Rice is the main source of directly consumed calories for about half the world’s population and 90% is produced and consumed in Asia. It is estimated that 24-30% of the world’s accessible freshwater resources (rivers, lakes and aquifers) are used to irrigate rice (IWMI 2007). By 2025, 15–20 million of the world’s 79 million hectares of irrigated rice lowlands, which provide three-quarters of the world’s rice supply, are expected to suffer some degree of water scarcity (IWMI 2007). India has the world’s largest rice cultivated area and already faces a major water crisis. Demand for a water-intensive crop such as rice is expected to increase by 38% by 2040, deepening the existing water crisis.
The System of Rice Intensification (SRI) is a set of principles and practices for increasing the productivity of irrigated rice by changing the current conventional management of plants, soil, water and nutrients. The practices include developing nutrient-rich and un-flooded nurseries instead of flooded ones; ensuring wider spacing between rice seedlings; applications of composts or manure rather than synthetic fertilizers; and managing water carefully to avoid saturation of the rice plant’s roots. These practices contribute to both more fertile soil and healthier plants supported by greater root growth and the nurturing of soil microbial abundance and diversity.
SRI methods help increase yields by over 30%, while using 40% less water than conventional methods. The method was initially developed in the 1980s in Madagascar and has been validated in 43 countries. SRI practices and concepts have also been successfully adapted to upland rice and to other crops such as wheat, finger millet, and sugarcane.
Although the benefits of SRI have been amply demonstrated around the world, the potential to achieve these benefits through large-scale implementation of the methods has yet to be tapped. The report More Rice with Less Water recommends that major rice-producing countries, such as India, China and Indonesia, convert at least 25% of their current rice cultivation to SRI methods by 2025. This would not only dramatically reduce the use of water for rice production but also improve global food security.
SRI methods increase the productivity of: