System of Rice Intensification : An innovative method for sustainable rice production

A. Satyanarayana=

Nuziveedu Seeds Limited, 7c, Surya To= wers, Secunderabad-3

Rice fee= ds more than half the world’s population and 400 million are suffering f= rom chronic hunger in rice-producing areas of Asia, Africa and South America. According to the United Nations, demand for rice is expected to rise by a further 38% within 30 years but yields of rice are plateauing or even declining in recent years. So, the= re should be newer ways of stepping up of Rice production. SRI is one definite= way of doing it.

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The irrigated rice is the leading consumer of water. Scarcity of water for agricultural production is becoming a major problem in all he world&= #8217;s leading rice producing countries. Finding ways to reduce the demand for water to grow irrigated rice is essential. If rice production can<= /span> be increased while water consumption is reduced, is so much the better. SRI fields are not flooded. They are only ke= pt moist and as a result 40-60% irrigation water is saved.

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The Syst= em of Rice Intensification, An innovative method of cultivation of rice, which change the way that rice plants, soil, water = and nutrients are managed. This s= ystem has the potential to double the rice productivity with = less inputs namely seed (90%), chemical fertilizers, pesticides and water (40-60%) only through changes in the management practices. These methods of rice cultivation viz., planting young seedlings (8-12 days) at wider spacing (25x25 cm)= carefully on the soil that is kept aerated with abundant and diverse microorganisms increased yields and at the same time cost of production is lowered.&n= bsp; The System of Rice Intensification was introduced in Andhra Pradesh during Kharif 2003 in all the 22 districts in the form of 250 on-farm trials each on= 0.4 ha area. The far= mers were educated about the methodologies through various extension activities.= SRI was an instant success with an average productivity of 8.36 t/ha compared to 4.9 t/ha with the conventional method The highest productivity recorded during Kharif 2003= was 16.2 t/ha followed by 15.7 t/ha while during Rabi 17.25 t/ha was achieved u= nder farmer field conditions. All rice varieties respond positively to SRI. The phenotype of the rice varietie= s look differentl= y under SRI with robust tillers, big panicles supported by large root system. The luxuriant root gr= owth of SRI plant is probably stimulated by the production of phyto harmones by aerobic microb= ia in the soil which are multiplied abundantly with SRI practices. Thus, the principle behind SRI pot= ential is the large and functional root system. The soils that are aerated and well supplied with organic matter supported larger and diverse populations of microorganisms which in turn mobilizes nutrients to the plant; phytohormones produced by bacteria and fungi living in soils and roots promotes growth and health of plants.; root exudates provide food for microorganisms; application of fertilizers and other agrochemicals= has inhibiting effect on soil biota. &nbs= p; SRI is the best example of eco-agriculture which utilizes biological power.

SRI was developed nearly 20 years ago by Father Henri de Laulanie, a Jesuit priest who w= orked with farming communities in Madagascar from 1961 until his death in 1995. The System of Rice Intensification was discovered almost by accident in 1983-84. Due to a lack of time for letting rice seedlings grow for 30 days before being transplanted, students in a fa= rm school at Antsirabe (1,500 meters <= span class=3DSpellE>a.s.l.) in Madagascar were asked to use very small nursery twice in a month. Then some seedlings = were transplanted after only 15 days. Given the very high number of tillers obta= ined per plant with this accidental experiment, still younger seedlings were tri= ed – at only 12 days, 10 days, even 8 days after seedlings emerged in the nursery. It was found that this led to a substantial increase in the number= of tillers per plant (60 to 80 or more). That was the beginning of the System = of Rice Intensification. Other methodologies are aimed at cost saving such as single seedling planted wider spacing, use of organics to reduce dependence= on chemicals or external inputs etc.

