What's the difference between dry seeded rice (DSR) and aerobic rice?

The answer to this question depends a lot on what is meant by both terms—dry seeded rice (DSR) and aerobic rice.

It is difficult to give a simple answer to the question. The bottom line is that we need to carefully define what we are talking about when we use each term:

Shades of grey and clear definitions

Whether dry seeded rice is the same as aerobic rice or not depends on how the water is managed—if a significant proportion of the root zone soil dries below saturation for a significant period of time. But what proportion of the root zone are we talking about, and for what period of time?

  • When grown in the monsoon season on clay soils, dry seeded rice is likely to be flooded or the soil saturated much of the time, and is not aerobic.
  • When grown in the dry season on a sandy loam soil with only a few irrigations or in a low rainfall environment, it could be called aerobic.
  • But when grown in the dry season with frequent AWD events, it is somewhere in between these extremes.

Thus it is not helpful to debate about whether the production system is aerobic or not, whether or not dry seeded rice and aerobic rice are the same thing or not, nor what the differences are.

The important thing is to clearly define the system you are talking about—which means defining three things—the planting or crop establishment method, the land preparation or tillage management, and the water management.

The term DSR is already being widely used in irrigated areas across India, by farmers as well as extensionists and scientists, to imply a combination of crop establishment method and alternate wetting and drying water management. This meaning of DSR in India, and probably South Asia as a whole, is here to stay.