The System of Rice Intensification (SRI)

An Opportunity for the Rice Sector and Rice-Wheat Farming Systems?

Norman UphoffCIIFAD Forum, Cornell University

More tillers and more than 400 grains per panicle

Potential Benefits from SRI:

• Increased yields – average ~ 8 t/ha, yields up to 12-15 t/ha, without changing variety

• Higher factor productivity – for land, labor, capital and water

• Reduced water requirements – up to 50%• Environmentally benign -- reduced or no

use of agrochemicals• Accessible to the poor because low-cost

Limitations with SRI

• Requirement of good water control – need ability to apply small amounts on as-needed basis

• Increased labor requirements to begin with; higher returns to labor, eventually can become labor-saving per hectare

• More appropriate for small-scale production – not adverse for a poverty reduction effort

• Credibility – sounds “too good to be true”

Growing Evidence for SRI

• 3 years ago, SRI practiced only in Madagascar• Since 1999, trials, mostly successful, have been

undertaken in Bangladesh, Cambodia, China, Cuba, Gambia, India, Indonesia, Laos, Myanmar, Nepal, Philippines, Sierra Leone, Sri Lanka, and Thailand; others starting: Brazil, Peru, Pakistan, etc.

• Part of Indonesia’s new national strategy for rice improvement after three years of AARD trials

Data from Reports to 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

SRI Practices Produce Superior Phenotype from Existing Genes

• Much larger root system -- ~ 5 times more resistance to uprooting; accessing more soil

• Correspondingly more tillering – 30-50 tillers per plant, up to 80-100 or more

• Greater grain filling, as a result – positive correlation between tillers/plant and grains/ panicle, contrary to what literature reports

SRI Practices

• Transplant young seedlings – 8-12 days• Transplant very carefully – little trauma• Wide spacing of plants – 1 per hill and

square pattern: 25x25cm, or even wider• No continuously flooded paddies during

vegetative growth phase; then limited water• Soil-aerating weeding with ‘rotary hoe’• Compost application is recommended

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These practices together:

• Keep roots alive; they begin dying from second week with continuous flooding

• Encourage deep rooting; withstand drought; acquire more and more complete nutrients

• Support profuse tillering and canopy growth• Help plants to resist pests and diseases• Nurture abundance and diversity of soil

microbial populations, benefit plant growth

Figure 1. Plant type and light intensity of SRI at heading stage Tao Longxing, Wang Xi and Min Shaokai, China National Rice Research Institute (2002)

Root growth with SRI

Figure 2. Dry matter distribution of roots in SRI and CK (conventional) plants at heading stage (root dry weight in g)

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SRI Raises More Questions than We Currently Have Answers For• SRI has been practice-led – developed

empirically in Madagascar in early 1980s• Scientific explanations are accumulating

or being formulated –• e.g., biological nitrogen fixation (BNF),

P solubilization, possible contribution of mycorrhizae, role of increased exudation into rhizosphere …

Practical Implications are Many

• Could reverse current stagnation in rice yield improvement

• Could reduce water requirements for rice, thus alleviating ecological pressures and political conflicts

• Different water management practices could benefit wheat production in rice-wheat systems

• Food security could be more attainable by poorer households not needing heavy capital investments

Researchers Can Draw on Work in other Countries

• Can benefit from knowledge base being developed elsewhere

• SRI practices always need to be adapted to local conditions for best results – not a “technology” to be adopted

• SRI proceeds with farmer participation in experimentation and evaluation, thereby raising human capital

Three-Cornered Partnership

• Researchers• Extension personnel• Farmers

• Two parallel tracks:• Scientific investigation and evaluation• Farmer-to-farmer communication