequent weeding, , start 10-12 start 10-12 DAT; up to 4 times, using a “rotating hoe”DAT; up to 4 times, using a “rotating hoe”

Nutrient amendmentsNutrient amendments are recommended – are recommended – with with compostcompost preferred over chemical fertilizer, preferred over chemical fertilizer, best applied to the best applied to the preceding croppreceding crop

.

RESULTSRESULTS of SRI Practices of SRI Practices

These practices lead to These practices lead to synergisticsynergistic

(a) (a) Root developmentRoot development with with increasedincreased

(b) (b) Increased tillering,Increased tillering, supporting supporting

(c) (c) Greater grain filling.Greater grain filling.

There appears also to be greaterThere appears also to be greater

(d) (d) Resistance to pests and diseasesResistance to pests and diseases

OBSERVABLE OBSERVABLE PHENOTYPICAL CHANGES PHENOTYPICAL CHANGES

attributable to SRIattributable to SRI More tillers/plantMore tillers/plant -- 30-50, even 100+-- 30-50, even 100+ Larger root systemsLarger root systems – – root pulling root pulling

resistanceresistance of of 28 kg28 kg/clump for /clump for 33 plantsplants grown conventionally vs. grown conventionally vs. 53 kg53 kg/plant /plant for for singlesingle SRI plants -- >5x per plant SRI plants -- >5x per plant

Positive correlationPositive correlation tillers/plant and tillers/plant and grains/panicle – no lodginggrains/panicle – no lodging

Comparison of high-yield rice in Comparison of high-yield rice in tropical and subtropical environments: tropical and subtropical environments: I: Determinants of grain and dry matter I: Determinants of grain and dry matter

yieldsyieldsJ. Ying, S. Peng, Q. He, H. Yang, C. J. Ying, S. Peng, Q. He, H. Yang, C.

Yang, R. M. Visperas, K. G. Cassman, Yang, R. M. Visperas, K. G. Cassman, Field Crops ResearchField Crops Research, 57 (1998), p. 72., 57 (1998), p. 72.

“…“…a a strongstrong compensation mechanism compensation mechanism exists between the two yield exists between the two yield components [panicle number and components [panicle number and panicle size]” with a “panicle size]” with a “strongstrong negative negative relationship between the two relationship between the two components…” (emphasis added)components…” (emphasis added)

Rice is Rice is not an aquatic not an aquatic plantplant

The standard understanding of rice is that:The standard understanding of rice is that: ““Rice Rice thrivesthrives on land that is water- on land that is water-

saturated or even submerged during part saturated or even submerged during part or all of its growth cycle.” (p. 43)or all of its growth cycle.” (p. 43)

““Most varieties maintain Most varieties maintain better growthbetter growth and and produce higher grain yieldsproduce higher grain yields when when grown in flooded soil than when grown in grown in flooded soil than when grown in unflooded soil.” (pp. 297-298).unflooded soil.” (pp. 297-298).

S. K. DeDatta, S. K. DeDatta, The Principles and Practices The Principles and Practices of Rice Productionof Rice Production, J. W. Wiley, NY, 1981. , J. W. Wiley, NY, 1981.

But in flooded (hypoxic) soil, rice roots But in flooded (hypoxic) soil, rice roots remainremain close to the surface. At 29 DAT, about close to the surface. At 29 DAT, about ¾ ¾ are inare in top 6 cm top 6 cm of soil (Kirk and Solivas 1997)of soil (Kirk and Solivas 1997) Rice plant roots grown in flooded soil form Rice plant roots grown in flooded soil form

aerenchymaaerenchyma (air pockets) through (air pockets) through disintegration of the cortexdisintegration of the cortex which is “often which is “often almost total…[after PI] the main body of the almost total…[after PI] the main body of the root system is largely degraded and seems root system is largely degraded and seems unlikely to be very active in nutrient unlikely to be very active in nutrient uptake” (Kirk and Bouldin 1991)uptake” (Kirk and Bouldin 1991)

Yet in unflooded soil Yet in unflooded soil neitherneither irrigated nor irrigated nor upland varieties form upland varieties form aerenchymaaerenchyma (Puard et (Puard et al. 1989) al. 1989)

Root cross-sections for Root cross-sections for upland (left) and irrigated (right) varieties -- upland (left) and irrigated (right) varieties --

ORSTOM research by Puard et al. (1989) ORSTOM research by Puard et al. (1989)

