(disclaimer that I manage a climate group, but not a rice expert)
They touch on, but don't get into the details on one of the more interesting aspects of perennial rice.
Rice fields are actually a huge emitter of methane. Depending on the accounting, they contribute as much to global warming as the aviation sector.
The fields emit methane when flooded, the stagnant water gets oxygen depleted, and the biomass in the soil degrades. This flooding is mostly used to control for weeds, but weeds have a much more difficult time competing when a perennial canopy already exists.
So, perennial rice may end up reduce GHG emissions substantially.
They touch on, but don't get into the details on one of the more interesting aspects of perennial rice.
Rice fields are actually a huge emitter of methane. Depending on the accounting, they contribute as much to global warming as the aviation sector.
The fields emit methane when flooded, the stagnant water gets oxygen depleted, and the biomass in the soil degrades. This flooding is mostly used to control for weeds, but weeds have a much more difficult time competing when a perennial canopy already exists.
So, perennial rice may end up reduce GHG emissions substantially.