SRI International Network and Resources Center

FREQUENTLY ASKED QUESTIONS (FAQs)

• 1. What is SRI?
• 2. What are the main environmental, economic, and social benefits of applying the SRI methodology?
• 3. Where did SRI originate?
• 4. How has the SRI methodology spread around the world?
• 5. How does SRI benefit poor households?
• 6. How can SRI also benefit larger farmers?
• 7. Can SRI outperform "best management practices"?
• 8. Does SRI require specific plant varieties?
• 9. Does SRI have anything to do with genetically-modified organisms (GMOs)?
• 10. Is SRI an "organic" system of production?
• 11. What are the reasons for farmers to change their current rice-growing practices?

 

1. What is SRI

The System of Rice Intensification, or SRI -- le Système de Riziculture Intensive in French and la Sistema Intensivo de Cultivo Arrocero (SICA) in Spanish -- is a climate-smart and agro-ecological methodology to increase the productivity of irrigated rice (and, more recently, other crops) by changing the management of plants, soil, water and nutrients. Using the SRI methodology, yields are increased by 20-50% or more, while reducing inputs: seed by 90%, irrigation water by 30-50%, chemical fertilizer by 20-100%, and usually reduced need for pesticides. For the farmer, SRI brings greater returns to labor, land and capital.

WHAT ARE THE UNDERLYING PRINCIPLES OR SRI?

SRI methodology is based on four main, interacting principles:

• Early, quick and healthy plant establishment
• Reduced plant density
• Improved soil conditions through enrichment with organic matter
• Reduced and controlled water application
  
  

Based on these principles, farmers adapt SRI practices to their climate zone, and to their agro-ecological and socio-economic conditions. Most common adaptations respond to soil conditions, water control, changing weather patterns, access to organic inputs, the decision to practice fully organic agriculture or not, access to labor, mechanization, and other socio-economic factors.

In addition to irrigated rice, the SRI principles have been applied to rainfed rice and to other crops, such as wheat, sugarcane, teff, finger millet, mustard, and pulses all of which show increased productivity over current conventional planting practices. When SRI principles are applied to other crops, we refer to it as the System of Crop Intensification or SCI (see SCI section of the website for details.)

WHAT ARE THE KEY SRI PRACTICES FOR IRRIGATED RICE?

The key SRI practices for irrigated rice production are summarized below.

Cultivation Practices	Standard Methods	SRI Methods
Seed Selection	Seeds not treated	Seeds are soaked for 24 hours prior to seedign to eliminate non-viable seeds
Nursery management	Flooded nurseries, densely seeded	Non-flooded nurseries, often raised beds non-densley seeded
Age of seedling when planted	21-30 days, sometimes up to 60 days	8-12 days, representing the 2-leaf stage
Spacing	Hills are 10-15 cm apart, in rows or random spacing	Hills in square pattern, with spacing > 25x25cm or more
Number of plants/hill	305 plants/hill; 130-500 plants per m2	1 plant/hill (<16 plants per m2)
Water management	Continuous flooding of fields during crop cycle	Alternate wetting and drying
Weed control	Hand weeding, or herbicide use	Mechanical weeding, aerating the soil
Fertilization	reliance on chemical fertilizers	Organic matter as base fertilization, complemented if needed with chemical fertilizer

RECOMMENDED SRI MANAGEMENT PRACTICES FOR IRRIGATED CONDITIONS

Seed treatment and nursery management:
Seeds are soaked in a large container of water for 24 hours. Viable seeds sink to the bottom and non-viable seeds float to the surface, and can easily be removed. Seeds are sown non-densely in a seedbed with good soil structure. Each plant has space to grow, and roots can develop easily and will not get entangled with each other.

Transplanting young seedlings at the 2 leaf-stage. Seedlings are grown in a non-flooded nursery and removed carefully with minimal trauma to the roots. Seedlings should be replanted quickly and carefully, at a shallow depth of only 1-2 cm deep, assuring that the roots are not dried out or damaged. Some adaptations for direct-seeding and mechanical transplanting have been developed in a number of countries.

