By changing the management of plants, water, soil, and nutrients, SRI puts readily available resources to more productive use, thereby increasing the quantity and quality of yields, reducing greenhouse gas emissions, and benefiting all involved.
A proven sustainable, 'paradigm shifting' methodology
SRI promotes robust and healthier plants through a variety of practices. These practices can be adopted singularly, but their combination produces the best outcomes for a plants' health and in terms of yield.
With larger root systems, due to reduced plant density, SRI increases the quality of nutrients absorbed by the rice plant.
Rice paddies are a major source of methane. SRI encourages aerobic soil conditions through alternate wetting and drying and mechanical weeding, which can directly and significantly impact methane emissions.
AWD can significantly mitigate methane emissions. There is also evidence to suggest SRI reduces nitrous oxide emissions, whilst increasing carbon sequestration through larger root systems.
SRI produces a lot from very little. Supportive institutional environments from national governments and international organisations can play a vital role in furthering SRI benefits.
SRI offers a variety of benefits for women. SRI improves their health, lifestyle, status, and consequently improves the lives of their families who they work to support.
SRI promotes robust and healthier plants through a variety of practices. These practices can be adopted singularly, but their combination produces the best outcomes for plants' health and therefore also in terms of yield.
When SRI methods are implemented in their entirety, yields are increased usually by 20-50%, and often by 100-200%, compared to traditional rice cultivation methods.
SRI farmers are careful to select only the best seeds to plant.
Seed selection is carried out in an easy and cost-effective way by soaking the seeds in a water and salt solution for 24 hours and removing the floating seeds.
By adopting this simple process the rate of seed germination is enhanced.
Seedlings are transplanted when they are 8-12 days old.
SRI farmers transplant seedlings at a very young age, under 15 days, when the seedlings are at the 2-leaf stage. During transplantation, farmers must be careful to protect the seedlings’ roots and minimise transplanting shock. This allows seedlings to grow faster and stronger by preserving the inherent growth potential of the plant.
Seedlings are planted in a grid format, usually 25 cm by 25cm.
SRI farmers plant one or two seedlings per hill instead of a handful together, so that root competition is avoided, following a grid pattern of 25x25cm. On average, SRI reduces seed requirement by 90%. More space between plants encourages greater root and canopy growth, which results in higher rates of photosynthesis and lower transpiration (the evaporation of water from plants). Lower transpiration results in more tillers and panicles which contain more and heavier grains.
Fields are managed using alternate wetting and drying (AWD).
Using AWD allows for aerobic soil conditions. This prevents the roots from degenerating which occurs during continuous flooding of paddy fields as per conventional rice cultivation methods.
Simple mechanical equipment is used to control weeds.
Avoiding flooded conditions can encourage weed growth which needs to be kept under control. SRI farmers are encouraged to adopt simple mechanical weeders and start the operations 10 days after transplanting, repeating every 7-10 days until the canopy is closed. By incorporating the weeds into the soil, farmers enrich their fields and aerate the soil, making nutrients newly available to the plant.
See below for a variety of factors that contribute to SRI successfully mitigating greenhouse gas emissions, particularly methane.
By using non-flooded conditions through AWD and encouraging aerobic conditions, the methane emissions produced are dramatically reduced.
SRI plants have expanded root systems, allowing them to sequestrate more CO2 into the soil.
By avoiding agrochemicals, the emissions associated with producing, manufacturing, and transporting those products are also avoided.
Enhancing yields per unit area reduces the need for expansion of farming area, therefore preventing the disruption of ecosystems and the resulting GHG emissions.
There is evidence from an ongoing SRI project in Northern Nigeria that nitrous oxide emissions are also reduced through SRI. This has been demonstrated during the project's pilot stage during the wet season.
Following SRI methods can significantly reduce methane emissions caused during traditional rice cultivation.
"Cutting methane is the single fastest, most effective opportunity to reduce climate change risks in the near term because, unlike carbon dioxide, methane's warming power doesn't come from a gradual buildup over time but is almost entirely from recent emissions"
Rice paddies are a major source of methane (CH4) due to methane-fermenting anaerobic bacteria, known as methanogens. Methanogens can only survive in soil that is kept in a steady continuous anaerobic condition (where there is no oxygen), which is the standard condition of conventionally flooded rice paddies. Methanogens thrive in this environment, resulting in irrigated rice cultivation being one of the major sources of methane emissions, accounting for up to 12% of human caused methane emissions.
