Changes in precipitation frequency and intensity are predicted to be more intense and frequent accompanying climate change and may have immediate or potentially prolonged effects on soil CO₂ and CH₄ fluxes. However, how soil CO₂ and CH₄ fluxes respond to change in precipitation patterns remains poorly understood, especially under nitrogen (N) addition. In this study, we investigated the fluxes of soil CO₂ and CH₄ during a two-year field experiment and the effects of long-time precipitation reduction (− 30% of through-fall), short-term precipitation pulse and change of snow thickness on their response to simulated N deposition (50 kg N hm⁻² y⁻¹). Soil CO₂ flux was greater enhanced by N addition in the relatively wet growing season (2016) than in the relatively dry growing season (2017), whereas soil CH₄ flux was more inhibited by N addition in the relatively wet growing season 2016 than in the relatively dry growing season 2017. However, reduced precipitation decreased the positive effect of N addition on soil CO₂ flux in the relatively wet growing season 2016, while changing the direction of N addition effect in the relatively dry growing season 2017. These results suggested that the precipitation patterns in the growing season may affect soil CO₂ and CH₄ fluxes response to N addition. Furthermore, we found that short-term extreme precipitation and thickness of snow cover had a significantly positive effect on soil CH₄ flux but had a significantly negative effect on soil CO₂ flux. The extreme precipitation, that is, very heavy precipitation, reduced the response magnitudes of soil CO₂ and CH₄ fluxes to reduced precipitation within 3 days, compared to wet precipitation and heavy precipitation. Our results indicated the significant effects of precipitation pattern changes on responses of soil C flux to N deposition, which should be incorporated into the global-C-cycling models to improve the prediction and reduce the uncertainty of C-climate feedbacks.

预计降水频率和强度的变化将伴随气候变化而更加剧烈和频繁，并且可能对土壤CO ₂和CH ₄通量产生直接或潜在的影响。然而，土壤CO ₂和CH ₄通量如何响应降水模式的变化仍然知之甚少，尤其是在添加氮（N）的情况下。在这项研究中，我们调查了为期两年的野外试验期间土壤CO ₂和CH ₄的通量，以及长期降水减少（通降的-30％），短期降水脉冲和降雪的影响。厚度对模拟氮沉降的响应（50 kg N hm ^-2 y ^-1）。与相对干旱的生长季节（2017）相比，在相对湿润的生长季节（2016）土壤中CO _2的通量更大程度地增加了氮，而在2016年相对较湿的生长季节，土壤CH _4的通量被氮的添加更多地受到了抑制。 2017年相对干燥的生长季节。然而，降水减少降低了2016年相对潮湿的生长季节中N添加对土壤CO ₂通量的积极影响，同时改变了2017年相对干燥的生长季节中N添加影响的方向。这些结果表明生长季节的降水方式可能影响土壤CO ₂和CH ₄通量对氮添加的响应。此外，我们发现短期极端降水和积雪厚度对土壤CH ₄通量具有显着的正效应，但对土壤CO ₂通量具有显着的负效应。与湿式降水和强降水相比，极端降水（即非常强的降水）在3天内降低了土壤CO ₂和CH ₄通量对降水减少的响应幅度。我们的结果表明降水模式变化对土壤碳通量对氮沉降响应的显着影响，应将其纳入全球碳循环模型以改善预测并减少碳气候反馈的不确定性。