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1829 - Understanding the System of Rice Intensification (SRI) for Sustainable Rice Production

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Author: Dr. T. M. Thiyagarajan, Dean Faculty of Agricultural Sciences, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India
Title: Understanding the System of Rice Intensification (SRI) for Sustainable Rice Production
Presented at: The International Conference on Climate Change, Biodiversity and Sustainable Agriculture
Venue: Assam Agricultural University, Jorhat, Assam, India
Date: December 13-16

Published in: Environment
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1829 - Understanding the System of Rice Intensification (SRI) for Sustainable Rice Production

  1. 1. Understanding the System of Rice Intensification (SRI) for Sustainable Rice Production Dr. T. M. Thiyagarajan Dean, Faculty of Agricultural Sciences SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu Former Director, Centre for Soil And Crop Management Studies Former Dean, Agricultural College & Research Institute, Killkulam Tamil Nadu Agricultural University
  2. 2. Rice is a very well ‘evolved’ crop • it can be raised by - throwing or planting dry seeds or sprouted seeds; - transplanting or throwing of young or older seedlings; - planting randomly or in lines at any spacing; - flooded or alternate wet and dry moisture regimes - apply different sources and amounts of nutrients. • So, it grows under very wide range of environments
  3. 3. Yield Potential • The yield of a crop cultivar when grown in environments to which it is adapted, with nutrients and water not limiting growth, and with pests and diseases effectively controlled. • Growing conditions are usually less perfect than that is required for achieving full genetic potential. • Genetic potential is the amount of production that a plant is genetically capable of producing, if all the conditions required for growth and performance are optimal.
  4. 4. THE BEST and IDEAL growing environment for rice to express its genetic potential • We probably may never know this, as includes the growing aerial environment (radiation, temperature, rain, humidity, pests) and the soil environment (water, nutrients, temperature, chemistry, biology, drainage, microbiology, inputs) which can vary in innumerable permutations and combinations, more than are humanly possible to create and investigate in the field. • Determining a better environment provided by good management practices will help us to reach towards genetic potential
  5. 5. Approaches to maximize yield potential • breeding High yielding varieties • speeding up the multiplication of crop genomes using a technique called genome doubling. • transference of C4 plant mechanisms into C3 plants
  6. 6. –In the conventional sense : formal, top-down recommendations for improved varieties, increased plant densities, and increased use of external inputs (mineral fertilisers, pesticides), or –In an agro-ecological sense: a grass-roots movement, knowledge-intensive, soil-health oriented, building soil biodiversity, savings on labour and external inputs (seeds and chemicals); capitalising on farmer know-how to cope with the location-specificity of farming Sustainable Rice Production
  7. 7. System of Rice Intensification An agro-ecological and knowledge-based methodology for increasing the productivity of irrigated rice by changing the management of plants, soil, water and nutrients while reducing dependency on external inputs * Farmers have developed effective SRI adaptations for rainfed rice production
  8. 8. What is SRI ? Growing rice with: Early establishment of seedlings; Fewer, widely-spaced transplanted population (although direct-seeded SRI is possible); Regular intercultivation; Root-friendly irrigation; and Supplementation with organic manures
  9. 9. System of Rice Intensification • Provides a different and better growing environment, to which any cultivar responds positively (although some respond better than others; local varieties perform well). • More productive phenotypes are produced which are characterized by higher number of tillers per plant, increased plant height, longer and wider leaves, longer panicles, more grains per panicle, and improved grain quality.
  10. 10. Basic Principles of SRI • Early and careful crop establishment • Lower transplant density & population • Root care: unflooded irrigation • Soil health care: intercultivation • Soil biodiversity care : organic manures
  11. 11. System of Rice Intensification • attempts to substantially increase rice yields merely by changing the way the rice crop is established and managed in the field. • is based on certain theoretical arguments about the growth patterns and physiology of rice plants. • aims to exploit the vigorous growth exhibited by rice plants when sown thinly in the seedling nursery and transplanted when still very young, at a low density, into the main field. • involves the principle that sparse irrigation and soil disturbance – intended to foster aerobic soil conditions – will stimulate highly productive interactions between rice roots and beneficial soil micro- organisms
  12. 12. How different are the SRI practices from conventional practices?
