Soil carbon (C) storage is a critical ecosystem function that underpins human health and well-being. The acceleration of human-driven land use change, such as agricultural intensification, is a major driver of soil C loss globally. Developing sustainable land use practices that enhance agricultural productivity whilst protecting essential ecosystem functions such as soil C storage is vital. The soil microbiome has a critical role in regulating soil biogeochemical cycling processes, including soil C cycling. Examining the impacts of land use intensity on the soil microbiome enables us to assess the potential effects on long-term soil C stocks. Using metagenomic DNA sequencing and phospholipid fatty acid analysis, we investigated differences in the activity, diversity, and function of the soil microbiome associated with five contrasting land uses across an agricultural landscape. The land uses covered a gradient of disturbance intensities and included remnant native forest, regenerating native bush, exotic plantation forest, dryland pasture, and irrigated pasture. We identified pronounced differences in the soil microbiome associated with each land use, including the diversity and abundance of microbial C and nitrogen (N) cycling genes. Notably, intensive agricultural land uses had a significantly higher diversity and abundance of microbial C-degrading genes, whilst land uses of remnant native forest had the lowest diversity and abundance of microbial C-degrading genes. Our findings suggest that intensive agricultural land use may increase the functional potential of the soil microbiome to mineralize soil C, potentially resulting in a greater loss of soil C as respired CO into the atmosphere. This research may be used to support the development of sustainable management practices that promote the persistence of soil C across agricultural landscapes, such as the protection of remnant native forest fragments and greater incorporation of regenerating native vegetation.

中文翻译：

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土地利用强度是整个农业景观土壤微生物和碳循环的主要驱动因素


土壤碳（C）储存是支撑人类健康和福祉的重要生态系统功能。人类驱动的土地利用变化的加速，例如农业集约化，是全球土壤碳流失的主要驱动因素。制定可持续的土地利用做法，提高农业生产力，同时保护土壤碳储存等基本生态系统功能至关重要。土壤微生物组在调节土壤生物地球化学循环过程（包括土壤碳循环）中发挥着关键作用。研究土地利用强度对土壤微生物组的影响使我们能够评估对长期土壤碳储量的潜在影响。利用宏基因组 DNA 测序和磷脂脂肪酸分析，我们研究了与农业景观中五种不同土地利用相关的土壤微生物组的活性、多样性和功能差异。土地利用涵盖了干扰强度的梯度，包括残余的原生森林、再生的原生灌木、外来人工林、旱地牧场和灌溉牧场。我们发现了与每种土地利用相关的土壤微生物组的显着差异，包括微生物 C 和氮 (N) 循环基因的多样性和丰度。值得注意的是，集约化农业用地的微生物碳降解基因的多样性和丰度显着较高，而残余原生林的土地利用的微生物碳降解基因的多样性和丰度最低。我们的研究结果表明，集约化农业用地可能会增加土壤微生物组矿化土壤碳的功能潜力，从而可能导致土壤碳随着呼吸二氧化碳进入大气而大量流失。 这项研究可用于支持可持续管理实践的发展，以促进农业景观中土壤碳的持久性，例如保护残余的原生森林碎片和更多地纳入再生原生植被。