Soil organic matter (SOM) is important in maintaining soil fertility and other ecosystem functions. Yet, land management in intensive agriculture has caused SOM level to decrease, with knock-on effects for soil fertility and quality. Therefore, land management options that ensure that SOM is not depleted and that soil functions are better sustained are of increasing interest. However, there is limited knowledge on how different land managements affect the composition of SOM and associated microbial functional profiles. Twelve long-term field experiments, covering a wide range of climatic zones and soil types, were selected in Sweden. They focused on the role of combining ley in crop rotations with the manure application (livestock farm), as opposed to the management without ley and receiving only inorganic fertilizer (arable farm). In ten out of the 12 study sites, livestock farm management tended to have higher proportions of aliphatic and double bonded C groups, as estimated by mid-infrared spectroscopy. This was further confirmed by ¹³C NMR analysis, which found greater proportions of O-alkyl and di-O-alkyl groups and less aromatic C in livestock farm than arable farm management in five of the eight sites analyzed. The changes in SOM composition were reflected in microbial functional profiles across many sites: soils from livestock farm management utilized more carbohydrates and amino acids, while polymer and aromatic compounds were associated with arable farm management. Overall, shifts in both microbial functional profiles and SOM composition showed great consistency across geographical and climatic zones. Livestock farm management maintained higher levels of microbial functional diversity and were associated with higher proportions of “reactive” C functional groups. Our investigation demonstrates that livestock farm management could maintain soil fertility over the long-term via the changes in SOM composition and the regulation of microbial functional profiles.

土壤有机质 (SOM) 在维持土壤肥力和其他生态系统功能方面很重要。然而，集约化农业的土地管理导致 SOM 水平下降，对土壤肥力和质量产生连锁反应。因此，确保 SOM 不枯竭和更好地维持土壤功能的土地管理方案越来越受到关注。然而，关于不同土地管理如何影响 SOM 的组成和相关微生物功能谱的知识有限。在瑞典选择了 12 项长期田间试验，涵盖广泛的气候带和土壤类型。他们专注于将 ley 在轮作中与施肥（牲畜农场）相结合的作用，而不是没有 ley 的管理并且只接受无机肥料（耕地）。根据中红外光谱法估计，在 12 个研究地点中的 10 个中，畜牧场管理往往具有较高比例的脂肪族和双键 C 基团。这进一步证实了¹³C NMR 分析发现，在所分析的八个地点中的五个地点中，与耕地管理相比，畜场中 O-烷基和二-O-烷基的比例更高，芳香族 C 更少。SOM 组成的变化反映在许多地点的微生物功能谱中：来自畜牧场管理的土壤利用了更多的碳水化合物和氨基酸，而聚合物和芳香族化合物与耕地管理有关。总体而言，微生物功能谱和 SOM 组成的变化在地理和气候带之间表现出高度的一致性。畜牧养殖场管理保持较高水平的微生物功能多样性，并与较高比例的“反应性”C 官能团相关。