Given the increasingly recognised importance of microbial biomass (MB) in soil organic carbon (SOC) sequestration, knowledge of the microbial ionome beyond carbon (C), nitrogen (N) and phosphorus (P) becomes crucial. The microbial ionome could indicate nutritional restrictions related to MB growth and microbial necromass C (MN-C) accumulation. In this study, soils receiving different combinations of mineral N, P and potassium (K) were sampled in the Askov long-term field experiment, Denmark, and analysed for MB elemental composition including N, P, K, magnesium (Mg), manganese (Mn) and zinc (Zn) using fumigation-extraction and ICP-OES. Furthermore, bacterial, archaeal and fungal gene abundance was determined by PCR as microbial community shifts may relate to microbial ionome shifts. MN-C was determined by amino sugar analysis. MB-C was unaffected by fertiliser treatments and not correlated with MN-C. N fertilisation increased MN-C. N and K additions increased plant-derived SOC, indicating the importance of N for microbial and plant-derived SOC accumulation. Availability of P and K increased MB-P and MB-K, respectively, and reduced the MB-C:P ratio but not MB-C:K. N fertilisation reduced the pH and increased Mn availability which increased MB-Mn and reduced MB-C:Mn. ITS1 gene copies responded positively to P availability. A reduced MB-C:Mn ratio was associated with a relative increase in fungal gene copy abundance. This was linked to an increase in SOC, indicating a positive link between Mn availability, fungal abundance and SOC level, yet this was not reflected in MN-C accumulation, but by the accumulation of plant-derived SOC, possibly due to reduced plant C turnover.

中文翻译：

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通过阿斯科夫长期田间试验阐明矿肥 N、P 和 K 对土壤中微生物生物量、坏死物和离子组的影响


鉴于人们日益认识到微生物生物量 (MB) 在土壤有机碳 (SOC) 封存中的重要性，了解碳 (C)、氮 (N) 和磷 (P) 之外的微生物离子组变得至关重要。微生物离子组可以表明与 MB 生长和微生物坏死物 C (MN-C) 积累相关的营养限制。在这项研究中，在丹麦阿斯科夫长期田间试验中对接受不同矿物质 N、P 和钾 (K) 组合的土壤进行了采样，并分析了 MB 元素组成，包括 N、P、K、镁 (Mg)、锰(Mn) 和锌 (Zn)，采用熏蒸萃取和 ICP-OES。此外，通过 PCR 测定细菌、古菌和真菌基因丰度，因为微生物群落变化可能与微生物离子组变化有关。 MN-C通过氨基糖分析测定。 MB-C 不受肥料处理的影响，并且与 MN-C 不相关。施氮肥增加了 MN-C。氮和钾的添加增加了植物来源的 SOC，表明氮对于微生物和植物来源的 SOC 积累的重要性。 P和K的可用性分别增加了MB-P和MB-K，并降低了MB-C:P比率，但不降低MB-C:K。施氮肥降低了 pH 值并增加了锰的利用率，从而增加了 MB-Mn 并减少了 MB-C:Mn。 ITS1 基因拷贝对磷的可用性有积极的反应。 MB-C:Mn 比率降低与真菌基因拷贝丰度的相对增加相关。这与 SOC 的增加有关，表明锰的有效性、真菌丰度和 SOC 水平之间存在正相关关系，但这并未反映在 MN-C 积累中，而是反映在植物来源的 SOC 积累中，可能是由于植物 C 减少所致周转。