  13. 13. Younger Seedlings Conventional SRI Age 3 – 5 weeks 8 – 15 days Nursery area (sq.m to plant 1 ha) 810 100 Seed rate ( kg to plant 1 ha) 20 - 60 7.5 Growth stage Tillering 2-3 leaves Population density Crowded Sparse Transplanting shock exists Nil Tillering potential reduced high • Young seedlings concept was known earlier with ‘dapog’ method of nursery
  14. 14. Single Seedlings per hill and wider spacing Conventional SRI No.of seedlings per hill 2 -6 1 Pattern of planting Random / line square Spacing (cm) 20 x 10, 15 x 10 random 25 x 25 No. of plants at transplanting (per sq.m) 100 – 200+ 16 Tools used Ropes rarely Ropes, markers • Single seedlings are used in hybrid rice seed production • ‘Gaja’ method of planting (single seedling and wider spacing) was developed by a Tamil Nadu farmer in 1907 • Single seedling planting was being popularized during 1910s and 1920s in Madras presidency
  15. 15. Intercultivation • Is not generally a recommended practice in rice cultivation • But a Tamil Nadu farmer practiced intercultivation in 1907 • Intercultivation experiments were conducted in Japan during 1949-52. • Intercultivation was favoured by a few scientists • Soil strirring is an important principle in SRI • In SRI, intercultivation is recommended to be followed until the canopy closes, at 10-day intervals, whether there are weeds or not -- the principle is to intercultivate the soil for active soil aeration, not just to remove weeds; weeds become ‘green manure.’
  16. 16. Intercultivation
  17. 17. Theories on the effect of Intercultivation • A kind of physico-chemical change occurs in the soil which causes decomposition of organic matter in the soil and thus increases the supply of nutrients • decreases the amount of toxic gases in the soil and increases the amount of useful oxygen accessible there at the same time • Cutting of roots promotes the growth rate of plants • The cumulative effect of all these processes is that the final yield is increased to a great extent. Nojima (1960)
  18. 18. SRI irrigation regime • Considers not just the plant water requirement, but also the air requirement of the roots and soil biota. • Provide the growing plants with sufficient but never excess water, so that the roots do not suffocate and degenerate. • Soil should be mostly aerobic most of time, and not continuously saturated so as to benefit the growth and functioning of both plant roots and aerobic soil biota.
  19. 19. SRI Crop Cycle
  20. 20. How SRI Creates a Different and Favourable Growing Environment?
  21. 21. The changes brought about in the growing environment of the plants due to the use of young single seedlings, wider spacing, soil- aerating weeder operations, and reduced, controlled irrigation have been found to have a positive influence on the growth of plants as well as on the soil dynamics in a manner not found in non-SRI cultivation
  22. 22. Effects of SRI practices on the above-ground environment • Soil is exposed to sunlight and atmospheric air frequently • Availability of more sunlight for the leaves and enhanced photosynthesis in the canopy • Photosynthesis is also enabled in lower leaves • Intercultivation results in some earthing-up effect • Leaves remain green even after reaching maturity • Leaves had higher light utilization capacity and greater photosynthetic rate, especially during the reproductive and ripening stages of the crop. • Less incidence of pests and diseases • Reduction or absence of rodent damage in SRI fields
  23. 23. Effects of SRI practices on the below-ground environment • Rice plants under SRI can have 10 times more root mass, about 5 times more root length density, and about 7 times more root volume in the top 30 cm of soil profile, compared with the roots in plots of flooded rice • The is less or negligible root degeneration from suffocation • Mixing aerobic and anaerobic soil horizons by intercultivation triggers growth • Significant differences in soil microbial populations; higher levels of enzyme activity in SRI plant rhizospheres are indicative of increased N and P availability; also more soil microbial C and N
  24. 24. Effect of SRI on crop growth
  25. 25. Phenotypical alterations in SRI crop • More open plant architecture with more erect and larger leaves • Profuse tillering and more panicles • Longer panicles, more grains per panicle, higher percentage of grain-filling • Higher leaf chlorophyll content at ripening stage • Delayed senescence or leaves • Greater fluorescence efficiency • Higher photosynthesis rate • Lower rates of transpiration (higher water efficiency) • More efficient in the uptake and utilization of nitrogen
