不同植被类型对土壤微生物量碳氮及土壤呼吸的影响

对四种植被类型下土壤微生物量碳、氮、土壤呼吸速率以及代谢熵的研究,结果表明,土壤微生物量碳、氮以及土壤呼吸在四种植被类型间差异显著,而土壤微生物代谢熵之间差异不明显。且不同植被演替阶段土壤微生物量碳、氮从初级阶段到次生林阶段逐步增大,从次生林到成熟林阶段明显减小;土壤呼吸随着植被的正向演替,呼吸速率逐渐增强;四种植被类型间土壤微生物代谢熵在次生林中最低,为0.44mgg-1h-1,万熟林地中最高,为1.01mgg-1h-1,表明土壤微生物对土壤碳的利用效率次生林较高,成熟林地较低。     

川西平原土壤微生物生物量碳氮磷含量特征及其影响因素分析

本文通过区域调查采样和统计分析,探讨了川西平原土壤微生物生物量碳（MBC）、土壤微生物生物量氮（MBN）和土壤微生物生物量磷（MBP）含量特征及其对气候、海拔、母质和土地利用等因素的响应,揭示了其关键影响因素,以期为川西平原地区土壤质量管理提供参考。结果表明,不同土壤类型的MBC、MBN和MBP含量表现为冲积土显著高于水稻土、潮土和黄壤（P<0.05）,潮土MBC/MBN显著高于水稻土。气候和海拔的影响为：MBC、MBN和MBP含量随着≥ 0℃积温、≥ 10℃积温、年均温和年均降水量的增加呈指数减少,而随干燥度和海拔增加呈线性增加。不同成土母质中,MBC、MBN和MBP含量均为灰色冲积物显著高于老冲积物。不同土地利用方式下,三者含量为草地显著高于水田和旱地,水田、旱地和林地差异不显著。皮尔森相关分析和冗余分析表明,MBC和MBN均与≥ 0℃积温、年均温呈极显著负相关（P<0.01）,与海拔呈极显著正相关关系,MBP与母质呈现极显著负相关关系。逐步回归分析表明,MBC主要受年均温、干燥度、年均降水量和母质的影响;MBN主要受海拔、干燥度和年均降水量的综合影响;MBP主要受母质、年均温、≥ 10℃积温和年均降水量的调控。因此,川西平原土壤MBC、MBN、MBP能灵敏地反映不同采样点气候的变化,可为该区气候变化下土壤碳、氮、磷的响应预测提供参考。     

不同农田生态系统土壤微生物生物量碳的变化研究

试验研究不同农田生态系统土壤微生物生物量碳的变化结果表明,长期单施N、P肥处理对土壤有机碳和微生物生物量碳的影响不明显,施有机肥处理土壤微生物生物量碳及微生物生物量碳/有机碳值均高于其他施肥处理,轮作中引入豆科作物或豆科连作均对土壤微生物生物量碳的积累有显著作用。     

不同措施对滨海盐渍土壤呼吸、电导率和有机碳的影响

在苏北滩涂围垦区的轻度和中度盐渍土上,通过田间试验,研究了不同农田管理措施(传统耕作、施用有机肥、氮肥增施、秸秆还田和免耕)对土壤盐分、呼吸和有机碳等的影响。结果表明,0~40cm土层平均电导率在玉米种植季明显升高,小麦种植季出现小幅降低,轻度盐渍土的电导率为4.57~8.20 d S m~(~(-1)) ,中度盐渍土为4.89~10.13 d S m~(~(-1)) ,处理之间秸秆还田最低,免耕最高,秸秆还田和施用有机肥有效减少了土壤盐分含量。与中度盐渍土相比,轻度盐渍土的呼吸强度较高,在夏玉米和冬小麦种植季节分别高约16%和18%。有机肥、氮肥增施、秸秆还田处理的土壤呼吸均高于对照,而免耕较低。两组试验的土壤有机碳和微生物生物量碳均有缓慢增加,其中施用有机肥和秸秆还田可以大幅提高其含量。轻度盐渍土壤代谢熵高于中度盐渍土,总体上对照最高,免耕最低。     