De Laulanie synthesized a set of simple but synergistic practices that now constitute SRI (Laulanie, 19= 93). Norman Uphoff, Director of the Cornell Internat= ional Institute for Food, Agriculture and Development at Co= rnell University, USA, began promoting SRI throughout Asia sinc= e 1997 when he continuously observed over 8 t/ha rice yields with SRI both in experimental plots and farmers fields with less external inputs compared to 2 t/ha with conventional methods.

The potential ben= efits of SRI are being tested now in more than 25 countries from Bangladesh to Thailand. SRI is being promot= ed in all the 22 districts in Andhra Pradesh since 2003. About 1,00,000 farmers are practicing this system in India now.<= /h1>

Essential principles of the system:

a) Transplanting young seedlings of 08- 12 days old, singly in a square pattern.

b) Careful transplanting av= oids shock or trauma while transplanting

c) Wider spacing 25 x 25 cm or even more. <= o:p>

d) Weeding and Aeration:

&= nbsp; Use simple mechanical rotary weeder to churn the so= il for weed control. Rotate the weeder at least 2 to 4 times. This incorporates the weeds into t= he soil. Weeds incorporate into = the soil also help build&n= bsp; up of large and diverse microbial population in the soil. Since transplantation is done in a square pattern rotary hoeing can be done in two directions, and promotes greater soil aeration, which is beneficial for aerobic microbes, like mycorrhizal fungi. Mycorrhizal fungi absorb not just N, P and K, but also Ca, S, Fe, = Mn, Cu and Zn from the soil and translocate them to= the plants in whose roots they have established themselves. The soil Microorgan= isms and Biota are creators and maintainers of soil fertility. The micro-organis= ms present in the soil mobilizes nutrients and plant growth promotors to the plants.

e) Water management:= Water is not allowed to st= agnate under SRI method. Regular irrigations are given to keep the soil moist. Alternate ‘wetting and drying’ combined with mechanical weeding, results in more air in the soil and greater root growth. =

f) Organic manures:<= span style=3D'font-size:11.0pt;font-family:Garamond'> Instead of chemical fertil= izers, FYM, Green manures or compost is applied liberally. As a result, more plant growth is achieved due to better soil health and more balanced nutrient sup= ply. Apply diverse organic manures, which act as food for microorganisms to dive= rse micro organisms. “ It is the synergist= ic effect of all these components of SRI that is crucial ” One has to ai= m to achieve them.

Benefits of S= RI

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a) Water saving upto 40 – 60 %. Productivity of water is greatly enhanced with SRI

b) Saving on seed: Only 5 kg of seeds per hectare compared to 50 kg in traditional rice cultivation.

c) Edge effect: Planting is done at wider spacing = at 25 x 25cm or more. This gives border effect to all the plants in the field leading to robust growth larger root = and high tillering with big panicles.

d) Pest & Disease Con= trol: Because SRI plants have a more favorable growing environment, they are more vigorous. The more vigorous a plant is, the more it can resist pests and diseases, sheath blight is reduced by 70 % and BPH incidence is low under S= RI method.

e) Resistance to abiotic stresses: Given the larger, healthier root sy= stems of SRI plants, they have been observed to resist damage from cyclone, cold, hurricane, drought and Zinc deficiency

f) Matures early : Under SRI, the rice = crop is maturing 10 days earlier than with usual cultivation practices, irrespec= tive of the variety.

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SRI utilizes Biological Power

- &nb= sp; = Rice root system grown und= er SRI (i.e. aerated soil) do not degenerate, and are much larger and funct= ion better.

- &nb= sp; = Soils that are aerated and well supplied with organic matter can support larger and diverse populations of microorganisms which in turn mobilizes nutrients to the plant.<= o:p>

- &nb= sp; = Phytohormones produced by bacteria and fungi living in soils and roots promotes growth and health of plants.

- &nb= sp; = Root exudates provide food for microorganisms<= o:p>

- &nb= sp; = Application of fertilizers and other agrochemi= cals has inhibiting effect on soil biota.

- &nb= sp; = The performance of SRI in A.P., Since 2003 is disc= ussed.

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