SRI FEATURE ARTICLE: EARTH DAY! April 22, 2016
EARTH DAY: Farmers Using the System of Rice Intensification are Doing Their Part
Combining Climate Change Mitigation with Adaptation Activities for Farmers at the Field Level
Earth Day comes every April to remind us of what we could and should do... And it's a good time to think about how the System of Rice Intensification (SRI) can help! Using less water, less agrochemicals, and less seed to get higher yields can help reduce the growing assault on the earth's resources and environment. SRI has a role to play in mitigating climate change by 1) reducing standing water (see photo at left), leading to decreased methane emissions; 2) reducing inorganic fertilizer use (and the nitrous oxide that urea generates) as well as decreasing carbon and nitrogen emissions from the manufacturing of fertilizers and their subsequent transportation over long distances; and 3) sustainably increasing the productivity of existing land, preventing the conversion of carbon sequestering forests to agricultural uses. (See methods section if you are uncertain what SRI methods entail).
However, while SRI does help to protect the environment, using SRI methods also helps farmers to adapt to climate change: Stronger roots help rice plants resist lodging in inclement weather, better withstand drought conditions, and, as indicated in recent reports from Sri Lanka, even help withstand flooding! (See photo at right of Harouna's large-rooted SRI rice plant in Timbuktu, Mali).
In Asia, where 40% of all fresh water is estimated to be diverted for rice irrigation, a single kilogram of rice requires an average of 2,500 liters of water (but can be as high as 5,000)! Since much less water is required with SRI, more farmers can share the available water; this is especially important as increasingly unpredictable weather patterns cause water shortages. In fact, state governments in Tamil Nadu, Bihar, and elsewhere in India are currently promoting SRI, partly due to the water savings.
Of course, the benefits of SRI are not all related to climate change. The number of countries reporting increased yields, another advantage of SRI, is approaching sixty, and, health-related effects are being studied as well. In Kenya, research results from Jomo Kenyatta University of Agriculture and Technology indicate that SRI water management can help break the mosquito breeding cycle and shows good prospects for malaria control. Another health impact is related to the probable reduction of arsenic levels in rice grown with SRI. While research will be completed this summer, we expect to find lower arsenic levels in SRI-grown rice. This is not surprising though, since reducing water is rice paddies generally reduces arsenic in the rice plant, and SRI methods recommend substantial reduction in water use.
Is It Magic?
It sounds like magic, but it's really just about working with plants and the environment in a climate-smart way that encourages nature to work for us! In short, SRI is based on reducing plant populations and water usage while improving soil conditions. SRI methods focus on providing optimal environmental conditions for individual plants rather than concentrating on managing dense plant populations. Planting single seedlings (instead of the usual 3+) with wider spacing (25cm x 25cm or more) reduces competition for nutrients; allows the canopy to open more fully to intercept more light for photosynthesis; and produces a less humid microclimate within the plant stand which is less favorable to pests and diseases. Planting younger seedlings (12 days old or less, instead of the usual 20+ days) encourages recovery from transplanting shock and leads to better root development. Using less water and improving soil with organic matter additionally promotes stronger, healthier roots, which in turn leads to increased tillering (when spacing is increased), more resistance to abiotic stresses and certain insects, a higher percentage of filled grains, and ultimately, a higher yield.
Is There a Downside?
No, it's not a silver bullet, and SRI may not be a perfect fit for everyone's farm! In fact, even when it is a good fit, is not always easy to convince farmers to use SRI. There is a learning curve involved, and, farmers frequently are somewhat resistant to changing longstanding traditions that have served them well in the past. Variations in established labor patterns can be problematic, the necessity for water control can be an issue, and there are more weeds to contend with. (Manual and motorized weeders, which also aerate the soil and stimulate root growth, have greatly reduced labor requirement associated with weeding though.)
Finally, despite a reduction in methane emission, a question not yet completely clarified is whether nitrous oxide is decreased or increased with some of the SRI adaptations. So far, we have only studies that show a decrease of nitrous oxide, but there are more studies to be done! (Both methane, which is generated under flooded conditions, and nitrous oxide are important greenhouse gasses).
So, although SRI methods have been shown to increase yields in an environmentally sustainable way and to both mitigate climate change and help farmers to adapt to it, there are still some questions about where, how and why the System of Rice Intensification actually works. You can follow the story as it unfolds on our SRI website. We will keep you posted with the latest updates!
Is SRI for you?
You may want to look into it! You can try the "full SRI" or fit it to your own needs. (The System of Rice Intensification is "open source," so it is intended to be adapted to your own environmental, socioeconomic and cultural context.) Have a look at our videos page, instructional manuals page, methods page and FAQs, or, if you want to try your own research, head to the SRI-Rice research articles page!
Finally, you can adapt SRI principles, not only for rice in rainfed areas, but also to other crops, but this is a story for another day...
- HAPPY EARTH DAY !
- - Lucy Fisher and the SRI-Rice Team