土壤磷含量与有效性对N2O排放量的影响元分析

土壤氧化亚氮(N₂O)主要产生于土壤微生物参与的氮循环过程，其排放量受磷含量及有效性影响。添加磷肥有助于缓解陆地生态系统磷限制，提升土壤有效磷含量，进一步影响土壤微生物对氮的利用，同时控制N₂O排放。然而不同独立实验中N₂O对外源磷添加的响应差异较大。研究从发表的中、英文文献中收集了54份关于施用磷肥与N₂O排放量的观测结果，采用元分析方法确定添加外源磷后N₂O排放量的响应差异及潜在影响因素。结果表明：(1)外源磷添加对土壤N₂O排放量影响不显著；但在磷肥施用量> 50 kg P/hm²的室外实验中土壤N₂O排放量显著降低了32.5%;施用NaH₂PO₄的室内实验中N₂O排放量显著降低了18.4%。(2)土壤N₂O对外源磷添加响应的高变异性是磷肥施用量和土壤含水量、土壤pH、土地利用类型、磷肥种类、纬度和实验时间多种影响...

Effects of soil phosphorus concentration and availability on N2 O emissions: a meta-analysis

Soil nitrous oxide (N₂O) is produced primarily by nitrogen cycling processes involving soil microbes, and its emission is affected by phosphorus concentration and availability. The application of phosphorus fertilizer contributes to alleviating phosphorus limitation in the terrestrial ecosystems. It enhances soil available phosphorus concentration, which further affects nitrogen utilization by soil microbes and controls N₂O emissions. However, the response of N₂O to exogenous phosphorus addition varied widely in independent experiments. In this study, 54 observations on phosphorus fertilizer application and N₂O emissions were collected from the published Chinese and English literature, and a meta-analysis was used to determine the differences in response and potential influencing factors of N₂O emissions after applying exogenous phosphorus. The results are as follows. (1) The effect of exogenous phosphorus addition on soil N₂O emissions was not significant. However, soil N₂O emissions were significantly reduced by 32.5% in the outdoor experiments with the application of phosphorus fertilizer > 50 kg P/hm². And soil N₂O emissions were significantly reduced by 18.4% in the indoor experiments with the application of NaH₂PO₄. (2) The high variability of soil N₂O response to exogenous phosphorus addition was the result of the combined effect of various influencing factors such as phosphorus fertilizer application rate and soil moisture, soil pH, land use type, phosphorus fertilizer type, latitude, and experimental time. (3) The regression coefficients of total phosphorus and available phosphorus in the regression analysis of outdoor and indoor experiments were -1.433 (P<0.001) and -0.043 (P<0.001), respectively, and the N₂O emission had a decreasing trend with the increase of phosphorus concentration. These results implied that identifying the relationship between soil phosphorus and N₂O could provide new insights for understanding elemental biogeochemical cycles and mitigating global warming.