生物炭对向日葵秸秆热解特性及气体产物影响

为了研究生物炭对向日葵秸秆热解的影响,以向日葵秸秆为原料,基于TG-FTIR研究生物炭添加前后向日葵秸秆热解特性与气体产物的变化。结果表明,与向日葵秸秆相比,混合样品主热解区间由276~349℃变得更长,并且发生不同程度的偏移,热解活化能不同程度降低,由60.21降到38.07~50.35 kJ/mol,呋喃类、酸类、含羰基类化合物、芳香醛类、CO、CH4等产物吸光度值存在差异。随着添加500℃制备生物炭比例增加,混合样品热解的活化能减小,释放气体产物中芳香醛类释放量增量减少,CO与CH4释放量降低。添加不同制备温度的生物炭,混合样品热解产生呋喃类、酸类、含羰基类化合物释放量均有所降低;添加500和700℃制备的生物炭,混合样品热解气体产物中芳香醛类增加。添加900℃制备的生物炭,向日葵秸秆热解气体产物中CO产量增加。该研究为向日葵秸秆的有效利用提供理论基础和技术支撑。     

微生物和生物炭联用对猪粪堆肥后重金属Pb和Cd的钝化效果

为探讨微生物和生物炭联用对畜禽粪便堆肥过程中重金属钝化效果的影响,该文研究生物炭(花生壳炭、木屑炭、玉米秸秆炭)与复合微生物菌剂联用对重金属Pb、Cd形态转化及钝化效果的影响。试验结果表明:9个处理高温期维持天数均达无害化卫生要求,生物炭添加比例对堆肥过程中温度变化影响显著。对Pb的钝化效果最优处理是24%花生壳生物炭和1%的菌剂(T9),可交换态分配率较堆前下降16.32%,钝化效率为74.60%。对Cd的钝化效果最优的处理是24%木屑炭和1.5%的菌剂(T3),交换态Cd与堆前相比下降7.96%,钝化效率为58.13%。统计分析结果表明,重金属Pb、Cd的钝化效果与堆肥过程中平均pH值呈显著正相关,重金属Pb的钝化效果与堆肥过程中温度平均值呈显著正相关,重金属Cd的钝化效果与有机质降解率呈显著正相关。     

A preliminary trial of the sedation induced by intranasal administration of midazolam alone or in combination with dexmedetomidine and reversal by atipamezole for a short‐term immobilization in pigeons

ObjectiveTo assess the sedative and immobilization effect of intranasal administration (INS) of midazolam (MID) without or with INS dexmedetomidine (DXM), and some physiological changes induced by the drugs. The ability of INS atipamezole to reverse the DXM component was also assessed.Study designProspective ‘blinded’ experimental study.AnimalsIn total, 15 pigeons.MethodsPigeons were sedated by INS MID alone at a dose of 5 mg kg⁻¹ (group MID, n = 6) or in combination with INS DXM at a dose 80 μg kg⁻¹ (group MID-DXM, n = 6). Measurements were made of heart rate (HR), respiratory rate (f_R) and cloacal temperature (CT). The degree of sedation was assessed at 15 minutes prior to, immediately after, and at intervals until 100 minutes after drug administrations. Following MID-DXM, INS atipamezole (250 μg kg⁻¹) was administered and the same indices measured 5 and 10 minutes later.ResultsMID had no effect on HR and f_R, and although CT decreased, it remained within physiological range. MID-DXM caused significant falls in HR, f_R and CT that persisted until the end of sedation. Atipamezole antagonized sedation and cardiorespiratory side effects of MID-DXM within 10 minutes of application. In addition, for MID compared to MID-DXM, the lowest sedation scores [10 (7–14) and 10.5 (5–14) versus 2 (1–4) and 2 (1–5)] were achieved in the 10th and 20th minute versus the 20th and 30th minute of the sedation, respectively.Conclusions and clinical relevanceMID alone, given INS had minimal side effects on vital functions but caused inadequate immobilization of pigeons for restraint in dorsal recumbency. MID-DXM caused an effective degree of immobilization from 20 to 30 minutes after administration, at which time birds tolerated postural changes without resistance. Atipamezole antagonized both side effects and sedation, but complete recovery had not occurred within 10 minutes after its application.     

