[Effects of straw mulching on CO2 flux in wintry fallow paddy field].

This paper studied the effects of straw mulching on the CO2 flux in a wintry fallow paddy field at Taoyuan Agro-ecological Station, Chinese Academy of Sciences. The results showed that the effects of straw mulching mainly exerted in two ways. First, it positively affected soil temperature, making the CO2 flux increased obviously. Straw mulching gave a net emission of 2.68 g CO2 x m(-2) x d(-1), while no mulching gave a net fixation of 1.99 g CO2 x m(-2) x d(-1), the difference between them being very significant (P < 0.01). Second, straw mulching decreased the biomass of weeds and the photosynthetically active radiation they absorbed, which in turn resulted in an increase of CO2 flux. Under straw mulching, the water content in surface soil layer (0-15 cm) increased by 9% or more, but no significant change was observed in CO2 flux.