Increased nitrogen availability alters soil carbon quality by regulating microbial r‐K growth strategy, metabolic efficiency, and biomass in degraded temperate grasslands
Increased nitrogen availability alters soil carbon quality by regulating microbial r‐K growth strategy, metabolic efficiency, and biomass in degraded temperate grasslands
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DOI：
10.1002/ldr.3943
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发表时间：
2021-03
影响因子：
4.7
通讯作者：
Wenjing Zeng;Zhaodi Wang;Xinyue Chen;Xiaodong Yao;Wei Wang
中科院分区：
文献类型：
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作者：
Wenjing Zeng;Zhaodi Wang;Xinyue Chen;Xiaodong Yao;Wei Wang
土壤微生物r-K生长策略、代谢效率和生物量在大气氮沉降情景下调节土壤碳质量的作用的实验证据有限，特别是在退化草地中。在这里，土壤样品收集了非，中度，严重和极端退化草原在内蒙古，中国的四个地点。土壤培养200天与N添加处理。测量土壤CO2-C释放速率，以拟合三库模型，通过快速、慢速和被动C组分的库大小来描述土壤C质量。测定了土壤微生物r-K生长策略、代谢效率、生物量和主要非生物因子。在非退化草地中，N的添加显著增加了快速C库的大小，但主要通过增加微生物生物量N降低了慢速C库的大小。然而，在所有三种退化草地中，通过改变微生物r-K生长策略、代谢效率和生物量，观察到不同C库大小与N添加之间的一致模式：快速C库大小保持相对稳定，因为r-策略增加和代谢效率提高的对比效应;微生物代谢效率和微生物生物量N的组合积极影响增加了缓慢C库的大小，而被动C库的大小出乎意料地减少，尽管代谢效率，微生物生物量N，战略家也增加了这些发现突出了微生物r-K生长策略，代谢效率和生物量的变化在调节退化温带草原土壤C质量中的重要作用。
Experimental evidence is limited for the role of soil microbial r‐K growth strategy, metabolic efficiency, and biomass in regulating soil carbon (C) quality under the atmospheric nitrogen (N) deposition scenario, especially in degraded grasslands. Here, soil samples were collected from four sites with non, moderately, severely, and extremely degraded grasslands in Inner Mongolia, China. The soil was incubated for 200 days with N addition treatment. Soil CO2‐C release rates were measured to fit a three‐pool model for describing soil C quality by the pool sizes of the fast, slow, and passive C fractions. Soil microbial r‐K growth strategy, metabolic efficiency, biomass, and major abiotic factors were measured. In non‐degraded grasslands, N addition significantly increased the fast C pool size but decreased the slow C pool size primarily through increases in microbial biomass N. However, in all three degraded grasslands, a consistent pattern was observed among different C pool sizes with N addition through changes in microbial r‐K growth strategy, metabolic efficiency, and biomass: the fast C pool size remained relatively stable because of the contrasting effects of increases in r‐strategists and enhanced metabolic efficiency; the slow C pool size was increased by the combined positive impacts of microbial metabolic efficiency and microbial biomass N and the passive C pool size decreased unexpectedly, although the metabolic efficiency, microbial biomass N, and r‐strategists increased. These findings highlight the important role of changes in microbial r‐K growth strategy, metabolic efficiency, and biomass in regulating soil C quality in degraded temperate grasslands.