ChronoseqITS

The soil fungal community was surveyed across a 52-year chronosequence of soil recultivation after open-mining, during two seasons (March-winter, July-summer). The study sites correspond to agricultural fields located within an area of 25 km 2 (6°15’0’ E to 6°21’0’ E and 50°50’5’ N to 50°53’0’ N) of an open-cast lignite mine between Cologne, Aachen, Mönchengladbach, and Düsseldorf. The soil extraction, deposition and recultivation process leads to a chronosequence of fields recultivated from less than one year to fields recultivated for 52 years. During the first three years, fields are permanently covered by alfalfa and never receive artificial fertilisers or biocide treatments (fields recultivated since 2016, 2015, 2014 and 2013, referred to as phase 1). In the following two years, agricultural practises are resumed with barley cropping by RWE Power AG, and a N:P:K (1:0.4:0.6) fertilisation of 437 kg ha−1 a−1 (fields recultivated since 2012 and 2011 referred to as phase 2). Afterwards, fields are returned to farmers and conventionally managed with a crop sequence of winter wheat after sugar beet, one tillage a year to 30 cm depth, and a continuous management practice following area-typical agricultural practice and plant-protection guidelines (fields recultivated since 2006, 1990, 1979, 1971 and 1964, referred to as phase 3). Other agricultural fields that have not yet been subject to extraction were sampled too (referred to as pre-mining phase). The soil fungal community was analyzed with 300 bp paired-end Illumina MiSeq sequencing of ITS2 sequences (primers fITS7: 5′‐GTGARTCATCGAATCTTTG‐3′ / ITS4: 5′‐TCCTCCGCTTATTGATATGC‐3′). ESVs were inferred using DADA2 in R. Taxonomic annotations were performed using the Naive Bayesian Classifier against UNITE (version of 10.05.2021). Raw sequencing reads are available at ENA under study project PRJEB51095. Fungal ESV sequences are available at ENA under accession numbers OV986018-OV989728. The analysed dataset including the OTU count table, OTU taxonomy, and sample metadata is available as a phyloseq object stored in a single .RDS R (in the software R, use readRDS() function). The publication can be found at https://doi.org/10.1007/s00248-022-02058-w.本研究针对露天采矿后复垦时长跨度达52年的土壤时间序列开展了土壤真菌群落调查，采样覆盖两个季节（3月代表冬季，7月代表夏季）。 研究样地均为农田，位于科隆、亚琛、门兴格拉德巴赫与杜塞尔多夫之间的露天褐煤矿区25 km²范围内，地理坐标为东经6°15′0″至6°21′0″、北纬50°50′5″至50°53′0″。 土壤采掘、堆积与复垦流程形成了复垦年限从不足1年至52年的样地时间序列。 复垦前三年的样地永久种植紫花苜蓿，且不施加人工肥料或杀生物剂处理，2016、2015、2014及2013年复垦的样地归为阶段1。 随后两年恢复农业耕作，由RWE Power AG种植大麦，并按437 kg ha⁻¹ a⁻¹的用量施加N:P:K（1:0.4:0.6）型复合肥，2012、2011年复垦的样地归为阶段2。 此后样地交还农户，采用常规农业管理模式：前作为甜菜，后茬种植冬小麦，每年进行一次深度为30 cm的耕作，并遵循区域典型农业操作规范与植物保护指南开展持续管理，2006、1990、1979、1971及1964年复垦的样地归为阶段3。 本研究同时对尚未进行采掘的农田开展了采样，该类样地归为采前阶段。 土壤真菌群落通过ITS2序列的300 bp双端Illumina MiSeq测序进行分析，所用引物为fITS7：5′‐GTGARTCATCGAATCTTTG‐3′ 与 ITS4：5′‐TCCTCCGCTTATTGATATGC‐3′。 采用R语言中的DADA2工具推断扩增序列变体（Exact Sequence Variants, ESVs）；分类注释基于UNITE数据库（2021年5月10日版本），使用朴素贝叶斯分类器完成。 原始测序数据已上传至欧洲核苷酸档案馆（European Nucleotide Archive, ENA），研究项目编号为PRJEB51095；真菌ESV序列的登录号范围为OV986018-OV989728，同样存储于ENA。 本分析所用数据集包含操作分类单元（Operational Taxonomic Unit, OTU）计数表、OTU分类注释信息与样品元数据，以phyloseq对象的形式存储于单个.RDS文件中，可在R软件中通过readRDS()函数读取。 相关研究论文可通过链接https://doi.org/10.1007/s00248-022-02058-w获取。