Potential Contributions of the System of Rice Intensification

to Balancing Food and Environmental Security -- with

Agricultural Diversification

2nd International Agronomy Congress, New Delhi, November 26-30, 2002

Norman Uphoff,Cornell International Institute for

Food, Agriculture and Development

More tillers and more than 400 grains per panicle

SRI is something quite remarkable and promising but still “a work in progress”

• SRI appears ‘too good to be true’ like the agronomists’ equivalent of economists’ $100 bill on the sidewalk

• However there is increasing evidence that this system is ‘for real’

• SRI is being used successfully by – a growing number of farmers in – a growing number of countries (16+)

SRI IS A METHODOLOGY rather than a “TECHNOLOGY”

Different paradigm for growing rice that can be justified from the literature

SRI is really a set of PRINCIPLESand INSIGHTS that get applied

through a set of PRACTICES that farmers are encouraged to adapt

to suit their local conditions

The basic idea of SRI is that RICE PLANTS DO BEST

(A) When their ROOTS can grow large and deep because they have been

• transplanted carefully, without trauma, and there is• wide spacing between plants; also

(B) When they grow in SOIL that is kept• well aerated, with abundant and diverse• soil microbial populations

“Starting Points” for SRI• Transplant young seedlings, 8-15 days

(2 leaves) -- 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)

• Weeding with rotating hoe early (10 DAT) and often -- 2 to 4 times

• Application of compost is recommended

These practices produce a different PHENOTYPE

• Profuse TILLERING -- 30 to 50/plant, 80-100 possible, sometimes 100+

• Greater ROOT GROWTH -- 5-6x more resistance (kg/plant) for uprooting

• Larger PANICLES -- 150-250+ grains

• Higher GRAIN WEIGHT -- often 5-10%

• A POSITIVE CORRELATION between tillers/plant and grains/panicle

• LESS SENESCENCE of leaves/roots

Plant Physical Structure and Light Intensity Distribution

at Heading Stage (CNRRI Research: Tao et al. 2002)

Comparison of highComparison of high--yield rice in tropical and yield rice in tropical and subtropical environments: I: Determinants of subtropical environments: I: Determinants of

grain and dry matter yieldsgrain and dry matter yieldsJ . Ying, S. J . Ying, S. PengPeng, Q. He, H. Yang, C. Yang, , Q. He, H. Yang, C. Yang,

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

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

OBSERVABLE BENEFITS• Average yields about 8 t/ha --

twice present world average of 3.8 t/ha

• Maximum yields can be twice this -- 15-16 t/ha, with some over 20 t/ha

• Water required reducible by about 50%

• Increased factor productivity from land, labor, capital and water ( > yield)

• Lower costs of production -- this is often most important to farmers

LESS OR NO NEED FOR:• Changing varieties, though best yields

from high-yielding varieties and hybrids -- traditional varieties produce 4-10 t/ha

• Chemical fertilizers -- these give a very positive yield response with SRI, but best results are obtained with compost

• Agrochemicals – plants more resistant to pests and diseases with SRI methods

ADDITIONAL BENEFITS• Seeding rate reduced as much as 90%,

5-10 kg/ha gives 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

• Can be more drought-resistant

Analysis of SRI in Sri Lanka SRI Standard

• Yields (tons/ha) 8 4 +88%

• Market price (Rs/ton) 1,500 1,300 +15%

• Total cash cost (Rs/ha) 18,000 22,000 -18%

• Gross returns (Rs/ha) 120,000 58,500 +74%

• Net profit (Rs/ha) 102,000 36,500 +180%

• Family labor earnings Increased with SRI

• Water savings 40-50%

Data from Dr. Janaiah Aldas, formerly economist at IRRI, now at Indira Gandhi Development Studies Institute, Mumbai, based on visit to Sri Lanka and interviews with SRI farmers, October, 2002

DISADVANTAGES / COSTS• 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

SRI is COUNTERINTUITIVE• LESS CAN BCOME MORE -- utilizing

the potentials and dynamics of biology• Smaller, younger seedlings will give

larger, more productive mature plants• Fewer plants per hill and per m2 can give

more yield with other conditions• Half the water can give a higher yield• Fewer or no external inputs are

associated with greater outputNew phenotypes from existing genotypes

These results more often come from farms than experiment stations

• Though increasing number of scientists working on SRI -- NAU, AARD, TNAU, CNHRRDC, CNRRI, BRRI, Cuban IRR

