坡地的耕种是水土流失的主要原因。保护实践,比如土壤和石头露台,可能会减少侵蚀的影响,但它们对土壤微生物多样性和与碳(C)和养分代谢相关的功能的影响尚不清楚。这项研究是为了评估坡度(5°,8°,15°,25°)和保护实践(栽培,未耕种的,土壤梯田,和石头露台)在细菌和真菌多样性上,与土壤基本特性相关的宏基因组学和代谢组学功能。我们的结果表明,25°的陡坡显着降低了土壤pH值,淤泥百分比,细菌和真菌的丰度,但是土壤和石阶增加了土壤有机碳(SOC),淤泥和粘土含量,与坡耕地相比,真菌丰度。此外,土壤和石阶增加了细菌和真菌的α多样性,和Crenarchoota的相对丰富,Nitrosirota,和Latescibacota,但是减少了放线菌和杆菌的比例,从而改变微生物β多样性,这与SOC和淤泥含量的增加显着相关。对于宏基因组学,土石梯田大大增加了与呼吸相关的功能基因的相对丰度,毒力,疾病与防御,应激反应,氮和钾的代谢,如反硝化和钾稳态。对于土壤代谢组学,共有22种土壤代谢物被土壤和石阶富集,例如脂质和类脂分子(花生四烯酸,γ-亚麻酸,和十五烷酸),和有机杂环化合物(腺嘌呤,Laudanosine,甲基吡嗪,和烟酸)。总而言之,土壤和石阶地可以减少陡坡栽培对土壤微生物多样性的一些负面影响,以及它们与碳和养分代谢有关的宏基因组和代谢组学功能,有助于改善土壤健康,有可能加强世界各地侵蚀热点地区可持续做法的影响。
Cultivation of sloping land is a main cause for soil erosion. Conservation practices, such as soil and stone terraces, may reduce the impacts of erosion but their impacts on soil microbial diversity and functioning related to carbon (C) and nutrient metabolisms remain unclear. This study was conducted to evaluate the effects of slope gradients (5°, 8°, 15°, 25°) and conservation practices (cultivated, uncultivated, soil terrace, and stone terrace) on bacterial and fungal diversities, metagenomic and metabolomic functioning associated with basic soil properties. Our results showed that steep slopes at 25° significantly decreased soil pH, silt percentage, and bacterial and fungal abundances, but that soil and stone terraces increased soil organic C (SOC), silt and clay contents, and fungal abundance compared to sloping cultivated lands. In addition, soil and stone terraces increased both bacterial and fungal alpha diversities, and relative abundances of Crenarchaeota, Nitrospirota, and Latescibacterota, but reduced the proportions of Actinobacteriota and Patescibacteria, thus shifting microbial beta diversities, which were significantly associated with increased SOC and silt content. For metagenomics, soil and stone terraces greatly increased the relative abundance of functional genes related to Respiration, Virulence, disease and defense, Stress response, and nitrogen and potassium metabolisms, such as Denitrification and Potassium homeostasis. For soil metabolomics, a total of 22 soil metabolites was enriched by soil and stone terraces, such as Lipids and lipid-like molecules (Arachidonic acid, Gamma-Linolenic acid, and Pentadecanoic acid), and Organoheterocyclic compounds (Adenine, Laudanosine, Methylpyrazine, and Nicotinic acid). To sum up, soil and stone terraces could reduce some of the negative impacts of steep slope cultivation on soil microbial diversity as well as their metagenomic and metabolomic functioning related to C and nutrient metabolism useful for soil health improvement, potentially bolstering the impact of sustainable practices in erosion hotspots around the world.