Schematic diagram contrasting the major variations in rice cultivation systems, including dry and wet field types. The diagram represents schematically variation the extent of standing water and rainfall through the rice growth cycle. Indicated across the bottom of the diagram are expected methane and grain output trends. In addition the earliest regimes inferred for various regions are indicated (based on discussions in Castillo and Fuller, 2010; Fuller and Qin, 2009; and this article)