The SYSTEM of RICE INTENSIFICATION- SRI
known as le Systéme de Riziculture Intensive in French and la Sistema Intensivo de
Cultivo Arrocero (SICA) in Spanish -- is a methodology for increasing the productivity of irrigated rice cultivation by changing the management of plants, soil, water and nutrients. SRI practices lead to healthier, more productive soil and plants by supporting greater root growth and by nurturing the abundance and diversity of soil organisms.
The agroecological principles that contribute to SRI effectiveness have good scientific bases. SRI concepts and methods have been successfully adapted to upland unirrigated rice, and they are now being extrapolated to other crops like millet, wheat and sugar cane SRI does not require the purchase of new seeds or the use of new high-yielding varieties.
Although the highest yields with SRI have been obtained from improved varieties, most traditional or local varieties of rice respond well to SRI practices and command a higher market price. And while chemical fertilizer and agrochemicals can be applied with SRI, their use is not required as organic materials (compost, manure or any decomposed vegetation) can give good or even better results at low cost. Farmers report that when SRI methods are used correctly, rice plants are better able to resist damage from pests and diseases, reducing or eliminating need for agrochemical protection.
Because plant populations are greatly reduced with SRI, seed costs are cut by 80-90%, and because paddy fields are not kept continuously flooded, there are water savings of 25 to 50%, a major benefit in many places. However, cessation of flooding means that increased weeding is required. If this is done with soil-aerating implements like a rotating hoe, this cost has a benefit of enhanced crop production.
SRI does require skillful management of the factors of production and, at least initially, more labor, particularly for careful transplanting and for weeding. Since yield increases are usually 50 to 100%, and possibly several times present levels, the returns to labor can be very great. The profitability of rice production can be greatly increased when yield goes up with a reduction in the costs of production. As farmers gain skill and confidence in SRI methods, their labor input in fact decreases, and over time SRI can even become labor saving compared with conventional rice-growing methods.
SRI is a work in progress, with improvements continually being made, including better implements and techniques that further reduce labor requirements. Farmers are encouraged to make their own improvements in SRI methods and to share experience within the farming community.
Yield is the most evident (and controversial) feature of SRI, but many other considerations are also driving its spread around the world. Additional information on SRI benefits such as resistance to drought and storm damage, shorter time to maturity, and more milled rice resulting when SRI paddy is processed can be found in a paper on: Features of the System of Rice Intensification apart from Increases in Yield.