Deng Jiazhen, Hu Jingda, Huang Yongzhen, Wang Shengqiang, Ye Shaoming
Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, Guangxi University, Nanning, China.
Experimental Center of Tropical Forestry, Pingxiang, China.
Front Microbiol. 2024 Jul 22;15:1404428. doi: 10.3389/fmicb.2024.1404428. eCollection 2024.
Soil microbial functional traits are key indicators of soil microbial ecological traits; however, how mixing patterns of Chinese fir and broadleaved trees drive soil microbial functional trait variation at the aggregate scale and how soil microbial functional traits are linked to soil fertility factors have largely not been determined.
In this study, soil from the 0-20 cm depths in three Chinese fir plantations was collected, and the soil samples were separated into >2 mm (large macro-aggregate), 0.25-2 mm (macro-aggregate) and <0.25 mm (micro-aggregate) by complying with an optimal moisture sieving procedure. The metabolic activities, functional diversity and different carbon sources utilization characteristics of the soil microorganisms were determined by the Biolog Eco microplate method.
In all Chinese fir plantations, micro-aggregates (<0.25 mm) consistently exhibited the highest levels of microbial metabolic activity, a more uniform carbon source utilisation capacity, and the highest microbial diversity. Micro-aggregates also showed elevated levels of soil organic carbon (OC), total nitrogen (TN), total phosphorus (TP), and higher ratios of C/N and C/P compared to large macro-aggregates and macro-aggregates, indicating that micro-aggregates contain more resources available to soil microorganisms. Soil OC, TN, and TP content were enhanced by integration with , suggesting that this combination promotes relatively favourable soil conditions for microbial growth and multiplication. This, in turn, promotes microbial metabolic activity. Furthermore, redundancy and correlation analyses showed that soil OC, TN, and TP were identified as principal determinants of soil microbial functional properties in Chinese fir plantations.
In summary, mixed cultivation and aggregate size influenced microbial functional properties via soil nutrient alterations. Consequently, adopting a mixed cultivation approach of Chinese fir and broadleaved trees is advocated in the subtropical regions of Guangxi. Employing a diversity of tree species, including , is recommended for optimal soil quality preservation.
土壤微生物功能性状是土壤微生物生态性状的关键指标；然而，杉木与阔叶树的混交模式如何在团聚体尺度上驱动土壤微生物功能性状变异，以及土壤微生物功能性状如何与土壤肥力因子相关联，在很大程度上尚未确定。
本研究采集了三个杉木人工林0-20厘米深度的土壤，并按照最佳水分筛分程序将土壤样品分离为>2毫米（大团聚体）、0.25-2毫米（团聚体）和<0.25毫米（微团聚体）。采用Biolog Eco微平板法测定土壤微生物的代谢活性、功能多样性和不同碳源利用特征。
在所有杉木人工林中，微团聚体（<0.25毫米）始终表现出最高水平的微生物代谢活性、更均匀的碳源利用能力和最高的微生物多样性。与大团聚体和团聚体相比，微团聚体还表现出更高的土壤有机碳（OC）、总氮（TN）、总磷（TP）水平，以及更高的C/N和C/P比值，表明微团聚体含有更多可供土壤微生物利用的资源。与[具体树种]混交可提高土壤OC、TN和TP含量，这表明这种组合可为微生物生长和繁殖创造相对有利的土壤条件。这反过来又促进了微生物的代谢活性。此外，冗余分析和相关性分析表明，土壤OC、TN和TP被确定为杉木人工林土壤微生物功能特性的主要决定因素。
综上所述，混交栽培和团聚体大小通过土壤养分变化影响微生物功能特性。因此，建议在广西亚热带地区采用杉木与阔叶树的混交栽培方式。为了最佳地保持土壤质量，建议使用包括[具体树种]在内的多种树种。
