Effects of controlled-release fertilizer on N 2 O emissions in wheat under elevated CO 2 concentration and temperature

Aims N 2 O emitted by agricultural ecosystems has a great impact on global warming and climate change. The use of controlled-release fertilizers (CRF) can decrease greenhouse gas emissions. However, the general patterns and variability of nitrogen functional genes in response to CRF associated with N 2 O emission have not been synthesized under climate change. Methods We investigated the effects of CRF, elevated CO 2 concentration (EC), elevated temperature (ET), and their combination on N 2 O emission, enzyme activities and gene abundances. Results We found that the cumulative N 2 O emissions was in the range of 0.39–1.65 kg·ha −1 in the wheat-growing season, accounting for 0.54%–2.29% of the total nitrogen input. N 2 O emissions were considerably positively correlated with ammonia-oxidizing bacteria (AOB) at elongation stage. CRF inputs significantly decreased N 2 O emissions by 29 − 66% compared with urea due to decreased AOB abundance and inhibited nitrite reductase activities at elongation stage. EC significantly decreased N 2 O emissions by 30 − 50% likely resulting from the inhibition in nitrifying and denitrifying community compared with ambient CO 2 concentration. ET significantly increased N 2 O emissions by increasing N mineralization in wheat soil under CRF due to higher NH 4 + -N and NO 3 − -N concentration in wheat soil at elongation stage. In addition, ECET had antagonistic effect on N 2 O emissions. CRF had no significant effect on wheat yield under climate change scenarios. Conclusions CRF decreased the cumulative N 2 O emissions under climate change scenarios. This is critical for understanding the responses of N 2 O emissions from wheat soil under CRF to future CO 2 enrichment and warming for the establishment of mitigation and adaptation policies.