Sources and turnover of soil organic matter in Pfynwald irrigation experiment

This dataset contains all data on which the following publication below is based.
Paper Citation:
Guidi, C., Lehmann, M.M., Meusburger, K., Saurer, M., Vitali, V., Peter, M., Brunner, I., Hagedorn, F. (accepted). Tracing sources and turnover of soil organic matter in a long-term irrigated dry forest using a novel hydrogen isotope approach. Soil Biology and Biochemistry.
Please cite this paper together with the citation for the datafile.
Data from a 17-year-long irrigation experiment (Pfynwald, Switzerland) in a naturally dry forest dominated by 100-year-old pine trees (Pinus sylvestris).
Data include: (1) Isotopic composition (stable isotope ratios of non-exchangeable hydrogen δ2Hn, carbon δ13C, and nitrogen δ15N) and Hn, C and N concentrations in SOM sources (fresh Pinus sylvestris needles, litter layer, fine roots), bulk SOM (organic layer, 0-2 cm, 2-5 cm, 60-80 cm), particle-size fractions (depths: 0-2 cm, 2-5 cm; cPOM: coarse POM; fPOM: fine POM; MOM: mineral-associated organic matter); (2) Mass loss, δ2Hn values and Hn concentrations of Pinus sylvestris fine roots and needle litter (litter decomposition experiments from Herzog et al. 2019, ISME journal, and Guidi et al. 2022, Global Change Biology); (3) Relative source contribution (foliar litter, fine roots, and mycelia) to bulk SOM and fractions estimated using Bayesian mixing models (R package MixSIAR, version 3.1.12) with irrigation and depth as fixed factors. The models were informed with δ13C, δ15N and δ2Hn values and C, N, and Hn concentrations of foliar litter, roots, and mycelia as input sources. Given the kinetic isotope fractionation occurring during microbial SOM decomposition, the mixing models were informed with isotope fractionation factors, representing the isotope enrichment from sources to soils; (4) Fraction of new organic Hn (Fnew) over the irrigation period, calculated using a simple end-member mixing model according to Balesdent et al. (1987) and mean residence time estimated as MRT = - t / ln (1 - Fnew), with t time in years since irrigation started and assuming single-pool model with first-order kinetics.

本数据集包含支撑下述已发表论文的全部相关数据。
论文引用信息：
Guidi, C.、Lehmann, M.M.、Meusburger, K.、Saurer, M.、Vitali, V.、Peter, M.、Brunner, I.、Hagedorn, F.（已录用）. 利用新型氢同位素示踪法探究长期灌溉干旱林土壤有机质的来源与周转. 《土壤生物学与生物化学》（Soil Biology and Biochemistry）.
请在引用该数据文件的同时一并引用此论文。
数据源自瑞士菲恩瓦尔德（Pfynwald）一项为期17年的灌溉实验，实验场地为以百年生欧洲赤松（Pinus sylvestris）为优势种的天然干旱林。
数据包含以下内容：
(1) 土壤有机质（Soil Organic Matter, SOM）源组分（新鲜欧洲赤松针叶、枯落物层、细根）、整体土壤有机质（有机层、0-2 cm、2-5 cm、60-80 cm土层）、粒级组分（土层深度：0-2 cm、2-5 cm；cPOM：粗颗粒有机质（coarse POM）、fPOM：细颗粒有机质（fine POM）、MOM：矿质结合态有机质（mineral-associated organic matter））中的同位素组成（不可交换氢的稳定同位素比值δ²Hn、碳δ¹³C及氮δ¹⁵N），以及Hn、C、N元素含量；
(2) 欧洲赤松细根和针叶枯落物的质量损失率、δ²Hn值及Hn浓度（数据来自Herzog等人2019年发表于《ISME Journal》的研究，以及Guidi等人2022年发表于《Global Change Biology》的枯落物分解实验）；
(3) 以灌溉处理和土层深度为固定因子，利用贝叶斯混合模型（R包MixSIAR，版本3.1.12）估算得到的整体土壤有机质及各组分的相对源贡献（叶枯落物、细根及菌丝）。模型输入参数包括叶枯落物、根系与菌丝的δ¹³C、δ¹⁵N、δ²Hn比值及C、N、Hn含量；考虑到微生物降解土壤有机质过程中存在动力学同位素分馏，模型同时引入了代表从源物质到土壤的同位素富集效应的同位素分馏因子；
(4) 灌溉周期内新增有机Hn占比（Fnew），该指标依据Balesdent等人1987年提出的简单端元混合模型计算得到；同时依据公式MRT = -t / ln(1 - Fnew)估算平均驻留时间（mean residence time, MRT），其中t为灌溉开始后的时长（以年为单位），并假设采用一级动力学的单库模型。