The System of Rice Intensification (SRI):

PracticesCornell International Institute for Food, Agriculture

and Development (CIIFAD)

and Association Tefy Saina, Madagascar

I. SRI Around the World:Africa, Latin America, Asia

An SRI field at Ambatovy, Madagascar, 2003

Cuba -- CPA Camilo Cienfuegos cooperative -- 14 t/ha

An SRI field in Sri Lanka, 2002 – 13 t/ha yield

SRI field in Yunnan, China, hybrid variety, 2004 – 18 t/ha

I. BASIC IDEAS FOR SRI

SRI is a set of principles and methods that help farmers get more productive rice plants from ANY VARIETY of rice

SRI methods accomplish this improvement by making changes in the management of plants, soil, water, and nutrients to

(a) induce greater ROOT GROWTH, and (b) nurture more abundant and diverse

populations of SOIL ORGANISMS

SRI Practices Should Always be Varied to Suit Conditions

The basic practices -- starting points -- are:• Transplant young seedlings ( < 15 days ) –

although direct-seeding is becoming an option

• Wide spacing – single plants, in square pattern

• Soil aeration – thru water management and weeding, so aerobic conditions prevail in soil

• Organic matter added to enhance the soil – fertilizer is not needed but it does raise SRI yield

Weed control with ‘rotating hoe’ is recommended Farmer innovation is an important part of SRI

LESS CAN PRODUCE MOREby utilizing biological potentials & processes• Smaller, younger seedlings become

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

higher yield if used with other SRI practices• Half as much water produces more rice

because aerobic soil conditions are better• Fewer or even no purchased inputs can

make greater output possible, because soil organisms increase and are more active

• Living soil is the key to SRI performance

III. SRI PRACTICES

Seed Preparation

• Seed selection

• Seed amounts

• Nursery size as ratio to field

• Seed preparation (soaking, warming)

• Etc.

If Transplanting -- Start with Young Seedlings

• SRI can be practiced with direct seeding

• Many farmers are experimenting with this, and have good results -- saving labor

• But many farmers prefer transplanting because it assures good establishment

• The critical thing is to PROTECT AND TAKE GOOD CARE OF THE ROOTS

• These are the key to SRI success

SRI Nurseries are Like a Garden

• No continuous flooding of the seedlings

• Soil should be light and easy to work with – so seedlings can be separated when transplanting

• Mixture of organic matter with the soil

Conventional nursery in Tamil Nadu, India

SRI nursery

in Tamil Nadu, India

Small nursery in Sri LankaNote that this is enough

for much larger fieldNote also elevation of soil to keep roots from being

suffocated by water

Note rake-marker on left, used to mark square pattern on field

Transplanting is Most Important Operation for SRI

• Young seedlings, 8-12 days old (< 15 d), should be removed carefully from the nursery, keeping the seed sack attached to the roots

• Transplanting should be done within 15-30 minutes after removal from nursery, keeping mud attached to root so that it does not dry out

10-day-old seedlings being taken

from nursery, very carefully

Pulling out of seedlings in Tamil Nadu

Conventional SRI

Transport of seedlings

Conventional SRI

Planting in a Square Pattern with Wide Spacing is Important• Square spacing will permit efficient

weeding with rotary hoe

• Recommend to start with 25x25 cm spacing; but 30x30 or 35x35 better?