  26. 26. ‘More SRI crop per drop’ • Reductions in irrigation water requirements by 30-50% per hectare • Higher water productivity – more output of grain per unit of water input – by 30-100%
  27. 27. Improved productivity 29% Less water requirement 32% Reduced cost of cultivation 10-12% Lower GHG emission -1.3 t CO2 eq ha-1 More income $ 340 ha-1 Benefits of SRI Details Conv SRI % Yield (Kg / Ha) 5,400 7,150 32% Grain revenue @ $ 15.50 /100 Kg 840 1,112 32% Straw revenue @ $ 0.50 /100 Kg 50 65 30% Total revenue ( $ / Ha) 890 1177 32% Total expendi-ture ( $ / Ha) 476 424 -11% Net profit ($ / Ha) 414 754 82% Cost-benefit ratio 1.87 2.78 49% Conventional SRI $ 476 $ 424 11% reduction in expenditure/ha Effects of SRI
  28. 28. Expansion of carbon sinks • SRI rice plants sequester more carbon, with higher grain and straw yield, and with more root biomass • Increased soil organic matter through SRI practices that improve the soil with more organic matter application and with increased root exudation into the rhizosphere; this nurtures larger soil biota • Associated agro-ecological practices sequester carbon, such as green manure production, integration with agroforestry, surface mulch applications, etc. • Reduced carbon footprint due to less use of agrochemicals (including effects of less manufacturing and shipping of fertilizer)
  29. 29. SRI and climate change mitigation Flooded rice paddies are a major source of methane (CH4), a greenhouse gas (GHG) that is roughly 30 times more potent than carbon dioxide (CO2), the main GHG contributing to global warming and to climate change. Rice paddies contribute about 15-20% of the total methane emissions that human activities currently generate and propel into the atmosphere Creating aerobic soil conditions in rice paddies can increase the potential for production and emission of nitrous oxide (N2O). This is a GHG about 300 times more potent than CO2 Intermittent paddy irrigation by SRI or AWD reduces methane emissions by between 22% and 64% Nitrous oxide increases are not very great and do not offset or cancel out the benefits from SRI and AWD reductions in methane emissions. Net GHG reductions with intermittent irrigation have ranged between 20% and 40%, and even up to 73% A comprehensive analysis of GHG emissions associated with SRI methods in India, including CO2, calculated these to be reduced by 40% Concerns Findings
  30. 30. GHG IMPACT ASSESSMENT: IAMWARM (per year)  Estimated annual climate change mitigation benefit due to IAMWARM: 449,984 tons Co2 eq  Alternate wetting & drying with SRI reduced GHG emissions by 391,000 tons Co2 eq Components Without Project With Project Balance Rice/SRI 14,299.90 6,483.88 - 7,816.03 Livestock 5,906.79 5,841.37 - 65.42 Annual Crops 349.21 -1193.92 - 1,543.14 Units: 000’s tons Co2 eq
  31. 31. Resistance to drought, floods, storms, pests, diseases • Improved drought resistance of SRI plants which thrive with 30-50% less irrigation water per land area, due to deeper, larger, less-senescing root systems • Reduced competition among plants creates stronger plants above and below ground • Organic matter-enriched soils are able to store more water and to furnish nutrients better
  32. 32. Practices / Variations / Alternatives in Adopting SRI Principles
  33. 33. Early Crop Establishment Ideal Practice Where the principle may not work or be adopted? What is the alternative?  Seedlings should not have more than 2-3 leaves  8-14 day-old seedlings under usual conditions  Saline soils  Saline irrigation water  Difficulties in acquiring / using young seedlings  Cold ambient temperatures  Use older seedlings, preferably under 3 weeks old  Plant 2 or 3 seedlings per hill  Follow all other SRI principles of wider spacing, intercultivation and limited irrigation
  34. 34. Lower Transplant Density & Population Ideal Practice Where the principle may not work or be adopted? What is the alternative?  Single seedling per hill  Wider spacing: 20 x 20 cm is the minimal requirement to enable weeder use; 25x25 cm is more commonly appropriate; or 30x30 cm if soil is very fertile  Square planting to enable weeder to be used in both directions (perpendicularly)  In low organic matter soils or where high rate of organic manures cannot be applied, greater width should not be adopted  Where there is less skill or non-cooperation of planting labourers  20 x 20 cm is sufficient in poor, low fertility soils  If the first SRI crop does not allow 3rd intercultivation due to crowded tillers, spacing should be increased in the next season  If square planting is not possible, at least have wider spacing of rows  If single seedlings are not possible, plant not more than 2 per hill  Follow all other SRI principles