• SRI is the due entirely to the work of Fr. Henri de Laulanié, S.J.(1920-1995), trained in agriculture at INA (1937-1939)

• He lived and worked with farmers in Madagascar, 1961-1995, SRI from 1983

• SRI now being promoted by NGO named Association Tefy Saina, assisted by CIIFAD

Initial Experience with SRI• Average yields of irrigated rice with standard

methods around Ranomafana National Park were about 2 t/ha in 1990 -- very low

• NC State University working with farmers got average yield of 3 t/ha, max. of 5 t/ha

• We would have been satisfied with an increase up to 3-5 t/ha -- a doubling of yield

• Tefy Saina helped farmers average 8 t/ha over 1994-1999 period, some yields 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

Reports from Sanya ConferenceCOUNTRY No. of Data

Sets/Trials(No. of farmers)

Ave. SRIYield (t/ha)

ComparisonYield (t/ha)

Max. SRIYields (t/ha)

Bangladesh 4 On-farm (261)6 On-station

6.35.25-7.5

4.94.4-5.0

7.15.6-9.5

Cambodia 3 On-farm (427) 4.83.4-6.0

2.72.0-4.0

12.910.0-14.0

China 7 On-station w/hybrid varieties

12.49.7-15.8

10.910-11.8

13.510.5-17.5

Cuba 2 On-farm 9.158.8-9.5

6.25.8-6.6

NR

Gambia 1 On-farm (10)1 On-station

7.16.8-7.4

2.32.0-2.5

8.88.3-9.4

Indonesia 2 On-Farm5 On-station

7.46.2-8.4

5.04.1-6.7

9.07.0-10.3

Madagascar 11 On-farm(3,025)

3 On-station

7.24.2-10.35

2.61.5-3.6

13.95.6-21.0

Philippines 4 On-farm(47)

1 On-station

6.04.95-7.6

3.02.0-3.6

7.47.3-7.6

Sierra Leone 1 On-farm(160)

5.34.9-7.4

2.51.9-3.2

7.4

Sri Lanka 6 On-farm(275)

2 On-station

7.87.6-13.0

3.62.7-4.2

14.311.4-17.0

Critical Factor is Root Growth• In continuously flooded soil, 3/4 of rice roots

remain in top 6 cm (Kirk and Solivas 1997)• In continuously flooded soil, 3/4 of rice roots

degenerate by flowering (Kar et al. 1974)• In unflooded soils, “irrigated” rice varieties do

not form aerenchyma (Puard et al. 1989)• With SRI methods -- with young seedlings, wide

spacing, and soil aeration -- rice root growth is profuse

AbstractAbstractNature and growth pattern of rice root systemNature and growth pattern of rice root systemunder submerged and unsaturated conditionsunder submerged and unsaturated conditionsS. S. KarKar, S. B. , S. B. VaradeVarade, T. K. , T. K. SubramanyamSubramanyam, and B. P. , and B. P. GhildyalGhildyal,,

I l I l RisoRiso (Italy), 1974, 23:2, 173-179 (Italy), 1974, 23:2, 173-179

Plants of the rice cultivar Plants of the rice cultivar TaichungTaichung (Native) were grown in pots of (Native) were grown in pots ofsandy loam under 2 water regimes in an attempt to identify criticalsandy loam under 2 water regimes in an attempt to identify criticalroot-growth phases. Observations on root number, length, volume,root-growth phases. Observations on root number, length, volume,and dry weight were made at the early and dry weight were made at the early tilleringtillering, active , active tilleringtillering,,maximum maximum tilleringtillering, and reproductive stages., and reproductive stages.

