SRI 2.0 and Beyond: Sequencing the Protean Evolution of the System of Rice Intensification

As the System of Rice Intensification (SRI) has evolved in many ways and in several directions over the past two decades, this review follows the software-naming convention of labeling SRI's different and subsequent versions as SRI 2.0, 3.0, 4.0, etc. In agroecology as with software, variants are not necessarily linear and can establish new directions as well as the further evolution of existing ones. This overview reviews how rainfed SRI, direct-seeded SRI, mechanized SRI, and other modifications of the initial SRI methodology have emerged since 2000, and how versions of SRI have been improvised to improve the production of other crops beyond rice, like wheat, finger millet, maize, and sugar cane. SRI thinking and practices are also being incorporated into diversified farming systems, broadening the logic and impact of SRI beyond monoculture rice cultivation, and SRI methods are also being used to achieve broader objectives like the reduction of greenhouse gas emissions and the conservation of biodiversity. SRI observations and research have been contributing to the crop and soil sciences by focusing attention on plant roots and soil ecology and by showing how crop management can elicit more desirable phenotypes from a given genotype. Cooperation regarding SRI among farmers, civil-society actors, scientists, private sector agents, governments, and funding agencies has begun introducing noteworthy changes within the agricultural sector, and this collaboration is expected to deepen and expand.