Nitrogen release and carbon mineralisation from soil organic matter fractions in three cotton crop rotation and natural vegetation soils

Data consists of results from a 14-day incubation experiment measuring nitrogen (N) mobilisation and carbon (C) mineralisation from coarse (≥ 50 μm) and fine (≤ 50 μm) soil organic matter (SOM) fractions, whole soil, and whole soil treated with dispersal and lyophilization as per separated fractions. The aims of this experiment were to determine the contribution of SOM fractions of N mineralisation, to validate measurement of separated SOM fractions against whole soil, and to determine if theorised mechanisms of C stabilisation predict N stability in SOM fractions. \nNitrogen mobilisation was measured as the change in concentration of dissolved organic N (DON), free amino acid-N (FAAN), nitrate (NO3) and ammonium (NH4) concentrations, and carbon mineralisation measured as cumulative carbon dioxide (CO2) evolution. Soils (0-10 cm) from four management systems were included: continuous cotton (CC), cotton-vetch rotation (CV), cotton-wheat rotation (CW) and nearby uncleared vegetation (NV; mixed native and invasive species). The soil is classified as a Grey Vertosol under the Australian Soil Classification (Isbell 2016). The data also includes fraction or soil organic C and total N content measured by Leco combustion, and C content in particulate-, humic- and resistant organic C (POC, HOC and ROC, respectively) fractions measured by Leco and 13C-NMR as per Baldock et al. 2013, Soil Res. ROC is split into ROC-total (ROC_t), ROC-coarse (ROC_c), and ROC-fine (ROC_f). \nFull details of methods and presentation of data can be found in “Opposing patterns of carbon and nitrogen stability in soil organic matter fractions”, European Journal of Soil Science, in press.\nAssociated R code for data processing and statistical analysis can be found here: https://zenodo.org/doi/10.5281/zenodo.11063487 \n

本数据集包含14天培养实验的结果，测定了粗粒（≥50μm）和细粒（≤50μm）土壤有机质（SOM）组分、全土以及按分离组分处理方式进行分散和冻干的全土中的氮素（N）迁移和碳（C）矿化情况。本实验的目的在于明确SOM组分对氮矿化的贡献，验证分离SOM组分的测定结果与全土的一致性，并探究碳稳定的理论机制是否可预测SOM组分中的氮稳定性。
氮素迁移通过溶解性有机氮（DON）、游离氨基酸氮（FAAN）、硝酸盐（NO3）和铵盐（NH4）浓度的变化来测定，碳矿化则通过累积二氧化碳（CO2）释放量来测定。实验包含四种管理系统下的0-10cm土层土壤：连作棉花（CC）、棉花-野豌豆轮作（CV）、棉花-小麦轮作（CW）以及邻近的未开垦植被区（NV；本地与入侵物种混合）。根据澳大利亚土壤分类系统（Isbell 2016），该土壤被归类为灰色变性土。数据还包含通过Leco燃烧法测定的各组分土壤有机碳和全氮含量，以及按照Baldock等人（2013，《土壤研究》）的方法，通过Leco燃烧法和13C核磁共振测定的颗粒态、腐殖质态和难降解有机碳（分别为POC、HOC和ROC）组分中的碳含量。ROC进一步分为总ROC（ROC_t）、粗粒ROC（ROC_c）和细粒ROC（ROC_f）。
方法和数据呈现的完整细节可参见《土壤有机质组分中碳和氮稳定性的相反模式》一文（《欧洲土壤科学杂志》，待发表）。
数据处理和统计分析的相关R代码可在此获取：https://zenodo.org/doi/10.5281/zenodo.11063487