Using a technique deriving from work started in the 1960s by a French priest, Henri de Laulanié, in Madagascar, farmers in many developing countries have increased their paddy field rice yields by 50 to 100% – and often much more.
The worldwide average rice yield is about 4 tonnes per hectare. Using modern fertilizers and practices, this can be increased up to about 8 tonnes per hectare. The System of Rice Intensificatation (SRI) has produced much better yields – up to a record of 22.4 tonnes per hectare – in countries around the world, including India, Pakistan, Indonesia, Cambodia, Afghanistan, Brazil, Iran, Cuba and even Mali, on the edge of the Sahara. And SRI uses 80-90% less seed, 25-50% less water and little or no inorganic fertilizer.
As well as accounting for as much as a third of the world's entire fresh water consumption, conventional flooded rice paddies provide ideal anerobic conditions for microbes which produce 13% of global methane emission.
SRI has six key elements:
- Seedlings are planted at a much younger age
- Only a single seedling, instead of a handful of seedlings, is planted at each point
- Plants are placed much wider apart – usually in a 25 centimetre grid pattern
- Water is applied intermittently to create wet and dry soil periods, instead of continuous flooding
- Weeds are controlled by rotary weeding and
- Organic fertilizers, particularly compost, are used.
The wider spacing of plants gives them better access to sunlight and soil nutrients, producing larger, healthier plants. Intermittent irrigation causes soils to crack, which promotes soil aeration whereas flooding causes root degeneration through lack of oxygen.
Similar techniques of crop intensification have been tried, with promising results, for wheat, sugarcane, mustard, millet, legumes and teff (a grain widely cultivated in Ethiopia and Eritrea).