Accelerated induction of etorphine immobilization in blue wildebeest (Connochaetes taurinus) through the addition of hyaluronidase

ObjectiveTo study the effects of the addition of hyaluronidase (HA) to an etorphine/azaperone drug combination on induction times of immobilization.Study designExperimental part-randomized ‘blinded’ cross-over study.AnimalsEight wild managed blue wildebeest (Connochaetes taurinus).MethodsAnimals were immobilized, on separate occasions separated by two weeks, with one of four treatments. Treatments were; ‘Control drugs (CD), etorphine 0.01 mg kg⁻¹ + azaperone at 0.1 mg kg⁻¹; treatment 1 CD + 5000IU HA; treatment 2 CD + 7500 IU HA; and treatment 3 etorphine 0.007 mg kg⁻¹ + azaperone at 0.07 mg kg⁻¹ + 7500 IU HA. Times to first effect and to immobilization (from darting to possible to approach and blindfold) were measured. anova was used to compare treatments. Results are given in means ± SD (range).ResultsFor control, and treatments 1–3 respectively, times (in minutes) to first effect were 1.58 ± 0.42 (1.02–2.10), 1.64 ± 0.42 (0.95–2.17), 1.12 ± 0.24 (0.80–1.48) and 1.60 ± 0.21 (1.13–1.88) and to immobilization were 5.38 ± 1.53 (3.82–8.07), 3.80 ± 1.14 (2.02–5.50), 3.51 ± 1.08 (2.28–5.52) and 4.46 ± 0.67 (3.30–5.40). Compared to control, time to first effect for treatment 2 was significantly shorter. Time to immobilization was significantly quicker in all three treatments containing HA than that for control.Conclusion and clinical relevanceHyaluronidase can reduce the time to immobilization when used in the immobilizing dart, and might be usefully incorporated into etorphine combinations for darting wildlife.     

Soil Carbon Dynamics Under Changing Climate——A Research Transition from Absolute to Relative Roles of Inorganic Nitrogen Pools and Associated Microbial Processes: A Review

It is globally accepted that soil carbon (C) dynamics are at the core of interlinked environmental problems,deteriorating soil quality and changing climate.Its management remains a complex enigma for the scientific community due to its intricate relationship with soil nitrogen (N) availability and moisture-temperature interactions.This article reviews the management aspects of soil C dynamics in light of recent advances,particularly in relation to the availability of inorganic N pools and associated microbial processes under changing climate.Globally,drastic alterations in soil C dynamics under changing land use and management practices have been primarily attributed to the variation in soil N availability,resulting in a higher decomposition rate and a considerable decline in soil organic C (SOC) levels due to increased soil CO2 emissions,degraded soil quality,and increased atmospheric CO2 concentrations,leading to climate warming.Predicted climate warming is proposed to enhance SOC decomposition,which may further increase soil N availability,leading to higher soil CO2 efflux.However,a literature survey revealed that soil may also act as a potential C sink,if we could manage soil inorganic N pools and link microbial processes properly.Studies also indicated that the relative,rather than the absolute,availability of inorganic N pools might be of key importance under changing climate,as these N pools are variably affected by moisture-temperature interactions,and they have variable impacts on SOC turnover.Therefore,multi-factorial studies are required to understand how the relative availability of inorganic N pools and associated microbial processes may determine SOC dynamics for improved soil C management.     

Evaluation of chitosan and alginate immobilized Methylobacterium oryzae CBMB20 on tomato plant growth

Methylobacterium oryzae CBMB20, a promising plant growth promoting bacteria (PGPB) and a biocontrol agent, was immobilized in different formulations such as wet chitosan, dry chitosan, wet alginate and dry alginate and were tested for tomato plant growth promotion. Chitosan solution (1.5%) with pH 5.5–6.0 and 90 min contact time was found optimal for immobilization. The chitosan formulations showed better entrapment efficiency and good degradability resistance apart from slow release of cells under prolonged incubation. Survivability of bacteria (80%) was observed in wet chitosan formulation even after 90 days of storage at 4°C. The spermosphere survival of bacteria was high in both dry and wet chitosan formulations applied soils even after 21 days under greenhouse conditions. While the alginate formulation degraded fully, partial degradation of chitosan formulation was observed even after 30 days, indicating its ability to support the survival of M. oryzae CBMB20 in soil. Plants inoculated with wet chitosan formulation registered 1.3 fold increase in the shoot and root length and dry weight compared to other treatments. Hence, chitosan formulation supporting better plant growth compared to alginate will be a better carrier for taking bacteria to the plant rhizosphere and thereby promote plant growth.     

