Site observation data on water and carbon flux in farmland located in the middle and lower reaches of Yangtze River, China

The meteorological data, as well as observed soil water content, evapotranspiration, carbon dioxide flux, and methane flux data, were collected from the farmland site. Farmland evapotranspiration and carbon dioxide fluxes were measured using the eddy correlation method, while methane fluxes were measured using the static chamber-gas chromatograph method.