Datasets produced by Multiscale Impacts of Cyanobacterial Crusts on Landscape Stability (4/6) (NERC Grant NE/K011464/1)

Data from laboratory experiments conducted as part of project NE/K011464/1 (associated with NE/K011626/1) Multiscale Impacts of Cyanobacterial Crusts on Landscape stability. Soils were collected from two sites in eastern Australia and transferred to a laboratory at Griffith University, Queensland for conduct of experiments. Soils were A, a sandy loam, and B a loamy fine sand. Trays 120 mm x 1200 mm x 50 mm were filled with untreated soil that contained a natural population of biota. Soils were either used immediately for experiments (physical soil crust only: PC) or were placed in a greenhouse and spray irrigated until a cyanobacterial crust has grown from the natural biota. Growth was for a period of 5 days (SS), c.30 days (MS2) or c.60 days (MS1). Following the growing period (if applicable) trays were placed in a temperature/humidity controlled room at 35° and 30% humidity until soil moisture (measured 5 mm below the surface) was 5%. Trays were then subject to rainfall simulation. Rainfall intensity of 60 mm hr-1 was used and rainfall was applied for 2 minutes (achieving 2 mm application), 8 minutes (achieving 8 mm application) or 15 minutes (achieving 15 mm application). Following rainfall, trays were returned to the temperature/humidity-controlled room under UV lighting until soil moisture at 5 mm below the surface was 5%. A wind tunnel was then placed on top of each tray in turn and a sequential series of wind velocities (5, 7, 8.5, 10, 12 m s-1) applied each for one minute duration. On each tray the five wind velocities were run without saltation providing a cumulative dust flux. For the highest wind speed, an additional simulation run was conducted with the injection of saltation sands. Three replicates of each rainfall treatment were made. Variables measured include photographs, spectral reflectance, surface roughness, fluorescence, penetrometry, chlorophyll content, extracellular polysaccharide content, Carbon, Nitrogen and splash erosion and particle-size analysis (of wind eroded material). Details of rainfall simulator, growth of cyanobacteria, laser soil surface roughness characterisation and wind tunnel design and deployment in Strong et al., 2016; Bullard et al. 2018, 2019. Bullard, J.E., Ockelford, A., Strong, C.L., Aubault, H. 2018a. Impact of multi-day rainfall events on surface roughness and physical crusting of very fine soils. Geoderma, 313, 181-192. doi: 10.1016/j.geoderma.2017.10.038. Bullard, J.E., Ockelford, A., Strong, C.L., Aubault, H. 2018b. Effects of cyanobacterial soil crusts on surface roughness and splash erosion. Journal of Geophysical Research – Biogeosciences. Doi: 10.1029/2018. Strong, C.S., Leys, J.F., Raupach, M.R., Bullard, J.E., Aubault, H.A., Butler, H.J., McTainsh, G.H. 2016. Development and testing of a micro wind tunnel for on-site wind erosion simulations. Environmental Fluid Mechanics, 16, 1065-1083.本数据集源自项目NE/K011464/1（关联项目NE/K011626/1）"蓝藻结皮(cyanobacterial crusts)对景观稳定性的多尺度影响"相关实验室实验数据。 研究从澳大利亚东部两个采样点采集土壤，转运至昆士兰州格里菲斯大学实验室开展实验。供试土壤分为两类：A组为砂壤土(sandy loam)，B组为壤质细砂土(loamy fine sand)。 实验采用尺寸为120 mm × 1200 mm × 50 mm的托盘，装填含天然土壤生物群落的未处理土壤。土壤分为两组处理模式：一组即刻用于实验（仅物理结皮组，PC）；另一组置于温室中喷雾灌溉，待天然土壤生物群落形成蓝藻结皮，培养时长分别为5天（SS组）、约30天（MS2组）和约60天（MS1组）。 培养结束后（适用组），将托盘移入温湿度可控室，设置温度35℃、相对湿度30%，直至表层下5 mm处的土壤含水率降至5%。随后开展降雨模拟实验：采用60 mm·h⁻¹的降雨强度，分别施加降雨时长2 min（累计降雨量2 mm）、8 min（累计降雨量8 mm）和15 min（累计降雨量15 mm）。 降雨实验结束后，将托盘放回温湿度可控室并辅以紫外光照，直至表层下5 mm处的土壤含水率再次降至5%。 随后依次将风洞(wind tunnel)置于每个托盘上方，施加一系列连续风速（5、7、8.5、10、12 m·s⁻¹），每档风速持续1 min；所有风速实验均在无风沙盐跃(saltation)的条件下开展，累计收集粉尘通量。针对最高风速档位，额外开展一次注入盐跃沙的模拟实验。 每个降雨处理设置3次重复实验。 本次实验测定的指标包括：图像采集、光谱反射率、表面粗糙度、荧光特性、贯入阻力测定、叶绿素含量、胞外多糖(extracellular polysaccharide)含量、碳/氮含量、溅蚀(splash erosion)量及风蚀颗粒物粒径分析。 降雨模拟器搭建、蓝藻结皮培养方法、激光土壤表面粗糙度表征技术，以及风洞的设计与部署详见Strong等（2016）、Bullard等（2018、2019），具体文献信息如下： 1. Bullard, J.E., Ockelford, A., Strong, C.L., Aubault, H. 2018a. 多日降雨事件对极细土壤表面粗糙度与物理结皮的影响. 《Geoderma》, 313, 181-192. doi: 10.1016/j.geoderma.2017.10.038. 2. Bullard, J.E., Ockelford, A., Strong, C.L., Aubault, H. 2018b. 蓝藻土壤结皮对表面粗糙度与溅蚀的影响. 《Journal of Geophysical Research – Biogeosciences》, 待刊. Doi: 10.1029/2018. 3. Strong, C.S., Leys, J.F., Raupach, M.R., Bullard, J.E., Aubault, H.A., Butler, H.J., McTainsh, G.H. 2016. 用于原位风蚀模拟的微型风洞的研制与测试. 《Environmental Fluid Mechanics》, 16, 1065-1083.