城市不同功能区绿地土壤理化性质及微生物生物量的分布特征

为提高城市绿地生态系统服务功能和促进城市可持续发展,本文研究了南京市不同功能区绿地表层土壤理化性质和微生物生物量的分布特征。结果显示:土壤p H整体呈碱性且容重偏大;公园绿地土壤全氮、有效磷和速效钾含量显著高于道路绿地;不同功能区绿地土壤有机质含量无显著差异,但公园绿地土壤微生物生物量碳含量和微生物熵显著高于居住区和道路绿地;公园绿地土壤结构和养分均优于道路绿地。土壤微生物生物量碳含量与有机质、全氮和速效钾含量呈极显著正相关,与有效磷含量呈显著正相关,与容重呈极显著负相关;土壤有机质与全氮和速效钾含量呈极显著正相关,与有效磷含量和pH无显著相关性,与容重呈显著负相关。因此,勤松土,合理施肥,增加枯枝落叶等凋落物覆盖,提高土壤养护管理水平对修复城市土壤生态和建设生态城市具有重要意义。     

紫色土丘陵坡地植被恢复过程中土壤微生物生物量碳、微生物熵的变化

采用空间序列代替时间序列的方法,对河南省衡阳市紫色土丘陵坡地植被恢复过程中的土壤微生物生物量碳(SMBC)、微生物熵(qSMBC)的变化特征进行了研究。结果表明:(1)随着植被恢复的进行,SMBC和qSMBC均显著增加;(2)随着土层深度的增加,SMBC显著减小,而qSMBC显著增加;(3)草本群落阶段(Ⅱ)→灌木群落阶段(Ⅲ)→乔木群落阶段(Ⅳ),根际和非根际的SMBC显著增加,表现出根际非根际的特点,阶段Ⅱ的根际与非根际SMBC比值明显高于Ⅲ与Ⅳ。根际和非根际的qSMBC均显著增加,表现出根际非根际的特点,根际和非根际的qSMBC比值差异不显著;(4)相关分析表明,SMBC与qSMBC均与土壤有机碳、阳离子交换量呈极显著或显著正相关关系,与土壤容重呈显著负相关关系。     

高碳基肥对烤烟生长及土壤微生物碳代谢多样性特征的影响

为探究施用高碳基肥对植烟土壤微生物群落功能多样性的影响,采用田间试验研究了不同高碳基肥施用量(0、0.9、1.5和1.8 t/hm~2)处理对烟株生长发育、土壤理化性质和烤后烟叶品质的影响,并利用Biolog-ECO方法分析了土壤微生物碳代谢多样性特征。结果表明:(1)0.9～1.5 t/hm~2高碳基肥显著促进了烤烟株高、茎围、最大叶面积和根系干重等指标,1.8 t/hm~2施用量促进效果明显降低;(2)与对照相比,施用高碳基肥能够降低土壤含水率、提高土壤pH值和微生物量碳氮比;(3)Biologe-ECO分析表明,土壤微生物平均颜色变化率和多样性指数均以施用高碳基肥1.5 t/hm~2处理最高,同时土壤微生物对氨基酸类、聚合物类、碳水化合物类和羧酸类碳源利用率亦有显著提高。主成分分析表明,施用高碳基肥显著改变了土壤微生物功能群落结构,且以1.5 t/hm~2高碳基肥处理下微生物碳代谢多样性得分最高;(4)施用高碳基肥能够改善烤后烟叶化学品质,以1.5 t/hm~2处理效果最佳,总糖、还原糖和钾含量分别较对照显著提高22.81%、35.72%、25.61%。综合来看,许昌烟区高碳基肥的最适宜施用量为1.5 t/hm~2。     

蚯蚓粪对豇豆土壤活性有机碳及微生物活性的影响

为探讨施用蚯蚓粪对豇豆土壤活性有机碳与微生物活性的作用效果,通过大田试验,研究CK(对照,不施肥)、CF(单施化肥)、VC(蚯蚓粪)和VC+CF(蚯蚓粪和化肥各提供50%的氮)等处理对豇豆土壤活性有机碳、碳库管理指数(CPMI)、微生物量碳氮及微生物呼吸、代谢熵的影响。结果表明,与CF相比,施用蚯蚓粪处理的活性、中活性和高活性有机碳含量均显著升高。VC+CF的活性有机碳含量与CPMI明显高于其它处理,较CF分别高出30.38%和36.69;同时,微生物量碳、氮含量亦显著高于其它处理。此外,VC+CF还明显增强了土壤微生物呼吸作用,但降低了代谢熵,其中土壤微生物呼吸分别比CK、CF和VC提高64.91%、36.23%和16.05%,而代谢熵分别下降10.85%、9.06%和5.32%。与VC+CF相比,VC对豇豆土壤的影响作用较小。相关性分析表明,土壤不同程度的活性有机碳、CPMI与微生物活性之间呈显著或极显著的相关性,各指标之间具有密切的内在联系。综上所述,蚯蚓粪与化肥配施能明显提高豇豆土壤的活性有机碳含量,且能显著增强土壤微生物活性。该研究为豇豆的合理施肥提供了理论依据。     

