What is different about SRI
What is different about System of Rice Intensification (SRI) ?
In SRI the saplings are carefully transplanted singly, rather than in clumps, at the age of 8 to 12 days, which is a quarter of the age of saplings being transplanted according to the conventional method. They need to be spaced wide apart (25cm X 25cm) in square pattern rather than in rows. This gives the roots ample space to grow. Initially, farmers are reluctant to adopt these steps, believing that saplings are not strong enough, but early and careful transplantation allows for better tillering, ensuring that the rice plants have stronger, denser tufts and multiple seed heads.
Farmers then have to weed their fields four times over the course of the season using a simple rotary hoe to aerate the soil and control the weeds. Weeding and aeration are required because in SRI there is no flooding of fields, where standing water usually works as weed control. The simple mechanical weeder churns the soil, removing the competition for the soil’s nutrients and providing the young rice plant’s roots with additional oxygen and nitrogen due to the additional microbial activity. This new step, despite being particularly labour intensive has high payoffs, with an increase in yield of up to 2tonnes/ha/weeding. In addition, organic compost or manure improves the soil’s health and structure, provides the plant with more balanced nutrition and so, naturally, increases plant growth.
Finally, with SRI, rice fields require just enough water to keep the soil moist but not saturated, with intermittent drying periods for aerobic and anaerobic soil conditions to maintain healthy soil biota. With the introduction of the rotary weeder, and periods of intermittent wetting and drying, farmers benefits considerable water savings, sometimes up to 40%. This is a considerable benefit, especially in drought or water scarce areas.