ABSTRACT
Flooded rice cultivation emits significant quantities of methane (CH4) produced by microbial, anaerobic decay of organic matter, contributing about 20% of the global CH4 budget. The presence of algae on the surface of a flooded soil may also affect CH4 emission because of the release of oxygen (O2) during algal photosynthesis. This chapter describes greenhouse and laboratory experiments with the initial objectives of evaluating: the effects of rice plant development stage on CH4 emission; methane entrapment in the soil profile; and the effects of living rice plants roots on soil Eh. The soil used for the experiment was a silt loam soil sampled from Crowley, Louisiana, USA. Transparent PVC containers were used as soil microcosms. The greenhouse experiment consisted of two treatments: with rice and without rice. Methane emission decreased substantially in the presence of a thin layer of algae in microcosms without rice plants.
