Analysis of spatial microbial properties from experimental plots of the Jena experiment (September 2010)@en

The study was carried out on the main plots (Main Experiment) of a large grassland biodiversity experiment, the Jena Experiment. In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. This data set consists of standard deviation (SD), mean and stability (stab) of soil microbial basal respiration (µl O2/h/g dry soil) and microbial biomass carbon (µg C/g dry soil). Data were derived by taking soil samples and measuring basal and substrate-induced microbial respiration with an oxygen-consumption apparatus. Samples for calculating the spatial stability of soil microbial properties were taken on the 20th of September in 2010. Oxygen consumption of soil microorganisms in fresh soil equivalent to 3.5 g dry weight was measured at 22°C over a period of 24 h. Basal respiration (µlO2/g dry soil/h) was calculated as mean of the oxygen consumption rates of hours 14 to 24 after the start of measurements. Substrate- induced respiration was determined by adding D-glucose to saturate catabolic enzymes of microorganisms according to preliminary studies (4 mg g-1 dry soil solved in 400 µl deionized water). Maximum initial respiratory response (µl O2/g dry soil/ h) was calculated as mean of the lowest three oxygen consumption values within the first 10 h after glucose addition. Microbial biomass carbon (µg C/g dry soil) was calculated as 38 × Maximum initial respiratory response according to prelimiray studies.本研究依托大型草原生物多样性实验——耶拿实验（Jena Experiment）的主样地（主实验）开展。该主实验从涵盖4个功能群（禾草类、豆科类、高大草本与矮小草本）的60个物种种库中，设置了82块20×20米的草原样地。2002年5月，研究人员向样地中播种来自该物种库的不同数量的植物物种，以此构建植物物种丰富度（1、2、4、8、16和60种）与功能群丰富度（1、2、3、4个功能群）的梯度系列。样地通过每年两次除草与刈割进行管护。本数据集包含土壤微生物基础呼吸（soil microbial basal respiration，µl O₂/h/g干土）与微生物生物量碳（microbial biomass carbon，µg C/g干土）的标准差（SD）、均值及稳定性（stab）。数据通过采集土壤样品，利用耗氧装置测定微生物基础呼吸与底物诱导呼吸（substrate-induced respiration）获得。用于计算土壤微生物特性空间稳定性的样品于2010年9月20日采集。称取相当于3.5g干重的新鲜土壤样品，在22℃条件下培养24小时，测定其土壤微生物的耗氧量。基础呼吸以测定开始后14至24小时的耗氧速率均值计算得到，单位为µlO₂/g干土/h。底物诱导呼吸的测定参照预实验方法，通过添加D-葡萄糖以饱和微生物的分解代谢酶：将4mg·g⁻¹干土的D-葡萄糖溶于400µl去离子水中后添加。最大初始呼吸响应（maximum initial respiratory response，µl O₂/g干土/h）以葡萄糖添加后前10小时内最低的3个耗氧数值的均值计算得到。根据预实验结果，微生物生物量碳（µg C/g干土）按38×最大初始呼吸响应进行换算。