Microbial carbon use efficiency in grassland soils subjected to nitrogen and phosphorus additions
Microbial carbon use efficiency in grassland soils subjected to nitrogen and phosphorus additions
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DOI：
10.1016/j.soilbio.2020.107815
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发表时间：
2020-07
影响因子：
9.7
通讯作者：
M. Widdig;P. Schleuss;L. Biederman;E. Borer;M. Crawley;K. Kirkman;E. Seabloom;P. D. Wragg;M. Spohn
中科院分区：
文献类型：
--
作者：
M. Widdig;P. Schleuss;L. Biederman;E. Borer;M. Crawley;K. Kirkman;E. Seabloom;P. D. Wragg;M. Spohn
土壤微生物碳利用效率（CUE）是土壤微生物碳利用效率的一个重要指标，是研究陆地生态系统碳循环的关键。土壤微生物CUE被认为是增加氮（N）添加，从而介导大气氮沉降对土壤中的C循环的影响。研究了来自南非、美国和英国的6种草地土壤中氮、磷以及氮磷复合添加对土壤微生物CUE的影响。微生物CUE在25%和57%之间变化，所有部位、深度增量和治疗的平均值为40%。大部分的网站变异微生物CUE解释砂含量，年平均降水量和温度，溶解有机碳：溶解氮的比例。土壤微生物CUE以及微生物生物量周转时间是强大的N，P和NP供应的变化。然而，施氮显着降低了表土微生物呼吸和C吸收。两者合计，N，P，NP添加并没有影响微生物CUE和生物量周转时间在不同大陆的草地土壤，表明微生物CUE变化不大，尽管元素输入的变化很大。因此，增加氮输入土壤可能有一个较小的影响微生物CUE和生物量周转时间，因此在草原土壤中的C循环，比预期和模型假设CUE增加，增加氮输入可能高估未来的C存储。
Soil microbial carbon use efficiency (CUE), defined as the ratio between carbon (C) allocated to growth and C taken up by microorganisms, is pivotal for the understanding of C cycling in terrestrial ecosystems. Soil microbial CUE is thought to increase under nitrogen (N) addition, thereby mediating the effects of atmospheric N deposition on C cycling in soils. We studied the effects of N, phosphorus (P), and combined N and P addition on soil microbial CUE from a total of six grassland soils from South Africa, USA, and UK. Microbial CUE varied between 25 and 57% with a mean value of 40% across all sites, depth increments, and treatments. Most of the site variability in microbial CUE was explained by sand content, mean annual precipitation and temperature, and the dissolved organic C:dissolved N ratio. Soil microbial CUE as well as microbial biomass turnover time were robust to changes in N, P, and NP supply. However, N addition significantly reduced microbial respiration and C uptake in the topsoil. Taken together, N, P, and NP addition did not influence microbial CUE and biomass turnover time in grassland soils on different continents, indicating that microbial CUE varies little despite large changes in element inputs. Consequently, increased N inputs to soil may have a smaller impact on microbial CUE and biomass turnover time, and therefore C cycling in grassland soils, than expected and models assuming increased CUE with increasing N inputs could overestimate future C storage.