The System of Rice Intensification, known as SRI, is an innovation in rice production systems by raising productivity of the land, labor, water and capital. SRI is a set of modified practices for managing rice plants and the soil, water and nutrients. SRI can produce more paddy yield with less external inputs. Furthermore, SRI is environment-friendly. SRI method can be adopted to any type of rice variety (local variety, HYV, hybrid variety). SRI is an innovation that is constituted entirely of knowledge, but not depending on external inputs and materials.
History of SRI:-
SRI was developed in 1980’s by Fr. Henri de Laulanié, S.J., who spent half a lifetime in Madagascar, working with poor farmers to improve their rice productivity and output so as to alleviate poverty. SRI was discovered by Prof. Dr. Norman Thomas Uphoff, CIIFAD, Cornell University, USA, in 1993 when he visited Madagascar to lead a study mission. He arranged a field test of SRI for 5 years in Madagascar to confirm the SRI effects. After his conviction on SRI, with an utmost dedication, he has disseminated SRI worldwide from 1997 to date.
SRI methodology is based on four main principles that interact with each other:
Early, quick and healthy plant establishment.
Reduced plant density.
Improved soil conditions through enrichment with organic matter.
Reduced and controlled water application.
Reported benefits of SRI:-
Increase in yield/ha –52% (21 to 105%).
Increased net income/ha –128%(59 –412% ).
Reduction in cost of production –24%(7 –56%)
Reduction in water. requirement –44%(24 –60%)
Shorter time to maturity (1-3 weeks less).
Protection against biotic stresses pests/diseases (Sheath blight, leaf folder, brown plant hopper) –70% reduction in incidence.
Tolerant to abiotic stresses -drought, storm damage, extreme temperatures.
Higher milling outturn (by ~ 15%) –lower chalkiness.
Uphoff (2007); Zhao et al. (2009); Thakur et al. (2010)
SRI is a concept consisting of the following practices (menu).
Transplant young seedlings.
Transplant single seedling at a hill with utmost care for seed roots.
Transplant at wider spacing.
Less use of chemicals (fertilizer, pesticide, insecticide, herbicide).
Less water use by applying wet-dry cycle of soil moisture.
The SRI concept is nowadays applying to other crops(wheat, sugarcane, millet). SRI is in progress by evolving and ramifying.
Adaptation to Climate Change:-
Shorter duration and suitability to fit into changes in water availability periods.
Water saving at the farm level –mainly due to controlled irrigation and alternate wetting and drying (water scarce areas).
Tolerance to abiotic (drought, heat waves, cold snaps, winds) and biotic (pest and diseases) stresses.
Increase in productivity.
Mitigation of Climate Change:-
•Methane emission from rice fields are determined mainly by water regime and organic inputs.
•Flooding causes methane emission -organic inputs stimulate methane emissions as long as fields remain flooded.
•Mid-season drainage and intermittent irrigation can reduce methane emission by 40% (IFPRI 2009).
•Keeping soil nearly saturated conditions may promote N2O release.
•15 to 20% of the benefit gained by decreasing methane emission was offset by the increase of N2O emission.
•Soil organic carbon declines after a shift from flooded system to non-flooded system.
There is nothing magical about SRI; nonetheless, it produces “More Output with Less Inputs.” Hence, it is a resource-conserving technique of rice production that is good for farmers, consumers, and the environment.
Suraj Poudel, BSc. Ag 14th batch (IAAS,TU)