AbstractAbstractNature and growth pattern of rice root system Nature and growth pattern of rice root system

under submerged and unsaturated conditionsunder submerged and unsaturated conditionsS. Kar, S. B. Varade, T. K. Subramanyam, and B. P. Ghildyal,S. Kar, S. B. Varade, T. K. Subramanyam, and B. P. Ghildyal,

Il RisoIl Riso (Italy), 1974, 23:2, 173-179 (Italy), 1974, 23:2, 173-179Plants of the rice cultivar Taichung (Native) were grown Plants of the rice cultivar Taichung (Native) were grown

in pots of sandy loam under 2 water regimes in an in pots of sandy loam under 2 water regimes in an attempt to identify critical root-growth phases. attempt to identify critical root-growth phases. Observations on root number, length, volume and dry Observations on root number, length, volume and dry weight were made at early tillering, active tillering, weight were made at early tillering, active tillering, maximum tillering, and reproductive stages.maximum tillering, and reproductive stages.

Rice root degenerationRice root degeneration, , normally unique to submerged normally unique to submerged conditionsconditions, increased with advance in plant growth. , increased with advance in plant growth. At flowering,At flowering, 78%78% had degeneratedhad degenerated. During the first . During the first phase under flooding, and phase under flooding, and throughout the growth throughout the growth period under unsaturated conditions,period under unsaturated conditions, roots rarely roots rarely degenerated.degenerated.

Explanation of Explanation of tiller and root tiller and root growthgrowth in terms of in terms of

phyllochronsphyllochrons These are periodic These are periodic intervals of plant growthintervals of plant growth

common to all the common to all the gramineaegramineae species -- in rice, species -- in rice, a a phyllochronphyllochron is usually from ~5-8 days is usually from ~5-8 days

During each During each phyllochronphyllochron, the plant produces , the plant produces from its apical meristem from its apical meristem 1 or more1 or more phytomersphytomers (phytomer = a unit of a tiller, a leaf and a root)(phytomer = a unit of a tiller, a leaf and a root)

PhyllochronsPhyllochrons represent represent biological rather than biological rather than calendar time calendar time –– they are lengthened/shortened they are lengthened/shortened by a number of factors that can by a number of factors that can slow down slow down oror speed upspeed up the plant’s the plant’s “biological clock”“biological clock”

Speeding up the biological Speeding up the biological clockclock

Higher Higher temperaturetemperature vs. vs. cold cold temperaturestemperatures Wider Wider spacingspacing vs. root/canopy vs. root/canopy crowdingcrowding More More solar radiationsolar radiation vs. vs. shadeshade Ample Ample nutrientsnutrients in soil vs. in soil vs. nutrient nutrient

deficitsdeficits Soil Soil penetrabilitypenetrability vs. soil vs. soil compactioncompaction Sufficient Sufficient moisturemoisture vs. vs. droughtdrought conditions conditions Sufficient Sufficient oxygenoxygen vs. vs. hypoxic hypoxic conditionsconditions

Evidence of Evidence of SynergySynergy

Factorial trials by Faculty of Agriculture Factorial trials by Faculty of Agriculture students at Univ. of Antananarivo, under students at Univ. of Antananarivo, under contrasting agroecological conditionscontrasting agroecological conditions::

West coast near Morondava, 2000: West coast near Morondava, 2000:

hot, dry climate, poor sandy soils, hot, dry climate, poor sandy soils, ~100m~100m

High plateau at Anjomakely, 2001: High plateau at Anjomakely, 2001:

temperate climate, better soils, temperate climate, better soils, ~1200m~1200m

Evaluating Six FactorsEvaluating Six Factors

Variety:Variety: HYV (2798) vs. local (riz rouge) HYV (2798) vs. local (riz rouge) oror Soil quality:Soil quality: clay (better) vs. loam (poor) clay (better) vs. loam (poor)

Water mgmt:Water mgmt: aeratedaerated vs. saturated soil vs. saturated soil Seedling age:Seedling age: 8 days8 days vs. 16 or 20 days vs. 16 or 20 days Plants per hill:Plants per hill: 1/hill1/hill vs. 3/hill vs. 3/hill Fertilization:Fertilization: compostcompost vs. NPK vs. none vs. NPK vs. none Spacing:Spacing: 25x25cm vs. 30x30cm (NS diff.) 25x25cm vs. 30x30cm (NS diff.)

