Soil microbial communities play a crucial role in the accumulation and stabilization of soil organic carbon (SOC) through complex processes involving plant residue transformation and mineral interactions. These processes are influenced by plant inputs and modulated by soil properties that are mostly determined by the parent material. However, our understanding is limited regarding the manner in which vegetation and parent material affect microbial community structure, necromass accumulation, and their subsequent impact on SOC storage. To bridge this knowledge gap, we conducted an in-depth investigation focusing on the top-down influence of vegetation type and the bottom-up effect of parent material on microbial-mediated carbon transformation across soil profiles in a tropical region. Our study encompassed 42 sites on three parent materials (basalt, granite, and marine sediments) and four vegetation types (rubber, banana, areca plantations and uncultivated grassland). Soil samples were collected at 0–20, 20–40, 40–80, and 80–100 cm depth. Microbial community structure and necromass were quantified using microbial biomarkers of phospholipid fatty acids and amino sugars, respectively. In rubber plantations, we observed a trend toward higher microbial biomass that, though not significant when compared to other vegetation types, transformed to a significantly higher accumulation of microbial necromass. This increase in microbial necromass was linked to the accumulation of SOC facilitated by the presence of clay size minerals in clayey soils developed from basalt. In particular, basaltic soils were dominated by bacteria, which facilitated the accumulation of bacterial necromass that significantly bolstered its contribution to SOC. In contrast, in sandier soils developed from granite and marine sediments, fungal communities and necromass dominated due to the propensity of fungi for coarser soil environments. Overall, the main impact of vegetation on microbial communities and necromass accumulation was primarily demonstrated for the topsoil. Differences in soil texture arising from different parent materials exert significant effects on the fungal-to bacterial-biomass and necromass ratios, consequently influencing the contribution of fungal and bacterial necromass carbon to SOC across soil profiles. Our study underscores the pivotal role of parent material in governing tropical profile-scale soil carbon storage by shaping the structure of microbial communities and influencing the retention of microbial necromass.

中文翻译：

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土壤碳储存：母质和植被对剖面尺度微生物群落结构和坏死物积累的影响

土壤微生物群落通过涉及植物残体转化和矿物质相互作用的复杂过程，在土壤有机碳（SOC）的积累和稳定中发挥着至关重要的作用。这些过程受到植物输入的影响，并受到土壤特性的调节，而土壤特性主要由母质决定。然而，我们对植被和母质影响微生物群落结构、坏死物积累及其对 SOC 储存的后续影响的了解有限。为了弥补这一知识差距，我们进行了深入调查，重点关注植被类型自上而下的影响和母质对热带地区土壤剖面微生物介导的碳转化的自下而上的影响。我们的研究涵盖了 42 个地点，涉及三种母质（玄武岩、花岗岩和海洋沉积物）和四种植被类型（橡胶、香蕉、槟榔种植园和未开垦的草地）。土壤样品采集深度为 0-20、20-40、40-80 和 80-100 厘米。分别使用磷脂脂肪酸和氨基糖的微生物生物标志物对微生物群落结构和坏死物进行量化。在橡胶种植园中，我们观察到微生物生物量较高的趋势，尽管与其他植被类型相比并不显着，但转化为微生物坏死物积累量明显较高。微生物坏死物的增加与 SOC 的积累有关，而 SOC 的积累是由玄武岩形成的粘土中粘土尺寸矿物的存在所促进的。特别是玄武岩土壤以细菌为主，这促进了细菌坏死物的积累，从而显着增强了其对 SOC 的贡献。相比之下，在由花岗岩和海洋沉积物形成的沙质土壤中，由于真菌倾向于较粗糙的土壤环境，真菌群落和死灵体占主导地位。总体而言，植被对微生物群落和坏死物积累的主要影响主要体现在表土上。不同母质引起的土壤质地差异对真菌与细菌生物量和死物的比率产生显着影响，从而影响真菌和细菌死物碳对整个土壤剖面的 SOC 的贡献。我们的研究强调了母质通过塑造微生物群落结构和影响微生物坏死物的保留来控制热带剖面尺度土壤碳储存的关键作用。