Reducing plant density through i) planting one seedling per hill, and ii) increased spacing between the plants, usually at 25cm x 25 cm, planted in a square pattern. In less fertile soils and with low tillering rice varieties, spacing can be reduced to 20cm x 20cm, with profusely tillering rice varieties and organic matter enriched soils, spacing can be increased to 30cm x 30cm, or possibly to 35cm x 35cm (rarely more).

Reducing irrigation water application:
Only a shallow water layer of 1-2 cm is introduced into the paddy field during the vegetative period. The plot is left to dry until cracks become visible, when another thin layer of water is introduced. This is called ‘intermittent irrigation’ or ‘Alternative Wetting and Drying’ (AWD). During flowering, a thin layer of water is maintained, followed by AWD during the grain filling period, before draining the paddy 2-3 weeks before harvest. Some farmers irrigate every evening, others leave the fields to dry over a 3-8 day period, depending on soil and climate conditions, and control over irrigation water. The drying period creates aerobic conditions allowing roots to better develop.

Enhancing soil organic matter
The soils are enriched with organic matter to improve soil structure, nutrient and water holding capacity, and to favor soil microbial development. Adding organic matter represents the base fertilization, which is complemented if needed by fertilizer, most often urea. Most common organic matter sources are compost, animal manure, green manure, and crop residues such as rice straw.

Controlling weeds is done through mechanical weeding, mostly done with a simple push-weeder. Weeds grow more vigorously under non- flooded field conditions, and need to be kept under control from an early stage.
Frequent use of the mechanical weeder is ideal, up to 4 times starting at 10 days after transplanting and repeated every 7-10 days until the canopy is closing. Mechanical weeding has multiple functions and benefits:

• Incorporation of weeds into the soil, where their nutrients are recycled,
• Superficial tillage improves soil aeration
• Root growth is stimulated through some root pruning and soil aeration
• As water, organic matter and soils are mixed anew and oxygenized through the weeding process, nutrients become better available to the plants. A re-greening effect of the plants can be observed 1-2 days after weeding.
• A redistribution of water across the plot through the weeding process, contributes to a continuous leveling of the plot and eliminates water patches in lower laying areas in the field that create anaerobic conditions for the plants.
  
  

The use of the weeder creates homogeneous field conditions, a more uniform crop stand and leads to increased yields.

Overview Publication: More Rice for People, More Water for the Planet
This publication details experiences from Oxfam America, World Wildlife Fund (WWF), and Africare, including what farmers and policymakers say about SRI, the relevance of SRI to climate change, and reports from Mali, Vietnam and India showing SRI impacts in very different climatic and cultural contexts.

2. What are the main environmental, economic, and social benefits of applying the SRI methodology?

Benefits include increased yields of 20-50% or more, a 90% reduction in seed use, and up to 50% water savings. SRI methods have shown these significant benefits across all ecological zones in over 50 countries, and have been adopted largely by smallholder farmers in Asia, Africa and Latin America and the Caribbean.

By reducing inputs of seed, water, chemical fertilizers, and in some cases labor, SRI gives greater returns to farmers' available resources of land, labor and capital and can lower their production costs. This increases farmers’ incomes and increases the profitability of rice farming.

Use of pesticide can be decreased because SRI plants are stronger and healthier. Disease pressure is reduced when plants are widely spaced because humidity levels in the plant canopy are lower than in more densely planted conventional fields.

Use of chemical fertilizer can be reduced significantly as fertilizer use efficiency increases in soils enriched with organic matter. As soils become healthier and more fertile through period organic matter amendments, less fertilizer is needed to achieve a targeted production level. If the soil is sufficiently fertile, use of chemical fertilizer can be eliminated.

Because plants are stronger and more deeply rooted, SRI crop stands show greater resilience towards drought, strong winds and storms. These hazards are becoming more frequent and more extreme with climate change.