阿特拉津除草剂对土壤微生物生态特征的影响

采用实验室培养试验研究了阿特拉津除草剂对土壤微生物生态特征的影响。结果表明：阿特拉津除草剂10mg／kg浓度处理释放的CO2与对照无明显差异,根据危害系数法的分级方法,其属于无实际危害级农药;阿特拉津除草剂10mg／kg浓度处理在初始阶段,明显降低土壤微生物生物量碳和微生物生物量氮,随培养时间推移土壤微生物生物量碳和生物量氮有所恢复,随后又有所下降,30d后土壤微生物生物量变化趋于平缓;阿特拉津除草剂对土壤微生物多样性产生一定影响．其影响随培养时间而异。在一定程度上反映出土壤微生物生态特征指标可作为除草剂污染土壤环境质量变异的参考指标。     

竹豆间种对柑橘园土壤化学性质及微生物碳源代谢特征的影响

选择红壤丘陵区典型柑橘园,设置清耕、自然生草和竹豆间种3 种种植模式,研究不同种植模式下柑橘园土壤化学性质、微生物生物量、微生物碳源代谢特征变化,并探明主导碳源代谢特征变化的土壤环境因素。结果表明,相对于清耕和自然生草种植模式,竹豆间种模式下柑橘园土壤pH 提高了24.03% 和21.65%,有机碳、碱解氮、有效磷、速效钾分别提高了19.40% 和25.14%、14.02% 和18.61%、2.69 和3.12 倍、63.40% 和1.14 倍。柑橘园土壤微生物生物量碳受种植模式影响不显著,但是竹豆间种显著提高了土壤微生物碳源利用能力(Average well colordevelopment,AWCD)和均匀度指数。竹豆间种模式下土壤微生物对于酰胺、氨基酸、酚类和多聚物等多个大类碳源的代谢强度显著高于其他处理,清耕模式下土壤微生物对于糖类尤其是赤藓糖醇、葡萄糖-1- 磷酸、D- 纤维二糖的代谢强度显著高于其他处理。逐步回归分析结果表明,微生物的碳源利用能力和土壤有机碳密切相关,而pH是影响微生物功能多样性及多个特异性碳源代谢强度的首要因素。冗余分析结果表明,柑橘园土壤微生物碳源利用模式受土壤环境因素影响的大小顺序为:pH> 有效磷> 碱解氮> 有机碳> 速效钾。因此,竹豆间种能够缓解柑橘园土壤酸化,提高土壤养分含量,改善微生物群落结构和功能多样性,有利于柑橘园土壤生态健康和可持续利用。     

铅污染对青紫泥微生物活性的影响

土壤微生物量碳、基础呼吸作用、土壤代谢商是表征土壤质量的重要指标,并且与土壤本身的理化性质有关。脱氢酶活性是土壤微生物种群及其活性的重要敏感性指标之一。通过室内培养,研究了不同铅添加水平(200~1 200 mg/kg)对青紫泥田微生物生物量碳及土壤基础呼吸作用、土壤代谢商、土壤脱氢酶的影响。研究表明:随培养时间延长,青紫泥田生物量碳呈下降趋势,基础呼吸作用随铅浓度升高而加强。土壤代谢商随培养时间延长变化趋势不同。外源铅胁迫下土壤脱氢酶活性随铅处理浓度升高明显受抑制。相关分析表明,土壤铅含量与土壤微生物生物量碳、脱氢酶在不同培养时期相关性不同。     

Evaluation of the Effects of Soil Depth on Microbial Activity in Three Agroecosystems in Venezuela

The objective of this study was to determine the total organic carbon (TOC), basal respiration (BR), microbial biomass carbon (MBC), the metabolic quotient (qCO₂), and ratio of microbial biomass carbon to total organic carbon (MBC/TOC) at different soil depths in three agroecosystems in Fundo Zamorano Independencia, Cojedes State, Venezuela. The types of agroecosystems studied were short-cycle corn and bean cropland, pastureland, and gallery forest, which was used as the control soil. The BR was determined by measuring the carbon dioxide released in a closed system, and the MBC was analyzed by applying the substrate-induced respiration method. The BR and the MBC varied depending on depth and transect position, decreasing between 18% and 38% at a depth of >10 cm with respect to the measurements taken between 0 and 10 cm. Significantly greater BR and MBC values were found at the middle transect position, where the soils with the greatest moisture content are located. No significant differences for BR, MBC, and qCO₂ values were found among the agroecosystems. This was due to the high spatial variability of the physical and chemical properties of the soils in the study site. However, with the application of the Kruskal–Wallis test, significant differences for the TOC and MBC/TOC values were found among the agroecosystems. These results highlight the importance of the type of plant cover over soil in different agroecosystems, mainly on pastureland, which maintains the potential of the inocular mycorrhizal of the soil.     