不同钝化剂对铅锌矿区周边农田镉铅污染钝化修复研究

采用大田试验和盆栽试验,研究了海泡石(S)、石灰(L)、腐植酸(H)、生物炭(B)和钙镁磷肥(P)对云南某铅锌矿区周边玉米农田的修复效果,并采用BCR形态分级试验研究土壤钝化前后重金属形态的变化。结果表明:石灰和海泡石可显著提高土壤pH。钝化处理可显著降低DTPA提取态Cd、Pb含量,盆栽试验中,生物炭45 t·hm~(-2)处理对Cd钝化效率可达45.3%,石灰2.25 t·hm~(-2)处理对Pb钝化效率可达60.6%;大田试验中,钙镁磷肥3 t·hm~(-2)处理对Cd最高钝化效率可达48.3%,石灰4.5 t·hm~(-2)处理对Pb钝化效率可达25.3%。石灰、海泡石和生物炭对重金属形态变化影响显著,可促进重金属由高活性形态向低活性形态转换。钝化处理可显著降低玉米籽粒中Cd、Pb含量,生物炭22.5 t·hm~(-2)处理下,Cd最大降幅85%,作物达到食品安全国家标准(GB 2762—2012,Cd≤0.1 mg·kg-1),石灰4.5 t·hm~(-2)处理下,Pb最大降幅59.6%,但未达到食品安全国家标准(GB 2762—2012,Pb≤0.2 mg·kg-1)。部分钝化剂可以起到增产的作用,腐植酸22.5 t·hm~(-2)处理下可增产29.1%。综合分析不同钝化剂及其施用量的效果可知,海泡石和石灰是对该矿区周边Cd、Pb污染农田修复效果最佳的钝化剂,最佳施用量分别为海泡石45 t·hm~(-2)和石灰2.25 t·hm~(-2)。     

土壤重金属钝化效果评估——基于大田试验的研究

采用野外大田试验,研究了钙镁磷肥(Calcium-magnesia phosphate fertilizer)、麦饭石(Medical stone)、氧化铁吸附剂(Ferric oxide adsorbent)、氧化铝复合材料(Alumina composite)、植物型有机肥(Plant-based organic fertilizer)、牛粪(Cow dung)、骨炭(Bone char)对某地重金属污染农田的钝化修复效果,并利用动态加权评估方法评估了这几种钝化材料的综合适用性。试验结果表明:几种材料对土壤pH影响均较小,钙镁磷肥、麦饭石微量提高了土壤pH,与对照组相比分别增加0.68和0.74个单位;施加植物型有机肥、牛粪和骨炭提高了土壤有机质含量,与对照组相比分别增加了3.19、2.64 g·kg~(-1)和1.17 g·kg~(-1)(10.04%、8.31%和3.68%)。几种材料在0.6%的投加量下,除植物型有机肥外均有较好钝化效果,土壤有效态镉降低18%以上,且显著减少糙米中镉蓄积量(0.062～0.087mg·kg~(-1)),低于国家食品安全标准限值。为综合评估几种材料的效果及适用性,以土壤重金属有效态含量、糙米镉含量、修复成本和产量为指标构建动态加权函数综合评估模型,评估结果表明,钙镁磷肥的综合修复效果最好,其次为骨炭和植物型有机肥。     

一株海洋石油降解菌的特性分析及固定化研究

从辽东湾沿岸受石油污染的沉积物中筛选得到一株石油降解菌株BHB-16,对该菌进行了形态以及16SrDNA系统发育分析,初步确定该菌株为Lutibacterium菌属。应用沸石和珊瑚石作为载体进行该菌株的固定化研究,确定当沸石作为载体时,固定化的最佳条件为:菌株接种量为0.6mL,培养时间28h,载体投加量为10mL;选用珊瑚石为载体时,固定化的最佳条件为:菌株接种量为0.6mL,培养时间29h,载体投加量为12mL;此外,用沸石和珊瑚石固定后的菌株,其对于柴油的降解率相对于游离菌分别提高了14.4%和29.6%,初步选用珊瑚石作为载体进行菌株的固定化使其具有更好的石油降解能力。