6 replications:6 replications: 2.5x2.5m plots (N=288, 240) 2.5x2.5m plots (N=288, 240)

Value of Value of Soil AerationSoil Aeration??

Data from 76 farmers at Ambatovaky, Data from 76 farmers at Ambatovaky, 1997-98 season1997-98 season

Yield differentials analyzed according to Yield differentials analyzed according to number of weedingsnumber of weedings with “rotary hoe” with “rotary hoe”

Similar effect of weeding in data from Similar effect of weeding in data from thesis by Frederic Bonlieu (Univ of Anjers)thesis by Frederic Bonlieu (Univ of Anjers)

1 weeding = 4.2 t/ha, 2 weedings – 4.4 t/ha1 weeding = 4.2 t/ha, 2 weedings – 4.4 t/ha3 weedings = 5.1 t/ha ($20 yields $210?)3 weedings = 5.1 t/ha ($20 yields $210?)

Emergent Concerns from Emergent Concerns from SRISRI

Importance of Importance of ROOTSROOTSDeDatta book on rice (1981): in chapter on the DeDatta book on rice (1981): in chapter on the “morphology, growth and development of the “morphology, growth and development of the rice plant”rice plant” -- only -- only 88 out of 390out of 390 lines of text on lines of text on roots, and in 16-page roots, and in 16-page indexindex with 1,100 entries, with 1,100 entries,

not even not even oneone entry entry on roots – “roots a waste”? on roots – “roots a waste”? Importance of Importance of SOIL MICROBIOLOGYSOIL MICROBIOLOGY

-- presently ignoring exudates, mycorrhizae, -- presently ignoring exudates, mycorrhizae, etc.etc.

Root ExudationRoot Exudation

““The amount of knowledge available on The amount of knowledge available on exudation from rice plantsexudation from rice plants is minuteis minute…” …” (Wassman and Aulakh, 2000)(Wassman and Aulakh, 2000)

Maize grown in a nutrient culture Maize grown in a nutrient culture solution exuded solution exuded three times lower three times lower amount amount of sugars and vitamins than of sugars and vitamins than exudation by plants grown in a solid exudation by plants grown in a solid substrate (Schönwitz and Ziegler, 1982)substrate (Schönwitz and Ziegler, 1982)

Root Exudation Root Exudation (cont’d)(cont’d) Exudation can cope with nutrient Exudation can cope with nutrient

deficiencies through deficiencies through mobilization of mobilization of nutrientsnutrients at the root-soil interface at the root-soil interface (Nagarajah et al., 1970)(Nagarajah et al., 1970)

Plants not only adjust the Plants not only adjust the quantityquantity but but also the also the qualityquality of root exudates, e.g., in of root exudates, e.g., in the response to the response to deficiencies of Mn and deficiencies of Mn and FeFe, and in the , and in the secretion of nitrogenasesecretion of nitrogenase (Wassmann and Aulakh, 2000)(Wassmann and Aulakh, 2000)

Root ExudationRoot Exudation (cont’d) (cont’d) Plants under stressPlants under stress commonly commonly increaseincrease

their exudation rather than decrease it -- their exudation rather than decrease it -- against usual expectations (Shigo, 2000)against usual expectations (Shigo, 2000)

Nutrients transported in the phloem are Nutrients transported in the phloem are not just stored in plant organsnot just stored in plant organs but are but are given upgiven up into the rhizosphere. into the rhizosphere.

Plants should be understood as Plants should be understood as “two-way” “two-way” streets,”streets,” not “one-way” streets concerned not “one-way” streets concerned only with only with uptakeuptake of of water and nutrientswater and nutrients..

Importance of Importance of MicroorganismsMicroorganisms

““The main biochemical processes in The main biochemical processes in flooded soil can be regarded as a series flooded soil can be regarded as a series of successive oxidation-reduction of successive oxidation-reduction reactions mediated by bacteria…reactions mediated by bacteria…

““The microbial flora cause a large The microbial flora cause a large number of biochemical changes in the number of biochemical changes in the soil that soil that largely determinelargely determine the fertility the fertility of the soil.of the soil.” (De Datta, 1981, p. 60, ” (De Datta, 1981, p. 60, emphasis added)emphasis added)

Uptake of N is Uptake of N is Demand-Demand-DrivenDriven

The The rate of uptake of Nrate of uptake of N by rice roots is by rice roots is independentindependent of the of the concentration of Nconcentration of N at at the roots’ surfacethe roots’ surface (Kirk and (Kirk and Bouldin,1991).Bouldin,1991).