Rice root degeneration, normally unique to submerged conditionsRice root degeneration, normally unique to submerged conditions,,increased with advance in plant growth. At stage of flowering,increased with advance in plant growth. At stage of flowering,78%78% had degeneratedhad degenerated. . During the first phase under flooding, andDuring the first phase under flooding, and

throughout the growth period throughout the growth period under unsaturated conditions,under unsaturated conditions,roots rarely degeneratedroots rarely degenerated. (emphasis added). (emphasis added)

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)

0

100

200

300

400

500

N-n n-2 Heading Maturity

Development stage

Ox

yg

en

ati

on

ab

ilit

y o

f α -

NA

(ug

/h.g

DW

)

W

S

Root cross-sections ofRoot cross-sections ofupland (left) and irrigated (right) varietiesupland (left) and irrigated (right) varieties

ORSTOM researchORSTOM research ((PuardPuard et al. 1989) et al. 1989)

With young transplants and unimpeded root growth,

• Tillering will be profuse; maximum tillering = PI -- not max. tillering < PI

• This is best understood in terms of phyllochrons -- “discovered” by the Japanese scientist Katayama (1951)

• Tillering pattern follows sequence of ‘Fibonacci series’ --1, 1, 2, 3, 5, 8, 13...

PhyllochronPhyllochron is periodic interval of is periodic interval ofgrowth common to all growth common to all gramineaegramineae

In rice, a In rice, a phyllochronphyllochron is usually ~5-8 days long is usually ~5-8 days long In each period, the plant produces In each period, the plant produces one one or moreor morephytomersphytomers from its apical from its apical meristemmeristem

Each Each phytomerphytomer is a unit of is a unit of a a tillertiller, a , a leafleaf andanda roota root -- all growing synchronously -- all growing synchronously

PhyllochronsPhyllochrons represent represent biologicalbiological rather than rather thancalendar time calendar time -- similar to degree days/leaf age-- similar to degree days/leaf age

PhyllochronsPhyllochrons are either lengthened or shortened are either lengthened or shortenedby various factors that can either by various factors that can either slow downslow down or orspeed up speed up the plant’s the plant’s “biological clock”“biological clock”

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

Better growing conditions shorten the phyllochron

• More phyllochrons of growth are then completed before the plant switches from (a) vegetative growth phase to (b) reproductive phase

• More tillering means there is also more root development

SRI capitalizes on the fact that the uptake of N is a

demand-led process

The The rate of uptake of N rate of uptake of N by rice roots by rice roots is is independent independent of theof the N concentrationN concentrationat the roots’ surface (Kirk and at the roots’ surface (Kirk and BouldinBouldin1991).1991).

[Whenever plants have sufficient N,] [Whenever plants have sufficient N,] rice roots ‘downrice roots ‘down--regulate’ their regulate’ their transport system for NHtransport system for NH4+4+ influx influx and/or ‘upand/or ‘up--regulate’ the efflux, regulate’ the efflux, thereby thereby exuding ammonium in excess exuding ammonium in excess of plant needs of plant needs ((Ladha Ladha et al. 1998).et al. 1998).

Paths for Increased Grain Yield in Relation to N Uptake, using QUEFTS

Analytical Model (Barison, 2002)

N Internal Efficiency

0

2000

4000

6000

8000

10000

12000

0 100 200 300

N uptake (kg/ha)

Gra

in y

ield

(kg/

ha)

SRI grain yield(kg/ha)

Conv. grain yield(kg/ha)

The contributions of soil microbial activity need to

be taken 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)

Consider the potentials of:

• Biological nitrogen fixation (BNF)

• P solubilization (Turner & Haygarth 2001)

• Mycorrhizal associations (VAM)

• Rhizobia (Yanni et al. 2002)

• Contributions of root exudation and rhizodeposition to soil microbial dynamics -- roots need to be understood as ‘2-way streets’ (Pinton et al. 2001)

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• SRI by raising factor productivity and

reducing need for water/agrochemicals should be beneficial particularly for poor households and for the environment

Contribution to Diversification• World doesn’t need 2x more rice output

• This would have adverse effects on price

• By raising productivity of land, labor, water and capital, we want to enable farmers to redeploy their factors of production to other crops, more nutritious and with higher economic value

• Intensification should lead to diversification and modernization of agriculture

THANK YOUMore information is available

on the SRI WEB PAGE:

http://ciifad.cornell.edu/sri/

including Sanya conference proceedings

available free in CD ROM foremat:

E-MAIL ADDRESSES:

ciifad@cornell.edu

tefysaina@simicro.mg

ntu1@cornell.edu