In an attempt to stop and reverse soil subsidence in the Delta, rice has been suggested as a crop that could replace corn.  Rice is flooded during the growing season and this action inhibits decomposition of peat. 

Historically, rice was grown north of I80 along the clay soils of the western Sacramento Valley.  The Delta was viewed as too windy and cool to raise rice.  In recent years, new rice cultivars were developed that would grow in the Delta.  We still faced challenges associated with expensive land leveling, many weeds and predation of rice seed by birds.

We collaborated on a USDA and DWR project with UC Davis, Hydrofocus and other groups. We measured methane, carbon dioxide and water vapor fluxes over a rice site for 7 years, 2009-2017, with the eddy covariance method.  The study was conducted on Twitchell Island.

https://ameriflux.lbl.gov/sites/siteinfo/US-twt

The initial study required a closed path methane sensor with a power hungry pump. We did not have AC power at the site, so the site managers ran a diesel generator for us. Towards the end of the study we were able to apply an open path methane sensor that ran off solar panels:

Detto, M., et al. (2011). "Comparing laser-based open- and closed-path gas analyzers to measure methane fluxes using the eddy covariance method." Agricultural and Forest Meteorology 151(10): 1312–1324.

While the rice paddy was generally a net CO2 sink during the growing season, large interannual differences were observed, with the site ranging from a large net CO2 sink in the 2010 growing season (−607 g C-CO2 m−2) to near-CO2 neutral in 2015 (8 g C-CO2 m−2) :

Knox, S. H., et al. (2016). "Biophysical controls on interannual variability in ecosystem-scale CO2 and CH4 exchange in a California rice paddy." Journal of Geophysical Research-Biogeosciences 121(3): 978–1001.

This site was also subject to an oasis effect and experienced evaporation rates that exceed potential evaporation.

Baldocchi, D., et al. (2016). "The impact of expanding flooded land area on the annual evaporation of rice." Agricultural and Forest Meteorology 223: 181–193.