• If soil is very good, or as it improves with SRI practice, spacing can be greater, eventually to 40x40 or even 50x50 cm

Different Methods for Spacing

• SRI was developed using strings across the field tied to sticks; this gives good precision but takes time

• Most popular method now is use of a simple wooden rake with desired spacing, pulled in two directions

• Most recent innovation is a roller-marker that is cheap and saves time

Conventional planting

SRI planting in Tamil Nadu

Field marking with rake

Separating seedlingsfor transplanting

Yellow color is from sunlight

Planting seedlings shallow,only 1-2 cm deep,

keeping seedling roots as horizontal as possible

Roller-marker devised by Lakshmana Reddy, East Godavari,AP, India, to mark a square pattern on field and save timein transplanting operations; his yield in 2003-04 season

was 16.2 t/ha paddy rice (dry weight)

Transplanted fields in Tamil Nadu, India

Conventional

SRI

Careful Transplanting Is Key• Plants should be set into muddy soil

no deeper than 1-2 cm

• Seedlings should not be pushed down into the soil– This will turn the root tip upward and slow

the plant’s resumption of growth– The seedling shape should be more like

an L than like a J

• Direct seeding is being experimented with by some farmers to save labor

Seeder developed by Luis Romero, Cuba, for planting

pregerminated seed, sowing 40x40 cm (too wide)

Variations in Plant Establishment• Broadcast germinated seed or young

seedlings – seeding rate of 25 kg/ha – developed by A. Subasinghe, Sri Lanka

• After about 10 days, use rotating-hoe weeder to ‘weed’ the field as normal recommended for SRI

• This THINS the crop, leaving only a few plants (1-2) at each intersection of rows

• This method saves labor for making a nursery and for transplanting seedlings

Variations in Plant Establishment• In China, a ‘triangular’ method for trans-

planting was developed by Liu Zhibin, farm manager in Meishan, Sichuan

• This increases plant population by having 3 plants per hill with – wider spacing between hills and – fewer hills

• The best spacing for particular soil and climate conditions and particular variety should be determined by experimentation

• Spacing between plants is 7-10 cm

40cm

40cm

Square planting with single seedling

Original

SRI

Improved

SRI

45cm

40cm

7cm

Oblong planting with triangle pattern

Transplanting Pattern

Yield(T/ha)

Comparison with CK

+ T/ha + %

Traditional (CK) 8.65 -- --

Standard SRI 10.42 1.77 20.4Oblong + triangle

SRI 13.39 4.74 54.8

Comparison between Triangle SRI andStandard SRI (SAAS, 2002)

Innovation Is Part of SRI• Kadiramangalam method developed by

Gopal Swaminathan, Tamil Nadu, India: – where intense summer heat is too much for

tiny young seedlings, he transplants them in hills of 3 at 15 days at 30x30 cm spacing, and re-transplants at 30 days at 30x30 cm

– this method takes more labor, but it gives 100% survival rate and assured yield of 8 t/ha

• Farmers are encouraged to experiment with variations in timing, spacing, etc. to find best practices for their conditions

Innovation Is Part of SRI• Gopal Swaminathan, Tamil Nadu, India,

has also developed a 4-row weeder that works with his soils and saves time

• Ariyaratna Subasinghe, Sri Lanka, has built a motorized weeder that greatly reduces his labor time for weeding, so he can handle 2 ha SRI rice field by himself

• Farmers are encouraged and expected to make further improvements in SRI methods as they gain experience with it

4-row weeder designedby Gopal Swaminathan,

Tamil Nadu, India

Motorizedweeder

developed byS. Ariyaratna,

Sri Lanka

Weeding Is Important for Yield• This activity does more than remove weeds

• Mechanical weeding with rotating hoe or cono-weeder– Returns weeds (organic matter) to the soil– Aerates the soil, supporting soil organisms

• We have some evidence that additional weedings will add to yield, without fertilizer

• Farmers can experiment for themselves weeding different parts of field 2x, 3x or 4x

Effects of Weeding on YieldResults for 76 farmers around

Ambatovaky, Madagascar, 1997-98

No. of No. of Average Ave.

weedings farmers yield (t/ha) increase

None* 2 5.9 --

One/two 35 7.5 1.6

Three 24 9.1 1.6

Four 15 11.7 2.6

*Hand-weeding only; labor cost for weeding was about $25/ha

Conventional weeding

Rotary weeder

Handle

Using rotary weeder

Cono-weeder

Using cono weeder

Good Water Management Is Required for Best Results

• During weeding, fields are flooded -- but otherwise, fields are not kept flooded

