Himalayan Permaculture Centre (HPC)
SRI Rice Cultivation
One of the most pressing needs of the day and indeed the future is how to feed the increasing global population. Scientists, trans-global corporations and governments often tout high-input, high-technology means of attempting this. However not only the ethics of these attempts are questionable, but also their sustainability, especially in light of recent increases in oil prices that directly affect both manufacture and transport of agro-chemicals, further increasing the cost to farmers.
So when a technique comes along that is so common sense, involving only extra inputs of information, yet which can organically improve production of the world's most grown crop (and thus affect hundreds of millions of farmers), it is surely time to look up.
SRI, the System of Rice Intensification, is one such example. More than a technique, where a+b=c, it is a set of principles, a system which leads to a set of practices that are varied according to local conditions. It has developed from attempts to study and correct certain situations with conventional, traditional rice growing. These are:
1. If the rice plant is disturbed during crucial growth stages (as it is when it is transplanted), this has long-term effects on the plant's productivity.
2. The flooding of rice leads to oxygen-starvation on the roots, which can cause up to 75% root death and so greatly reduces capacity for nutrient uptake.
3. Rice plants transplanted in bunches of 3-6 plants with bunches planted close together suffer from competition for nutrients and light. When the canopy closes in the rice paddy, the understorey is so dark lower leaves cannot photosynthesise, so don't contribute to the growth of the plant or grain.
SRI looks more at root-soil relationships to create the healthiest conditions for plants to grow in. As such, organic methods are more suitable, evolving around plenty of compost in the soil and a vibrant soil life.
SRI involves four major changes from conventional rice production:
1. The seedlings grown in the nursery beds are transplanted after just 8-12 days, or at the 2-leaf stage (cooler/upland areas may take longer, but it's still at the 2-leaf stage).
2. Seedlings are transplanted singly, not in a bunch.
3. Seedlings are transplanted at a wide spacing, from 20 to 40 cm apart.
4. Much less water is kept on the paddies, and the soil is allowed to dry out (“crack”) from time to time.
The test is in the yield. Paddy managed under SRI has shown good increases in yield. Double yields are not difficult to achieve, and some farmers have achieved up to 4 times their normal yield.
The benefits are:
• rice production increased (over 16T/Ha has been documented)
• less water needed (around 15-25% of normal practice)
• less seed needed (about 12% of normal practice)
• no extra external inputs needed
• can use local/traditional seed
• due to better soil and water management there are:
- less pests and disease
- better quality grains
- more fertile soils
- more straw
Globally SRI application has grown exponentially over the past few years in particular, with scientific analyses mapping significant increases in yield as well as soil quality. See http://sri.cals.cornell.edu/ for more details.
SRI – an approach to growing rice whose time has surely come