SRI is Different From Traditional Rice Growing Methods

To appreciate the novelty of SRI requires some understanding of how rice is grown. As anyone knows who has traveled in Asia and wondered at the miles of luminescent green paddies, irrigated rice is normally grown covered by water. Although rice is a very adaptable plant, it is not an aquatic plant and by the end of a growing cycle the roots of rice plants kept in flooded conditions have started to die from lack of oxygen. Flooding is primarily to suppress weeds.

Unflooded Rice Fields

Farmers following SRI principles do not flood their fields. Instead they alternate the wetting and drying of rice paddies. And instead of randomly transplanting clumps of rice seedlings, 4 weeks old or more, into flooded fields, they plant very young seedlings (8-15 days) singly and carefully in rows with wide spacing. Soil is then kept moist but not flooded.

This exposes the soil and the beneficial organisms living in it to the air and sun. Adding compost to the soil builds the health of the soil. Controlling weeds with a simple rotary weeder actively aerates the soil, delivering oxygen to the roots and soil organisms. Larger, healthier root systems and more abundant and diverse communities of soil organisms enable the plants to produce many more grain-bearing tillers (stalks), bigger panicles (ears of grain), heavier grains, and more biomass, which is a benefit to poor households who need the straw for animal fodder.

Higher Yields, Less Inputs

With SRI methods, average yields are 6 to 7 tons of rice per hectare (a hectare is about 2.5 acres), compared to usual yields of 2 to 4 tons/hectare with farmer practices. This matches or exceeds the yields of input-intensive cultivation using high-yielding varieties (HYVs), fertilizer and pesticides, all of which entail considerable economic and environmental cost. Yields as high as 10 tons per hectare or more are often achieved with SRI.

Each of the management practices used in SRI makes a positive difference in the yield, but the real potential of SRI is seen when the practices are used together. SRI is a work in progress. Farmers are encouraged to make their own improvements in SRI methods and to share experiences within the farming community. SRI concepts and methods have been successfully adapted to upland unirrigated rice, and they are now being applied to other crops like millet, wheat and sugar cane.

Resources

• World Bank Toolkit SRI - Achieving More with Less: A New Way of Rice Cultivation
• Cornell International Institute for Food, Agriculture and Development (CIIFAD) SRI Website
• Watershed Support Services and Activities Network (WASSAN) SRI Website