SRI offers a significant and effective method to tackle methane emissions by working with nature. SRI encourages aerobic soil conditions through the use of Alternate Wetting and Drying (AWD). AWD allows the soil to make contact with oxygen molecules, which immediately kills the methanogens. Aerobic soil conditions are further enhanced by using a mechanical weeder, allowing oxygen to penetrate the soil by moving upper thin layer of topsoil. SRI has also been shown to increase aerobic bacteria, known as methanotrophs, that consume methane.
SRI provides an actionable and immediate way to significantly reduce methane emissions. By applying AWD water management, a core practice of SRI, methane emissions can be reduced by up to 70%.
SRI improves the nutritional quality of rice by promoting healthy soil and root systems, resulting in healthier plants and more micronutrients.
The micronutrients then transfer to the grain leading to approximately 40% more nutrients and denser grains compared to conventional practices. Tests have shown that SRI grains are usually more dense, meaning less breakage during milling.
SRI also reduces uptake of harmful substances like arsenic by up to 10-15 times.
It does this by promoting organic fertilizers and chemical-free pest control methods.
When combined this lowers health risks like cancer, neurological and skin disorders. This is especially important for those who rely on rice as a staple food, greatly improving their quality of life.
More women are involved in rice cultivation than in any other livelihood activity; an estimated 500 million women worldwide.
Women play a leading contribution to rice cultivation, although this is often poorly acknowledged. With increasing numbers of men migrating to urban areas in search of work, the role and importance of women in rice farming cannot be understated.
SRI is gaining popularity around the world in large part due to its appeal to women.
SRI offers a variety of benefits for women.
Women typically handle transplanting, weeding, and family care, making their workload challenging. SRI demands more effort initially to learn, but once grasped, reduces labour requirements by 90% and enables upright mechanical weeders. Thus, women benefit from decreased traditional rice cultivation burdens and enhanced daily lives.
SRI helps women increase their income by reducing initial costs and providing space for other crops. This also improves their own and their family's health and lifestyles. SRI also enables women to pursue other employment opportunities and improve their standard of living.
Increased and more reliable yields allow women to achieve greater food security for their families. Furthermore, as SRI can supply a family's necessary rice quantity from a reduced area, other household land can instead be used to grow a variety of fruits, vegetables, or rear livestock; improving nutrition and incomes.
Empowering women in SRI can accelerate its uptake. Women have been shown to attend classes more regularly and provide enhanced knowledge dissemination in comparison with men. In doing so, women have been able to increase their own social statuses within their communities, gaining respect and further exerting influence in promoting sustainable policies and practices.
Traditional rice cultivation involves working in unsanitary conditions, bent-over for hours in flooded, muddy fields. SRI reduces health risks associated with such work by using AWD, mechanical weeders, and reducing agrochemical use.
This helps prevent illnesses like skin irritations, gynaecological problems, and water-borne diseases. SRI also eliminates mosquito habitats by eliminating flooded fields. If an entire community implements SRI this can break the reproductive cycle of mosquitos that carry diseases like malaria and dengue, and thereby stop them from affecting farmers.
SRI produces a lot from very little.
Further support and investments should focus on the dissemination of knowledge and resources through effective and quality extension work. Supportive institutional environments from both national governments and international organisations play a vital role in guiding this. SRI would also greatly benefit from the technical support mentioned below.
Further research into mechanisation technology would increase upscaling of SRI, both for small and large-scale farmers. Strengthening and structuring distribution channels for equipment would also enhance and accelerate SRI adoption.
With water scarcity increasing, careful management of water systems is vital for supporting food systems and the environment. The reliability of water access is a key factor for the successful implementation of SRI. Improving irrigation infrastructures, through participatory irrigation management schemes for example, allows farmers to have greater access and control over the irrigation of their crops.
SRI encourages the use of organic matter for soil enrichment. A reliable and quality source of organic matter that can be used as green fertiliser is beneficial for the full application of SRI. Investments for research into the development of optimal organic fertilisers produced from biomasses available to smallholder farmers can improve both yield performance and SRI's positive effects on soil health.
SRI results in more nutritious rice and improved environments. These positive features translate into economic incentives to adopt SRI practices which would be achieved through certifications and specialised channels for distribution. Specialised channels for acquiring, processing, and selling SRI rice will provide consumers with higher quality foods, whilst also ensuring greater remuneration for producers and traders.
Direct climate finance and development funding from various sources should support and integrate SRI into agricultural projects. Carbon credits can also aid SRI farmers as SRI plays a crucial role in mitigating global warming by reducing GHG emissions and sequestering more carbon in the soil. Incentivizing SRI climate-smart methods by rewarding farmers for their efforts can encourage more farmers to adopt them.