Nitrogen cycling rates from sagebrush and cheatgrass-invaded soils in the Northern Great Basin (2008)

This dataset contains data supporting the paper: DeCrappeo, N.M., DeLorenze, E.J., Giguere, A.T., Pyke, D.A., and Bottomley, P.J. Fungal and bacterial contributions to nitrogen cycling in cheatgrass-invaded and uninvaded native sagebrush soils of the western USA (accepted at the journal Plant and Soil). The purpose of the study was to evaluate the relative contributions of soil bacteria and fungi to inorganic nitrogen (N) cycling in sagebrush and cheatgrass-invaded soils using a 15N isotope dilution experiment. Soils were collected from sagebrush and cheatgrass rhizospheres at six paired sites in southwest Idaho and southeast Oregon. In order to partition the contribution of each microbial group to N cycling, soils were treated with isotopically labeled N sources and protein synthesis inhibitors. Bronopol and cycloheximide block protein synthesis in bacteria and fungi, respectively; nitrogen can still be taken up by the organisms, but the organisms are unable to assimilate the nutrient into biomass. Laboratory incubations were carried out to study the partitioning of N to microbial biomass and dissolved inorganic nitrogen pools, which were then used to calculate the following nitrogen transformation rates: gross mineralization, net mineralization, ammonium consumption, and net nitrification.本数据集包含支撑以下学术论文的配套数据：DeCrappeo, N.M.、DeLorenze, E.J.、Giguere, A.T.、Pyke, D.A. 与 Bottomley, P.J. 合著的《美国西部雀麦入侵与未入侵原生蒿属灌丛土壤中真菌与细菌对氮循环的贡献》（已被《Plant and Soil》期刊录用）。本研究旨在通过15N同位素稀释实验（15N isotope dilution experiment），评估原生蒿属灌丛土壤与被雀麦入侵的土壤中，土壤细菌与真菌对无机氮（N）循环的相对贡献程度。本研究从爱达荷州西南部与俄勒冈州东南部的6个配对样地中，采集了蒿属灌丛与雀麦根际的土壤样本。为解析各微生物类群对氮循环的贡献，研究人员对土壤施加了同位素标记氮源与蛋白质合成抑制剂。溴硝醇（Bronopol）与放线菌酮（cycloheximide）可分别阻断细菌与真菌的蛋白质合成过程：此时微生物仍可摄取氮素，但无法将该养分同化为自身生物量。通过室内培养实验，研究人员解析了氮在微生物生物量与溶解态无机氮库中的分配情况，并以此计算得到以下氮转化速率：总矿化速率、净矿化速率、铵消耗速率以及净硝化速率。