Differential responses of system of rice intensification (SRI) and conventional flooded-rice management methods to applications of nitrogen fertilizer
Rising food demand, slowing productivity growth, poor N-use efficiency in rice, and environmental degradation necessitate the development of more productive, environmentally-sound crop and soil management practices. The system of rice intensification (SRI) has been proposed as a methodology to address these trends. However, it is not known how its modified crop-soil-water management practices affect efficiency of inorganic nitrogen applications.
Field experiments investigated the impacts of SRI management practices with different N-application rates on grain yield, root growth and activity, uptake of N and its use-efficiency, leaf chlorophyll content, leaf N-concentration, and photosynthetic rate in comparison with standard management practices for transplanted flooded rice (TFR).
Overall, grain yield with SRI was 49 % higher than with TFR, with yield enhanced at every N application dose. N-uptake, use-efficiency, and partial factor productivity from applied N were significantly higher in SRI than TFR. Higher leaf nitrogen and chlorophyll contents during the ripening-stage in SRI plants reflected delayed leaf-senescence, extension of photosynthetic processes, and improved root-shoot activities contributing to increased grain yield.
Rice grown under SRI management used N fertilizer more efficiently due to profuse root development and improved physiological performance resulting in enhanced grain yield compared to traditional flooded rice.
KeywordsCultivation practices Grain yield Nitrogen use efficiency Oryza sativa Root growth System of rice intensification
System of rice intensification
Transplanted flooded rice
Alternate wetting and drying
Agronomic nitrogen use efficiency
Partial factor productivity
The authors wish to thank Prof. Norman Uphoff, Senior Advisor for the SRI International Network and Resources Center (SRI-Rice), Cornell International Institute for Food, Agriculture and Development, Ithaca, NY, USA, for reviewing drafts of this manuscript and offering useful comments. We also deeply thank the anonymous reviewers for their very constructive comments.
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