  35. 35. Root-friendly Irrigation Ideal Practice Where the principle may not work or be adopted? What is the alternative?  Unflooded irrigation to a thin layer, allowing the water to drain/dry up, getting the soil exposed to sunlight until it develops thin cracks. This practice is followed until flowering.  After flowering, irrigating with a thin layer of water and not allowing the soil to develop cracks. The plants should not experience water scarcity  A thin water layer should be available at time of inter-cultivation  Impossible to get the soil exposed to enough sunlight  Field always remains flooded due to seepage which saturates soil  Cascade irrigation under tank ayacuts  Ignore SRI irrigation principle if no possibility of good water control.  Plant 3-week-old seedlings  If establishment is in doubt, plant 2 seedlings per hill  Follow other SRI principles
  36. 36. Improving soil quality - Intercultivation Ideal Practice Where the principle may not work or be adopted? What is the alternative?  Using a weeder at 10-day intervals after transplanting, up to 4 times or until the canopy closes, whichever is earlier  Use the weeder in both directions to get maximum soil aeration  Weeds that remain after weeder use should be removed by hand  Intercultivation should be done even if there are no weeds, because this controls weeds pre-emptively, and also aerates the soil to promote growth of roots and soil microbes  Skilled labour is not available  Labour is unwilling to do this work  Weeder is not available  Available weeder is not suitable for the kind of soil  Pay more wages so labourers get compensated with more income while farmer has increased profit  Do weeding at least twice, on 15th and 30th day after transplanting  Do weeding in one direction and after 10 days in the other direction  Where there is no square planting, do weeding 4 times in one direction and hand-remove weeds within the rows  Follow other SRI principles
  37. 37. Improving soil quality – Organic manures Ideal Practice Where the principle may not work or be adopted? What is the alternative?  Apply green leaf manures, cattle manure, compost, crop residues to the extent possible  Apply biofertilizers where available  Non- availability of sources of organic matter  Grow Gliricidia on the bunds to have a permanent source of green leaf manure  Use available quantities of organic manure and supplement with chemical fertilizers  Fertilizers can be used, but the tradeoff is less nurturing of the life in the soil
  38. 38. SRI in West Africa
  39. 39. SRI in Latin America
  40. 40. SRI in Philippines
  41. 41. SRI in Lower Mekong Delta
  42. 42. Global spread of SRI (2017)
  43. 43. Sustainable Sugarcane Initiative (SSI) EID Parry Company has developed a unique 3-tier nursery programme using the tissue culture technology. This is integrated with Sustainable Sugarcane Initiative (SSI) production. Producing sugarcane seedlings has turned profitable for a farmer, near Avalpoondurai, in Erode The SSI method of sugarcane cultivation was evolved from the principles of ‘More with Less’ followed in SRI (System of Rice Intensification) and introduced in India by the WWF-ICRISAT collaborative project in 2009. SSI methods can increase sugarcane yields by at least 20% with 30% less water and a 25% reduction in chemical inputs.
  44. 44. System of Millet Intensification - Odisha System of Millet Intensification has increased production of small and marginal farmers in PRAGATIi, Koraput action areas of Nandapur block
  45. 45. System of Wheat Intensification (SWI) Practiced in Bihar, Madhya Pradesh, Rajasthan, Chhattisgarh, and Uttarakhand, Nepal, Pakistan, Ethiopia, and Mali Superior performance of the direct-seeded version of SWI on plant height, root length and volume, grain, straw, and total biological yield, economic returns, and residual soil fertility. SWI methods also performed well under adverse weather conditions in 2012–2013, being able to sustain wheat production under climatic stress, demonstrating risk-mitigation and climate- resilience potential
  46. 46. Conclusions • SRI is a ready opportunity for climate-smart rice production • Requires no major investments in infrastructure, research or input subsidies • Farm families can consume more rice and improve their incomes within one or two cropping seasons • Farmers in over 60 countries have seen these effects of SRI management are applying these new principles.
  47. 47. SRI Knowledge Centre (http://sri.cals.cornell.edu)

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