滦河上游不同密度油松林水源涵养功能研究

为了探知不同密度油松林人工林的水源涵养功能高低,选取木兰围场8个密度油松林的枯落物与土壤进行研究,利用水源涵养指数来比较各林分的水源涵养功能的高低,结果表明:（1）枯落物重量与有效拦蓄量变化趋势是随着密度的增加而增大,而枯落物最大持水量处于自身重量的2～4倍,最大持水率在250.61%～310.66%。（2）随着密度的增加土壤的最大持水量、非毛管孔隙度与非毛管蓄水量都是先是增加后减小,而最大持水量在1 800株/hm²达到了最大值为2 868.0 t/hm²;毛管孔隙度、毛管蓄水量与总孔隙度都没有明显的规律可言。（3）随密度的增加油松的水源涵养指数是呈现增加趋势的,其中的最大值是最小值的1.35倍,当密度处于1 500株/hm²时,指数趋于稳定,在1 500～1 800株/hm²时水源涵养指数较高。     

植茶年龄对茶园土壤微生物特性及酶活性的影响

分析了浙江省两个典型茶区土壤化学、微生物学性质以及酶活性。结果表明,茶园土壤的酸化程度随植茶年龄的增加而加重,土壤有效态N以NO-3 N为主。两茶区高龄茶园的土壤微生物量均很低,表明长期植茶形成的独特生态环境对微生物有抑制作用。两茶园土壤微生物代谢商(Rmic/Cmic)都较非茶园对照土壤低,并且随植茶年龄的增加,两者呈相似的变化趋势。土壤微生物商的变化可能与茶园土壤环境胁迫状况有关,低龄茶园的土壤微生物商(Cmic/Corg)高于非茶园对照土壤,也明显高于高龄茶园。土壤有机碳,全N ,有效P ,NH-4 N ,NO-3 N ,脲酶和酸性磷酸酶活性均随植茶年龄的增加而增加,而与土壤pH值呈相反的变化趋势     

Microbial biomass and soil organic carbon accumulation on a former lakebed near Novosibirsk,Russia

Shrinking of Lake Chany in W Siberia exposed 10,000 km² of former lakebed. On this new land we studied a chronosequence of young soils. The fraction of microbial C in total organic C had stabilized at 3% after 30 to 40 y. Concentration of organic C increased within the first 50 to 100 y to 4–5% in the first 10 cm, and to 2–3% at 10–20 cm depth. The amount of sequestered C is equivalent to about 2.5 d of current anthropogenic CO₂ emissions.     

保水剂施用量对杨树苗土壤物理性状与微生物活性的影响

[目的]探讨保水剂不同施用量对杨树土壤物理性状与微生物活性的作用效果,为中国杨树人工林节水高产实践模式提供理论依据与技术参考。[方法]研究CK(常规灌量)、CL(60%常规灌量配施10g保水剂)、CM(60%常规灌量配施30g保水剂)和CH(60%常规灌量配施50g保水剂)4个处理对杨树苗土壤物理性状、水稳性团粒结构、微生物数量、微生物呼吸和代谢熵的影响。[结果]同CK相比,CM处理显著降低了土壤容重,并明显提高了非毛管孔隙度,其中土壤容重分别较CK,CL和CH处理显著下降13.71%,5.31%和7.76%;还明显促进了土壤大团聚体(0.25mm团粒)的形成。同时,CM处理明显增加了土壤微生物总量和微生物量碳、氮含量,并显著增强了土壤微生物呼吸作用,其微生物呼吸速率分别比CK,CL和CH处理提高30.77%,11.84%和7.59%。此外,CM处理还降低了代谢熵,分别较CK,CL和CH处理下降4.81%,8.29%和9.74%。[结论]适宜的节水灌溉措施(60%常规灌量与30g保水剂组合)有助于改善杨树苗土壤的物理环境,并增强微生物活性。     

