Department of Land Resource Management, Shanxi University of Finance and Economics, Taiyuan 030006, China; Land Reclamation Center for Mining Area, Shanxi University of Finance and Economics, Taiyuan 030006, China.
Department of Land Resource Management, Shanxi University of Finance and Economics, Taiyuan 030006, China; Land Reclamation Center for Mining Area, Shanxi University of Finance and Economics, Taiyuan 030006, China.
Sci Total Environ. 2024 Dec 1;954:176729. doi: 10.1016/j.scitotenv.2024.176729. Epub 2024 Oct 4.
Understanding the influence of microbial taxa and functions on soil carbon (C) and nitrogen (N) cycling, particularly concerning soil aggregate sizes, is crucial for ecosystem management. This study examines the taxonomic and functional dynamics of soil bacterial communities within different aggregate sizes over time. Soil samples from a reclamation forest on the Loess Plateau in North China were collected across reclamation ages of 0, 3, 18, and 28 years. Soil aggregates were categorized into large macro-aggregates (>2000 μm), small macro-aggregates (250-2000 μm), and micro-aggregates (<250 μm) using a modified dry-sieving method. Soil aggregate stability, C and N concentrations, newly derived plant C, enzyme activities, bacterial communities, and functional genes in each aggregate fraction were systematically analyzed. There was a notable increase in soil aggregate stability and a higher proportion of large aggregates was found with increasing forest age. There were significant differences in bacterial community structures, particularly between micro-aggregates and large macro-aggregates and across different forest ages. Reclamation led to an increased abundance of copiotrophic bacterial taxa. Decreases in N-acquiring enzyme activity in micro-aggregates were contrasted by an increase in C, N, and phosphorus (P) acquisition activities in larger aggregates over time. Larger aggregates showed a faster recovery of C and N cycling genes accompanied by a significant enhancement in acetyl-CoA and ammonia oxidation processes, underscoring their importance in soil nutrient cycling. These results highlight the critical role of aggregate size in shaping microbial community structures and functions that influence soil C and N cycling during reclamation and provide new perspectives highlighting the significance of incorporating aggregate size considerations into soil management and reclamation strategies.
了解微生物类群和功能对土壤碳（C）和氮（N）循环的影响，特别是对土壤团聚体大小的影响，对于生态系统管理至关重要。本研究考察了不同团聚体大小范围内土壤细菌群落的分类和功能动态。采集了中国北方黄土高原复垦林不同复垦年限（0、3、18 和 28 年）的土壤样本。采用改良的干筛法将土壤团聚体分为大宏团聚体（>2000μm）、小宏团聚体（250-2000μm）和微团聚体（<250μm）。系统分析了每个团聚体部分的土壤团聚体稳定性、C 和 N 浓度、新衍生的植物 C、酶活性、细菌群落和功能基因。随着林龄的增加，土壤团聚体稳定性显著增加，大团聚体的比例也更高。细菌群落结构存在显著差异，特别是微团聚体和大宏团聚体之间以及不同林龄之间。复垦导致了富养细菌类群丰度的增加。随着时间的推移，微团聚体中 N 获取酶活性的降低与较大团聚体中 C、N 和磷（P）获取活性的增加形成鲜明对比。较大的团聚体表现出更快的 C 和 N 循环基因的恢复，同时伴随着乙酰辅酶 A 和氨氧化过程的显著增强，突出了它们在土壤养分循环中的重要性。这些结果强调了团聚体大小在塑造影响复垦过程中土壤 C 和 N 循环的微生物群落结构和功能方面的关键作用，并提供了新的视角，强调了将团聚体大小考虑因素纳入土壤管理和复垦策略的重要性。
