Actual practices developed in California?

“There are three practices we’ve included in the methodology.”

  • Reduction of winter flood.

“We actually put a restriction on that to only allow a 10 percent reduction in the overall area that is flooded. That’s because the winter flooding in California provides important habitat for migratory birds – waterfowl and other birds that come through in the winter season.

“In the project, we’re working with the Point Reyes Bird Observatory to analyze if 10 percent is the right number. So, we’ll be revisiting that percentage for that particular practice.

“Reduced winter flooding can lower methane emissions by around 16 percent.”

Morris points out the percentage reductions offered for the various practices “are estimates and dependent on a number of conditions in the field.”

  • Dry seeding.

“This is going in and seeding when the field is dry rather than when it’s wet. That lowers methane emissions around 4 percent.”

  • Removal of straw at harvest’s end.

“This is taking the straw off the field, baling and selling it. This is done rather than incorporating the straw into the soil before flooding it. That produces lower methane emissions.

“Baling the straw can produce around an 8 percent reduction in methane emissions.”

Any other practices you will research?

“Another practice we’ve looked at -- that we didn’t validate because in California it isn’t really a viable practice -- is mid-season drainage. Mid-season drainage is basically draining the field during a critical time during the growing season for a certain period of time.

“But it is a risk for (California) rice farmers because if the temperatures get too cold at night the plant can be sterilized. In California, where there are a lot of cold nights, it’s too risky and the potential yield loss is too great.

“In addition, in California, the fields are large and moving the water on and off is more complicated.

“During the previous project with USDA funding, we did a (mid-season drainage) trial with a farmer on a small field, about 27 acres. The yield loss was negligible, so low you wouldn’t necessarily attribute it to the practice. But there hasn’t been the scientific measurements done to sufficiently validate the model so it could be included in the methodology.

“However, in the Mid-South where temperatures are warmer, we think that could be a valid practice. And you actually get a bigger methane reduction from mid-season drainage.”

On other potential practices…

“In California, they dry down the fields about five days before harvest. By taking the flood away for a longer period – maybe up to 15 days before harvest – there is a methane emission reduction.

“Also, in California, a lot of fields have already been laser-leveled. In the Mid-South fewer fields have been. Laser-leveling of fields can also produce a reduction in methane emissions and, potentially, water savings.

“Another option is to look at rice varietals that produce lower methane emissions.”