辽河源不同林龄油松林水源涵养能力研究

为定量评价不同林龄油松林的水源涵养能力,采用水量平衡法和综合蓄水量法,对辽河源地区3种不同林龄油松林的降雨再分配、凋落物持水能力、土壤蓄水能力以及林分水源涵养能力进行研究。结果表明:(1)观测期间,共观测到112次降雨,累计降雨量902.2mm,平均降雨量8.1mm;小雨、中雨、大雨和暴雨分别占总降雨量的25.2%,35.5%,26.4%和12.9%;(2)不同林龄油松林的林冠截留、林内降雨和树干茎流占总降雨量的比例分别为24.1%,72.9%和3%;林内降雨与林外降雨呈显著正线性关系;随着林龄的增加,林冠截留能力增加,而树干茎流先增加后减少;(3)凋落物的最大持水量、最大吸湿比和有效拦蓄量均随着林龄的增加而增加;(4)随着林龄的增加,土壤容重减小,总孔隙度增加,土壤入渗速率提高,蓄水能力增加;(5)不同林龄油松林水源涵养能力表现为成熟林近熟林中龄林。在不同林龄的油松林中,随着演替的进行,林分对降雨的分配与截流能力、水源涵养能力逐步增强。     

Influence of vegetation types and soil properties on microbial biomass carbon and metabolic quotients in temperate volcanic and tropical forest soils

Abstract

There is limited knowledge about the differences in carbon availability and metabolic quotients in temperate volcanic and tropical forest soils, and associated key influencing factors. Forest soils at various depths were sampled under a tropical rainforest and adjacent tea garden after clear-cutting, and under three temperate forests developed on a volcanic soil (e.g. Betula ermanii and Picea jezoensis, and Pinus koraiensis mainly mixed with Tilia amurensis, Fraxinus mandshurica and Quercus mongolica), to study soil microbial biomass carbon (MBC) concentration and metabolic quotients (qCO₂, CO₂-C/biomass-C). Soil MBC concentration and CO₂ evolution were measured over 7-day and 21-day incubation periods, respectively, along with the main properties of the soils. On the basis of soil total C, both CO₂ evolution and MBC concentrations appeared to decrease with increasing soil depth. There was a maximal qCO₂ in the 0–2.5 cm soil under each forest stand. Neither incubation period affected the CO₂ evolution rates, but incubation period did induce a significant difference in MBC concentration and qCO₂ in tea soil and Picea jezoensis forest soil. The conversion of a tropical rainforest to a tea garden reduced the CO₂ evolution and increased the qCO₂ in soil. Comparing temperate and tropical forests, the results show that both Pinus koraiensis mixed with hardwoods and rainforest soil at less than 20 cm depth had a larger MBC concentration relative to soil total C and a lower qCO₂ during both incubation periods, suggesting that microbial communities in both soils were more efficient in carbon use than communities in the other soils. Factor and regression analysis indicated that the 85% variation of the qCO₂ in forest soils could be explained by soil properties such as the C:N ratio and the concentration of water soluble organic C and exchangeable Al (P < 0.001). The qCO₂ values in forest soils, particularly in temperate volcanic forest soils, decreased with an increasing Al/C ratio in water-soluble organic matter. Soil properties, such as exchangeable Ca, Mg and Al and water-soluble organic C:N ratio, were associated with the variation of MBC. Thus, MBC concentrations and qCO₂ of the soils are useful soil parameters for studying soil C availability and microbial utilization efficiency under temperate and tropical forests.     

自然培养条件下全球变暖对山毛榉林土壤微生物活性的影响

Microbial activity in soil is known to be controlled by various factors. However, the operating mechanisms have not yet been clearly identified, particularly under climate change conditions, although they are crucial for understanding carbon dynamics in terrestrial ecosystems. In this study, a natural incubation experiment was carried out using intact soil cores transferred from high altitude(1 500 m) to low(900 m) altitude to mimic climate change scenarios in a typical cold-temperate mountainous area in Japan. Soil microbial activities, indicated by substrate-induced respiration(SIR) and metabolic quotient(q CO2), together with soil physicalchemical properties(abiotic factors) and soil functional enzyme and microbial properties(biotic factors), were investigated throughout the growing season in 2013. Results of principal component analysis(PCA) indicated that soil microbial biomass carbon(MBC) andβ-glucosidase activity were the most important factors characterizing the responses of soil microbes to global warming. Although there was a statistical difference of 2.82 ℃ between the two altitudes, such variations in soil physical-chemical properties did not show any remarkable effect on soil microbial activities, suggesting that they might indirectly impact carbon dynamics through biotic factors such as soil functional enzymes. It was also found that the biotic factors mainly controlled soil microbial activities at elevated temperature,which might trigger the inner soil dynamics to respond to the changing environment. Future studies should hence take more biotic variables into account for accurately projecting the responses of soil metabolic activities to climate change.