PERADENIYA: SRI (System of Rice Intensification) has yielded almost double paddy harvest with fewer investments, as compared to conventional practice of paddy cultivation in Sri Lanka since the year 2000.
The average production through SRI in the country is 7.6 metric tones per hectare where as the current national average yield is 3.97 metric tones per hectare. SRI produced the highest yield of 15.8 metric tones per hectare from the improved variety of BG 403(a four month variety), and 9.6 metric tones per hectare from Ratbbel, a traditional variety.
SRI requires less water, less seed, more soil organic matter and more soil aeration to achieve the highest productive potential. It is a low-cost, low-input, eco-friendly technique avoiding the use of chemical fertilizer, and pesticide. It reduces health hazards to the farmers.
It is emerging as an alternative to conventional water and chemical intensive rice cultivation. It was originated in Madagascar during 1980s, remained confined there till 1999. Now it is being practised all around the world from a small scale to a larger scale of 40 -50 hectares.
SRI practices involve transplanting only one seedling of 8 to 15 days old per hill at a distance of 25X25 centimetres to 40X40 centimetres based on the nutrient availability of the soil. Plants uptake their required moisture and nutrients, and withstand wind and drought through a maximum of 9 inches deep and well spread root system.
Only minimum water is applied during the vegetative growth period, and then a thin layer of water is maintained. For the nutrients, compost made from any biomass is used. Since not being flooded, weed becomes a problem.
Two to four weeding is practised from 10 to 12 days after transplanting to before canopy closes. Labour saving weeder is used. Motorized weeder, invented by a Sri Lankan farmer, requires 2.5 to 5 days for weeding a hectare of paddy field.
Studies conducted by Sri Lankan farmers found that- SRI requires only 10 kilogram of seed per hectare, and 25 to 50 percent less water than conventional practices. It requires Rs. 3 per kilogram of paddy production, where as that is Rs. 6 per kilogram with conventional practices.