SRI management usually shortens the crop cycle by 1-2 weeks. This frees up land for other uses, and reduces crop exposure to biotic and abiotic stresses and risks.

SRI paddy rice produces a 10% -- or more -- higher outturn of polished rice when milled, which means a higher return for the farmer. In addition, SRI grain quality is better, exhibiting fuller grains and reduced chalkiness.

Additional environmental benefits include:

• Increased water availability at the landscape level or for other consumption needs, as irrigation water use can be reduced by up to 50% under SRI,
  
• Improved soil and water quality, through the reduction of agrochemicals use
• Increase in soil carbon pools through the additions of organic matter to soils
• Reduction in methane emissions from rice paddies through non-flooded rice paddy conditions
• Biodiversity of rice cultivars can be maintained and enhanced, as local varieties become more productive and thus more attractive for farmers to grow

3. Where did SRI originate?

SRI was developed in Madagascar by a French priest, Father Henri de Laulanié, S.J., who spent 34 years (1961-1995) working with farmers there to improve rural livelihoods through increased rice productivity. The main practices of SRI were synthesized by the mid-1980s. With Malagasy colleagues, Laulanié established a local non-profit, Association Tefy Saina, in 1990. Tefy Saina promoted the knowledge of SRI methodology and its use as part of a holistic rural development strategy.

4. How has the SRI methodology spread around the world?

Tefy Saina and the Cornell International Institute for Food, Agriculture and Development (CIIFAD) began working together in 1994 on a USAID-funded project to conserve the rainforest ecosystem of Ranomafana. Following three years of on-farm comparisons, which showed consistent increases in farmers' yields from 2 tons/ha to 8 tons/hectare, CIIFAD began to bring the SRI methodology to international attention after 1997.

Outside Madagascar, higher rice productivity using SRI methods was first validated in China and Indonesia during 1999-2000. The following year, similar results were reported from Cambodia, Philippines, Cuba, Sri Lanka, India, Myanmar, the Gambia, and Sierra Leone. By 2002, SRI methods had been validated in 15 countries; by early 2013, this number had grown to 51, including most of South and Southeast Asia, and also certain countries in West Africa.

A leading SRI website, maintained at Cornell University by the SRI International Network and Resources Center (SRI-Rice), has supported widespread distribution of SRI information -- experiences, problems, solutions, innovations, etc. -- including massive email communication among members of the international network. Jim Carrey’s Better U Foundation supports the work of SRI-Rice to catalyze worldwide spread of SRI ideas and practice. Within many countries, SRI users and proponents have formed their own networks, including list-serves, websites, or blogs. Information is freely available, with no restrictions.

The knowledge and practice of SRI has spread through the efforts of a growing network of interested persons and institutions: NGOs, universities or research institutions, government agencies, the private sector; and most of all by farmers themselves. CIIFAD has played an important role in networking and knowledge-sharing throughout the years.

5. How does SRI benefit poor households?

Poor households usually have very limited access to land and capital, so raising yield per unit area with reduced outside inputs is of great importance. The first objective for poor farmers is usually to feed their own families. Higher yields of 20-50% or more have a significant impact on farm families’ food security. When food security is assured, households can diversify their economic activities, either on-farm or off-farm.

As SRI is a knowledge-based intensification method, poor farmers are less dependent on outside inputs and can improve their agricultural crop production with locally available resources. Once the SRI methodology is adopted by a large segment of the farmers, it can be expected that with more local rice available and reaching markets in greater abundance, urban poor benefit from lower rice prices and good quality local rice, and are less exposed to fluctuating prices of imported rice.

It should be noted that SRI has spread most quickly among poor households, which in turn has led governments, research organizations and development agencies to pay attention to this novel approach to agricultural intensification.