Rice roots ‘down-regulate’ their transport Rice roots ‘down-regulate’ their transport system for NHsystem for NH4+4+ influx and/or ‘up- influx and/or ‘up-regulate’ the efflux, thereby regulate’ the efflux, thereby exuding exuding ammonium ammonium in excess of plant needsin excess of plant needs (Ladha et al., 1998, emphases added).(Ladha et al., 1998, emphases added).

Alternative Models for N Alternative Models for N UptakeUptake

Supply-Side Model Supply-Side Model to Increase Growth to Increase Growth

Apply N to the soilApply N to the soil to raise N to raise N availabilityavailability

This assumes that rice This assumes that rice plants will take up more plants will take up more N if it is N if it is easier for them easier for them to access Nto access N because of because of higher concentrationshigher concentrations in the root zonein the root zone

Demand-Driven Model Demand-Driven Model for Promoting Growthfor Promoting Growth

Manage plantsManage plants in in ways that ways that accelerateaccelerate their their rate of growthrate of growth

This reflects an under-This reflects an under-standing that standing that increased increased plantplant demanddemand for N for N is is whatwhat induces the rootsinduces the roots to take up more Nto take up more N

OBJECTIONS to SRIOBJECTIONS to SRI Slow Spread in MadagascarSlow Spread in Madagascar -- true, but now -- true, but now

changing with CRS and government supportchanging with CRS and government support Data from French irrigation project around Data from French irrigation project around

Antsirabe and Ambositra for period from Antsirabe and Ambositra for period from 1994/95 to 1998/99 (Hirsch, 2000)1994/95 to 1998/99 (Hirsch, 2000)

SRISRI area expandedarea expanded from from 34.5 to 532.8 ha34.5 to 532.8 ha, , without an active extension programwithout an active extension program

SRISRI yieldsyields averagedaveraged 7.91-9.12 t/ha7.91-9.12 t/ha vs. vs. 3.58-3.95 t/ha3.58-3.95 t/ha with recommended package with recommended package 2.24-2.47 t/ha2.24-2.47 t/ha with peasant practices with peasant practices

Difficulty in Replicating Difficulty in Replicating ResultsResults

SRI has been one of the few agricultural SRI has been one of the few agricultural innovations where innovations where farmers have often farmers have often gotten higher yields than researchersgotten higher yields than researchers

Usually it is the Usually it is the reverse,reverse, that that researchers’ results are difficult to researchers’ results are difficult to replicate on farmers’ fields -- farmers replicate on farmers’ fields -- farmers do better with SRI.do better with SRI.

Possible explanations may be found in Possible explanations may be found in evaluations of evaluations of soil microbiology.soil microbiology.

SRI is SRI is Labor-IntensiveLabor-Intensive

SRI does require 25-50% SRI does require 25-50% more labor inputsmore labor inputs, , at least at least initiallyinitially -- one study in Madagascar -- one study in Madagascar with 109 farmers found a with 109 farmers found a 26% difference;26% difference; Sri Lankan analysis found an Sri Lankan analysis found an 11% difference11% difference

But SRI time required is But SRI time required is reducedreduced as farmers as farmers gain skill and confidence; almost alwaysgain skill and confidence; almost always the the returns to labor are higher by 25-50%returns to labor are higher by 25-50%

Some farmers who have mastered SRI Some farmers who have mastered SRI techniques report that they are techniques report that they are labor-savinglabor-saving

If farmers are If farmers are labor-constrainedlabor-constrained, , it is it is most beneficial most beneficial

economicallyeconomically for them to for them to use SRIuse SRI on as much of their land as they on as much of their land as they

have enough labor forhave enough labor for, to , to capture higher returns to all capture higher returns to all

their factors of production (land, their factors of production (land, labor, capital, water), and then labor, capital, water), and then toto useuse remaining land for remaining land for other other

purposespurposes

SRI is SRI is Skill-IntensiveSkill-Intensive

Yes, this can be seen as Yes, this can be seen as a positive a positive featurefeature, rather than as , rather than as something something negativenegative -- since it is a -- since it is a BENEFITBENEFIT as as well as a well as a COSTCOST