• The ideal is to provide the plant with a ‘minimum of water,’ i.e., enough water to meet plants’ needs, but not so much that:– Roots’ access to oxygen is interrupted,

since they air to keep from degenerating, or – Soil organisms which need oxygen are lost

and only anaerobic organisms survive

Water Management Methods Can Vary• Original recommendation was to add

small amounts of water on daily basis, preferably in afternoon or evening, enough to wet the soil, and to drain off any remaining excess the next morning

• This would be done during the period of vegetative growth, with several periods of no watering for 3-6 days, to dry soil

• After panicle initiation, only 1-2 cm of water is kept on the field until 10 days before harvest -- when field is drained

Water Management Methods Can Vary• This may be more water than needed

• Many farmers practice alternate wetting and drying (AWD), flooding field for 3-6 days, then draining it to be dry 3-6 days

• This reduces labor requirements; yield may be lower, but labor cost is less

• Best amounts and timing of water will depend on soil and other factors

• Farmers are encouraged to experiment to determine best water practices for field

Conventional irrigation

Water-saving irrigation

Case Study from China: Evaluation of SRI in Xinsheng Village, Dongxi Township, Jianyang County, Sichuan Province, August 2004, done for China Agricultural University (Li et al., 2004)

• 2003 – 7 farmers used SRI • 2004 – 398 farmers used SRI (65%)• 2003 – SRI plot size average 0.07 mu• 2004 – SRI plot size average 0.99 mu• 86.6% of SRI farmers (65/75) said they

would expand their SRI area next year or keep their whole rice area under SRI

• Why the rapid acceptance of SRI?

2003 WAS A DROUGHT YEAR

RICE YIELD (t/ha) 2002 2003 2004Standard 6.02 4.47 5.64

MethodsSRI Methods -- 6.60 7.61(SRI Increase) (46.6%) (34.8%)

Water saving/ha was calculated at 43.2%• However, farmers in both questionnaire

survey and discussion groups said that labor-saving was SRI’s greatest benefit

IV. Advantages of SRI beyond Yield Increases

• Cost reduction and increased profitability – can reduce water, seed, labor and other inputs

• Lower capital requirements – more accessible for poorer households, help with food security

• Resistence to pests and diseases – farmers can reduce or end their use of agrochemical sprays

• Resistance to climatic effects – greater tolerance to drought, cold, storm and salinity, no lodging

• Environmental benefits – less chemical use, lower water demand, fewer greenhouse gases?

• Lower risk – less chance of net losses from rice production

• Higher grain quality – higher milling out-turn, better eating qualities, more nutritious rice?

• Biodiversity conservation – traditional varieties

Other Benefits from SRI Methods

Two rice fields in Sri Lanka -- same variety,same irrigation system, and same drought :

conventional methods (left), SRI (right)

MEASURED DIFFERENCES IN GRAIN QUALITY Characteristic SRI (3 spacings) Conventional Diff.

Chalky kernels (%)

23.62 - 32.47 39.89 - 41.07 - 30.7

General chalkiness (%)

1.02 - 4.04 6.74 - 7.17 - 65.7

Milled rice outturn (%)

53.58 - 54.41 41.54 - 51.46 + 16.1

Head milled rice (%)

41.81 - 50.84 38.87 - 39.99 + 17.5

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

SRI STILL RAISES MORE QUESTIONS THAN WE HAVE

ANSWERS FOR• There are many researchable issues to

be taken up by scientists, in association with farmers and with extension personnel

• However, enough is known now to pursue a two-pronged strategy with (a) research and (b) practice proceeding in parallel

THANK YOU

Email: ciifad@cornell.eduor tefysaina.tnr@simicro.mg

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

Effects of SRI vs. Conventional PracticesComparing Varietal and Soil Differences

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