Mushroom residue application affects CH4 and N2O emissions from fields under rice–wheat rotation

A field experiment involving rice–wheat rotation was performed to investigate the effect of mushroom residue (MR) in comparison with chemical fertilizer (CF) and crop straw return on methane (CH4) and nitrous oxide (N2O) emissions in 2012–2013. Five treatments in quadruplicate were included in this study: (1) CF only, (2) CFS (straw + CF), (3) MR-1 (50% amount of N in CF was replaced with MR), (4) MR-2 (100% amount of N in CF was replaced with MR) and (5) MR-3 (150% amount of N in CF was replaced with MR). Results showed that the effects of CFS and MR-1 treatments on CH4 and N2O emissions did not significantly differ. By contrast, CH4 emissions decreased as the amount of applied MR increased. Crop straw and MR stimulated CH4 emissions (from 48.8% to 119%) in rice season in 2012. In 2013, the applied crop straw and MR decreased CH4 emissions (from 21.3% to 37.3%). This contrasting effect might be explained by the difference in soil moisture content between the two seasons. N2O emission in wheat season could be efficiently decreased (from 25.2% to 29.7%) by applying MR. Our results suggesting that MR could be used as a soil organic amendment under the premise of proper water management.