Farmers involved in SRI evaluation and Farmers involved in SRI evaluation and adaptation learn to become adaptation learn to become more more experimental and more innovativeexperimental and more innovative

Being rewarded for unlearning old ways Being rewarded for unlearning old ways opens up opens up new avenues for developmentnew avenues for development

SRI is about SRI is about HUMAN HUMAN RESOURCE RESOURCE

DEVELOPMENTDEVELOPMENT

Not just about Not just about MORE MORE PRODUCTION OF RICEPRODUCTION OF RICE

SRI Needs SRI Needs Better Water Better Water ControlControl

This is the This is the main requirement and limitationmain requirement and limitation There will be There will be many areasmany areas where SRI cannot where SRI cannot

be be presentlypresently utilized for this reason utilized for this reason But the greatly But the greatly increased factor productivity increased factor productivity

with SRI should make new with SRI should make new investmentsinvestments in in water control infrastructurewater control infrastructure profitable profitable

This kind of investment should This kind of investment should attract donorsattract donors that are interested in that are interested in food security, poverty food security, poverty reduction, and environmental benefitsreduction, and environmental benefits

There is There is Not Enough Not Enough CompostCompost??

But compost is an But compost is an acceleratoraccelerator, not a , not a requirementrequirement

Most farmers in Madagascar with Most farmers in Madagascar with doubled doubled yieldsyields are are not using compostnot using compost -- or NPK-- or NPK

Most who get Most who get tripled yields or moretripled yields or more are using are using compostcompost

If yields can be increased 2-3x, the If yields can be increased 2-3x, the returns to returns to laborlabor from making and applying compost can from making and applying compost can justify growing biomass and harvesting itjustify growing biomass and harvesting it from from non-arable land areasnon-arable land areas

SRI is SRI is Only Good on Small Only Good on Small ScaleScale

Not a valid objectionNot a valid objection if if poverty reductionpoverty reduction is is an objectivean objective

There are There are many millions of small and poor many millions of small and poor farmersfarmers with only 0.25-1.0 hectare of land with only 0.25-1.0 hectare of land

SRI can be scaled up:SRI can be scaled up: one early adopter has one early adopter has gone from 0.25 to 8.0 hectares -- now richgone from 0.25 to 8.0 hectares -- now rich

SRI methods can be adaptedSRI methods can be adapted to larger scale to larger scale once the scientific principles are understood; once the scientific principles are understood; SRI is not a fixed or finished technologySRI is not a fixed or finished technology

If SRI is So Good, Why If SRI is So Good, Why Wasn’t SRI Discovered Wasn’t SRI Discovered

Before?Before? Each of the main practices Each of the main practices looks riskylooks risky If a farmer’s family depends on rice harvest:If a farmer’s family depends on rice harvest: Why plant Why plant a tiny seedlinga tiny seedling, not larger one?, not larger one? Why plant Why plant only one per hillonly one per hill, and not more?, and not more? Why plant just Why plant just a few plantsa few plants per m per m2 2 ?? Why not provide the rice plants with Why not provide the rice plants with

as much water as possible?as much water as possible? Makes no Makes no sensesense

SRI fields look SRI fields look terribleterrible for first 4-5 weeks for first 4-5 weeks

Practices seem Practices seem risky, even risky, even crazycrazy

The The chanceschances of someone doing of someone doing all of these all of these togethertogether, at the same time, are , at the same time, are negligiblenegligible

Actually, some SRI practices such as Actually, some SRI practices such as single plants, well-drained soil, and use of single plants, well-drained soil, and use of compost have been compost have been traditionallytraditionally used by used by farmersfarmers

But But active soil aerationactive soil aeration with with promotion of promotion of microbial activitymicrobial activity needed the needed the rotating hoerotating hoe

However, this was used for However, this was used for row plantingrow planting, , which maintains relatively which maintains relatively dense spacingdense spacing

SRI is Still a SRI is Still a “Work in “Work in Progress”Progress”

We We invite othersinvite others to join in experimenting to join in experimenting with and evaluating these methods.with and evaluating these methods.

Scientific investigationsScientific investigations and and practical practical trialstrials by farmers should by farmers should proceed in proceed in parallel,parallel, with with each contributing to the each contributing to the otherother..

ImplicationsImplications of SRI of SRI insights and practicesinsights and practices should be considered should be considered for for other cropsother crops and and for agriculture in generalfor agriculture in general..