Rice is the staple food of India. The country has the largest area under rice (44 million ha) accounting for almost 29% of the global rice area and is the world's second largest producer of white rice next to China, accounting for 20% of all world rice production. In order to ensure the food security of a large population in India, initiatives were taken during the First Green Revolution itself in terms of introduction of advanced technologies so as to increase crop production and productivity. Although introduction of advanced technologies has increased production, simultaneously it has increased input costs also. A saturation point has now reached and rice productivity has become almost stagnant. Further increase in inputs does not have any significant impact on productivity. Rice production in the country has also declined drastically in the past couple of years. Introduction of advanced technologies has proved beneficial to big and economically well-off farmers who could afford cost of fertilizers, pesticides and hybrid seeds. Moreover, indiscriminate use of chemical fertilizers and synthetic chemicals has drastically deteriorated soil health with adverse effect on environment and bio-diversity. At this juncture, there arises a need of a low cost and eco-friendly practice which would increase productivity in a sustainable manner. System of Rice intensification (SRI) probably is one of the answers to this impending situation. SRI methodology is a set of simple farming practices and was introduced in India a decade back. This innovation has been established as having potential to meet the requirements of poor, small and marginal farmers. Synthesis of SRI has proceeded empirically but the central underlying principles are quite simple and can easily be adopted by the poor and marginal farm holders in increasing rice production, productivity and establishing food security.
System of Rice Intensification
System of Rice Intensification (SRI) is a set of farming practices developed to increase the productivity of land, water, labour and capital by utilizing less seed, less water and less chemical fertilizer. The System of Rice Intensification (SRI) technology emphasizes on making effective utilization of resources, especially water and use of organic manures. System of rice intensification is a technology development to save water and also enhance rice yields. With SRI, there has been marked increase in root volume, profuse tillering with bigger panicles and well-filled spikelets with higher grain-weight. System of Rice Intensification was first developed in Madagascar during '80s. It originated from the close working relationships between a French priest and hundreds of Malagasy farmers, all focused on drawing out the maximum productivity from plant seeds and from their supportive growing conditions. It was not known outside Madagascar till about 1997. The last decade has witnessed its spread and adoption amongst the agriculture community in several countries across the globe. The methodology is gaining ground across Asia as more and more governments come to rely on it for food security. The validity of SRI's alternative management principles has been demonstrated in a wide range of circumstances, from high mountain regions in northern Afghanistan to the edge of the Sahara Desert in the Timbuktu region of Mali, from the marshes of southern Iraq to the tropical conditions of The Gambia and Panama. SRI is the counterpart in agricultural development of a viral idea in social media, imposing its way from the ground to the top. SRI methods are being successfully applied to other staple commodities like wheat and sugarcane in various parts of the globe, to mustard, finger-millets and vegetables in India, and teff in northeast Africa. Governments are promoting SRI in countries like China, India, Indonesia, Cambodia and Vietnam. It has progressively been on the move in East and South Africa. The spread of SRI in Cambodia has been cited as one of 15 Asian success stories in the MDGs endeavour. SRI is becoming the main rice cultivation system in most of southern China and today, SRI is seen as vital to achieving the UN Millennium Development Goals (MDGs). The potential benefits of SRI now bears testimony to its widespread adoption in predominantly rice growing countries like India, China, Philippines, Thailand, Indonesia, Bangladesh, Nepal and Sri Lanka.
An Overview of Important Agriculture Practices in Conventional and SRI
1. Seed RatePlanting of 4-6 seedlings per hill coupled with closer spacing requires more seed (30-40kg/acre) in conventional method. In contrast, planting single seedling at wider spacing drastically reduces the seed requirement to 2kg/acre in SRI. Lower seed rate facilitates maintaining seed quality and seed treatment.
2. Age of Seedling
Transplanting 30-40 days old seedling in normal method undergo 1-2 week period of plant recovery, which deprives the plant of its most prolific intervals of tiller growth.
(Kirk and Solivas, 1997). Quick, shallow and careful transplanting of seedling at 2 leaf stage in SRI avoid trauma to the roots and thereby overcome the period of plant recovery. Having nursery at a nearby place, transportation shock may be minimised.
3. Planting MethodIn SRI, square planting is done with wider spacing (25cm-30cm either side) in comparison to staggered planting with closer spacing in conventional method to permit more growth of roots and canopy and to keep all leaves photosynthetically active.
4. Water ManagementContinuous flooding in conventional method, creates anaerobic condition, constraint root functioning and ¾ th of roots degenerate by the start of the plants’ reproductive period.However in SRI the alternate wetting and drying favors more root growth, supports the growth and diversity of aerobic soil organisms and helps in better nutrient mobilization and increased microbial activity. Rewetting of dry soil reportedly facilitates nitrogen mineralization and availability for growth and yield.
In normal practices weeds are uprooted and thrown outside the field. But in SRI use of rotary weeder incorporate weeds and thereby add organic matter to the soil. Additionally, soil gets aerated and root gets all the beneficial aspects of aerobic condition.
6. Nutrient Management
Use of more synthetic chemicals in conventional method deactivates the soil micro-organism and the nutrient management is based on the principle of feeding the plant. But in SRI use of more organic matter activates the soil micro-organism/soil biota in many folds. Nutrient management in SRI is based on the principle of feeding the soil and the soil biota as a whole will feed the plant.