6. How can SRI also benefit larger farmers?

Because SRI capitalizes on biological processes, on the genetic potential of the crop, and on the plant-soil-microbial interactions, the benefits are scale-neutral. The SRI principles for intensifying agriculture are available to any producer, who can adapt the cropping practices to suit local conditions. Efforts to mechanize transplanting, direct seeding, and weeding are underway in a number of countries for small to large-scale agriculture. We expect that SRI principles will soon be utilized at different scales.

7. Can SRI outperform "best management practices"?

It has been argued that SRI may improve upon farmers' original practices, but not upon the best management practices proposed by rice scientists. To counter this assertion, we note that the new world record for rice production was obtained in 2011 by a SRI farmer in Bihar state in India, who obtained a paddy yield of 20.2 t/ha (dry yield) or 22.4 t/ha (wet yield).

But yield is not the only factor that matters in crop production. Best management practices often depend heavily upon outside resources such as improved seeds in large quantities for densely planted fields, and large amounts of water and agro-chemicals. SRI practices optimize the use of local resources, and significantly reduce the amount of seeds, water and agro-chemicals needed, while at the same time increasing yields.

8. Does SRI require specific plant varieties?

SRI methodology is a management approach, and does not require new varieties. Improved plant performance can be observed with any variety when planted with SRI methods. This is because the plants can better express their genetic potential when they are grown in a more optimal environment. High-yielding varieties or traditional ones, 'improved' or 'unimproved,' hybrids or landraces, all perform better when planted with SRI methods, although some varieties respond better than others.

Farmers show greater interest in growing local varieties when using the SRI methodology, as their higher yield level makes them more profitable. Farmers often prefer local varieties for taste, for their better adaptation to local soil and climate conditions, and better and pest and disease resistance. SRI allows farmers to maintain and increase the diversity of planted rice varieties.

9. Does SRI have anything to do with genetically-modified organisms (GMOs)?

SRI gains are achieved through better crop management, and do not depend on any particular genetic traits of rice plants, although invariably some varieties perform better than others under SRI management.

SRI is an alternative to -- or competitive with -- GMOs only in that its yield improvements and other benefits are greater than what is usually expected from making genetic modifications. With the SRI methodology rice productivity can be increased immediately (by 20-50% or more) using existing genotypes and local resources at a very low cost. It requires no further research, no intellectual property rights are attached, and it is available for everyone. This makes the high investments into the development and use of GMOs less urgent for meeting world food needs.

10. Is SRI an "organic" system of production?

Enriching and improving soils with organic matter is one of the four basic principles of SRI. As soils are improved through organic matter additions, many nutrients become available to the plant from the organic matter. Additionally, the soils are able to hold more nutrients in the rooting zone and release them when the plants need them. Depending on the yield level and on the farming system, some farmers use exclusive organic fertilization for their SRI plots. The majority of farmers complement the organic matter amendment with chemical fertilizers, most often urea, in order to achieve a balanced fertilization of the crop.

It is interesting to note that in times when chemical fertilizers cannot reach rural communities due to political instabilities, destructive climate events or infrastructure problems, or are unaffordable for poor farmers, SRI farmers have the knowledge to continue producing high rice yields, whereas under conventional farming methods, dependence on external inputs makes farmers more vulnerable to outside events.

11. What are the reasons for farmers to change their current rice-growing practices?

Smallholder farmers in Africa, Asia and Latin America can find it difficult to improve their production following conventional intensification recommendations. The (New) Green Revolution paradigm requires improved seeds, fertilizers and other chemical inputs, which are often unaffordable or unavailable to farmers. Additionally, many farmers who do use chemical fertilizers experience stagnation and decrease in crop productivity over time, as the soils’ fertility is slowly degrading. This is a result of substituting the strategy to restore or improve soil fertility with the exclusive use of fertilizers.

When introduced to SRI, many smallholders in Africa, Asia and Latin America are ready to test the practices and adapt them to their conditions. In most cases, it is the farmers who lead the uptake of these new crop management ideas, followed only later by technicians and researchers.