1. Progressing climate change and intensified land-use exert unprecedented pressures on soil microbial communities, thus endangering the essential ecosystem functions they provide. However, these global change factors do not act in isolation from each other, making ecosystem consequences hard to predict.
2. To address this knowledge gap, we tested the interactive effects of climate change and land-use intensity on soil microbial activity, biomass and community composition in a large-scale field experiment. We tested soil microbial responses to a future climate scenario (ambient climate vs. increased temperature by +0.6°C and altered rainfall patterns) in two land-use types (cropland vs. grassland) with two levels of land-use intensity each (high-intensity vs. low-intensity). While high-intensity land-use is characterized by fertilization and pesticide use, low-intensity land-use refrains from both. We measured soil microbial activity and biomass twice per year within a 5-year period and used phospholipid fatty acid analysis to explore changes in microbial community composition.
3. In contrast to our expectations, soil microbes remained largely unaffected by future climate conditions. However, we found evidence that not just the type of land-use, but also their respective management intensity (high vs. low) had strong effects on soil microbes. Low-intensity management promoted soil microbial activity and biomass in grasslands, but this beneficial effect needed several years to establish. Moreover, we show that low-intensity management increased AM fungi and fungal-to-bacterial ratios in croplands as well as grasslands.
4. Our study shows that farmers can promote soil ecosystem functions through low-intensity management measures. In grasslands, low-intensity management measures such as high plant diversity consisting of grasses, forbs and legumes, and no mineral fertilization improve soil microbial activity and biomass, as well as the fungal-to-bacterial ratio. On arable land, compliance with EU organic farming regulations improves the fungal-to-bacterial ratio. We conclude that low-intensity management can have positive effects on efficient carbon storage, nutrient cycling, soil erosion control and ecosystem multifunctionality under different land-use and climate change scenarios.

中文翻译：

---

低强度土地利用可增强当前和未来气候中的土壤微生物活动、生物量和真菌与细菌的比例

1. 不断发展的气候变化和集约化的土地利用对土壤微生物群落施加了前所未有的压力，从而危及它们提供的基本生态系统功能。然而，这些全球变化因素并不是孤立地起作用的，使得生态系统后果难以预测。
2. 为了解决这一知识差距，我们在大规模田间试验中测试了气候变化和土地利用强度对土壤微生物活动、生物量和群落组成的交互影响。我们测试了土壤微生物对未来气候情景（环境气候与温度升高 +0.6°C 和降雨模式改变）的两种土地利用类型（农田与草地）的响应，每种类型具有两个土地利用强度水平（高-强度与低强度）。高强度土地利用的特点是施肥和杀虫剂的使用，而低强度的土地利用则两者兼而有之。我们在 5 年内每年两次测量土壤微生物活动和生物量，并使用磷脂脂肪酸分析来探索微生物群落组成的变化。
3. 与我们的预期相反，土壤微生物在很大程度上不受未来气候条件的影响。然而，我们发现的证据表明，不仅土地利用类型，而且它们各自的管理强度（高与低）对土壤微生物都有很强的影响。低强度管理促进了草地土壤微生物活动和生物量，但这种有益效果需要几年时间才能建立。此外，我们表明低强度管理增加了农田和草地中的 AM 真菌和真菌与细菌的比率。
4. 我们的研究表明，农民可以通过低强度管理措施促进土壤生态系统功能。在草原，低强度的管理措施，如由草、杂草和豆类组成的高植物多样性以及不施肥，提高了土壤微生物活性和生物量，以及真菌与细菌的比例。在耕地上，遵守欧盟有机农业法规可提高真菌与细菌的比例。我们得出的结论是，在不同的土地利用和气候变化情景下，低强度管理可以对有效的碳储存、养分循环、土壤侵蚀控制和生态系统多功能产生积极影响。