System of Rice Intensification

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The System of Rice Intensification (SRI) is a method of increasing the yield of rice produced in farming. It was developed in 1983 by the French Jesuit Father Henri de Laulanie in Madagascar. However full testing of the system did not occur until some years later. The productivity of SRI is under debate between supporters and critics of the system.

Contents 1 History and main ideas of SRI 2 Method 3 Rotary Weeder 4 Spread of SRI 5 Cases of Success 6 Criticism 7 References 8 External links

[edit] History and main ideas of SRI

Assembly of the practices that culminated in SRI began in the 1960s based on Fr. de Laulanie's observation of 'positive-deviant' farmer practices, starting with planting single seedlings instead of multiple seedlings in a clump, and not keeping irrigated paddy fields flooded during the rice plants' vegetative growth stage. Planting with wider spacing in a square pattern, rather than randomly or in rows, followed, as did controlling weed growth by use of a soil-aerating push-weeder (rotating hoe).^{[citation needed]}

In 1983, the beneficial effect of transplanting very young seedlings, less than 15 days old, was discovered serendipitously. Subsequently, when fertilizer prices increased, compost made from any decomposed biomass turned out to give even better results than chemical fertilizer.^{[citation needed]} SRI concepts and practices continue to evolve as they are being adapted to rain-fed (unirrigated) conditions and with transplanting being superseded by direct-seeding sometimes.

The synthesis of SRI has proceeded empirically, but the central principles for getting best results are:

• rice field soils should be kept moist rather than continuously saturated, minimizing anaerobic conditions, as this improves root growth and supports the growth and diversity of aerobic soil organisms;
• rice plants should be spaced optimally widely to permit more growth of roots and canopy and to keep all leaves photosynthetically active; and
• rice seedlings should be transplanted when young, less than 15 days old with just two leaves, quickly, shallow and carefully, to avoid trauma to roots and to minimize transplant shock.

These changes from conventional practice when managing plants, soil, water and nutrients induce more productive phenotypes from any rice genotype, although some varieties respond better than others to SRI methods. Increased yield is achieved with 80-90% reductions in seed requirements (lower plant population) and 25-50% less irrigation water. Chemical fertilizer and agrochemical crop protection can be used, but best results can be attained without use of purchased inputs.^{[citation needed]}

[edit] Method

1. Any variety suited to the locality ( except deep water rice )6 Kg /Ha
2. Treat seed with Pseudomonas flourescens for one hour and shade dry
3. Spread a polythene sheet
4. Spread 1.5 inch layer of Soil + Sand + Farm Yard Manure mixture uniformly
5. Soak paddy seed overnight in water
6. Spread seeds uniformly and cover with a thin layer of sand followed by some straw
7. Transfer the 12 day old seedlings with soil undisturbed to small trays
8. Plough twice to fine tilth
9. Puddle and level and add 10 tons/Ha of Organic manure
10. Final Levelling using wooden planks and plastering field bunds
11. Drain the field completely and after a few hours mark rows and columns using a marker or coir
12. Plant seedlings at a depth of 1.5 cms from the tray on the days it was removed from the nursery
13. Use a plant spacing of 25x25 cms
14. Maintain moisture but no standing water.
15. Weed using a conoweeder on the 10 day after transplanting
16. Remove manually all weeds not reachable by the rotary weeder
17. Repeat weeding in 10 days interval as much as possible
18. Apply fertilizers as usual
19. Control pests and diseases if threshold level is reached
20. Harvest

[edit] Rotary Weeder

Weed growth will be higher in these fields due to the absence of standing water. But since the rice plants are planted with wider spaces between rows, a rotary weeder can be drawn in between the rows of plants to remove the weeds and also aerate the soil. On the 10 day after planting weeds may not be prominent, but its better to weed so that the weeds do not get a chance to assimilate the nutrients. Modified weeders such as the conoweeder are available.^{[citation needed]} In Kerala, India the technique has been adopted by some people owing to the pressure from the Department of Agriculture and Mithraniketan ( an NGO Krishi Vignan Kendra located at Trivandrum). Failure are attributed to poor water management, non use of rotary weeder and use of older seedlings.^{[citation needed]}

[edit] Spread of SRI

The spread of SRI from Madagascar to around the globe has been credited to Norman Uphoff, director of the International Institute for Food, Agriculture and Development at Cornell University, Ithaca, New York from 1990 to 2005. In 1993, Uphoff met officials from Association Tefy Saina, the non-governmental organisation set up in Madagascar in 1990 by de Laulanie to promote SRI. After seeing the success of SRI for three years when Malagasy farmers previously averaging 2 tons/hectare averaged 8 tons/hectare with SRI, Uphoff became persuaded of the merits of the system, and in 1997 started to promote SRI in Asia. As of 2007, the beneficial effects of SRI methods had been documented in 28 countries, most recently in Bhutan, Iraq, Iran and Zambia. Governments in the largest rice-producing countries (China, India and Indonesia) are now supporting SRI extension. In India, SRI concepts and practices have been extrapolated successfully to other crops such as sugar cane, finger millet and wheat.^{[citation needed]}

[edit] Cases of Success

Several cases of success are reported in Kerala, India. The program has proven successful in Nellanad Gramapanchayat in Thiruvananthapuram. Agricultural Officers including Sreekala, Sreekumari , and Geethakumari have several cases of success.^{[citation needed]}

[edit] Criticism

There are criticisms of SRI. While supporters of SRI report many benefits in addition to yield increase -- resistance to pests and diseases, resistance to abiotic stresses like drought and storm damage, more output of polished rice (in kg) when SRI paddy (unmilled rice) is processed (bushels), less chemical pollution of soil and water resources -- critics have focused on yield suggesting that claims of increase are due to "poor record keeping and unscientific thinking". Some critics have suggested that SRI success is unique to soil conditions in Madagascar, a point that is disputed by supporters. ^[1]

Critics have objected that there is a lack of details on the methodology used in trials and a lack of publications in the peer-reviewed literature. This latter deficiency is now being remedied by such publications, but systematic trials that will satisfy scientific critics remain to be done. A global field trial is planned for 2009-2011, to be conducted by researchers from Cornell University, Wageningen University, and the International Rice Research Institute ^[2]

Additionally, the reliance on weeding/tilling machinery may limit the system's applicability.

Below is a picture gallery of SRI farming in Chattisgarh, India:

Planted field	Rice field	Nursery	Fields left almost dry
SRI field	Farmer	Crop with weeds	Weeding
Weeding	Weeding	Weeding

[edit] References

[edit] External links

• SRI at Cornell University
• Article on SRI from Nature
• News article on SRI from the BBC