Salinity effects on soil organic carbon and its labile fractions,and nematode communities in irrigated farmlands in an arid region,northwestern China

The effects of salinity on soil organic carbon （SOC） and its labile fractions including microbial biomass carbon （MBC） and easily oxidation organic carbon （EOC）, basal soil respiration, and soil nematode community in the Fluvents, an oasis in an arid region of northwestern China were investigated. Five sites were selected which had a salinity gradient with different groundwater table from 1.0 m to 4.0 m. Soils were sampled at the 0~0 cm plough layer from 25 irrigated fields of five sites and electrical conductivity was measured in the saturation paste extracts （ECe）. Soils were categorized into five salinity levels： （1） non-saline, （2） very slightly saline, （3） slightly saline, （4） moderately saline, and （5） strongly saline according to the values of ECe. The results show that SOC and total nitrogen concentration, cation exchange capacity （CEC）, and the concentrations of labile organic fractions （MBC, EOC）, and basal soil respiration decreased significantly with increasing ECe. The relationships between ECe and MBC, EOC and basal soil respiration were best described by power functions. Slight and moderate salinity had no significant impact on soil nematode abundance, but excessive salt accumulation led to a marked decline in soil nematode community diversity and abundance. Soil salinity changed soil nematode trophic groups and bacterivores were the most abundant trophic groups in salt-affected soils. Further study is necessary to identify the response of soil microbial processes and nematode community dynamics to soil salinity.

Four years of free-air CO_2 enrichment enhance soil C concentrations in a Chinese wheat field

Elevated atmospheric CO2 can influence soil C dynamics in agroecosystems. The effects of free-air CO2 enrichment （FACE） and N fertilization on soil organic C （Corg）, dissolved organic C （DOC）, microbial biomass C （Cmic） and soil basal respiration （SBR） were investigated in a Chinese wheat field after expose to elevated CO2 for four full years. The results indicated that elevated CO2 has stimulative effects on soil C concentrations regardless of N fertilization. Following the elevated CO2, the concentrations of Corg and SBR were increased at wheat jointing stage, and those of DOC and Cmic were enhanced obviously across the wheat jointing stage and the fallow period after wheat harvest. On the other hand, N fertilization did not significantly affect the content of soil C. Significant correlations were found among DOC, Cmic, and SBR in this study.

Land Use Effects on Soil Organic Carbon, Microbial Biomass and Microbial Activity in Changbai Mountains of Northeast China

Land use changes are known to alter soil organic carbon(SOC) and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Mountains of Northeast China is meager. Soil carbon content, microbial biomass carbon(MBC), basal respiration and soil carbon mineralization were studied in five selected types of land use: natural old-growth broad-leaved Korean pine mixed forest(NF); spruce plantation(SP) established following clear-cutting of NF; cropland(CL); ginseng farmland(GF) previously under NF; and a five-year Mongolian oak young forest(YF) reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicating low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineralized carbon and potentially mineralized carbon(C0) in NF were significantly higher than those in CL and GF, while no significant difference was observed between NF and SP. In addition, YF had higher values of C0 and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land(CL and GF) uses and plantation may lead to a reduction in soil nutrients(SOC and MBC) and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation of soil organic matter, which was reflected in the comparison of microbial indicators among CL, GF, and YF land uses. This study can provide data for evaluating soils nutrients under different land use types, and serve as references for the rational land use of natural forest in the study area.

A Comparative Study on the Microbiological Characteristics of Soils Under Different Land—Use Conditions from Karst Areas of Southwest China

Microbiological and physical\|chemical characteristics of subtropical forest, grassland and cropfield soils from the karst areas of Southwest China were investigated. The study revealed that the conversion of natural forest to other forms of land would lead to a reduction in soil organic C(26.2%-35.3%), total N(37.2%-55.8%), total P(32.9%-43.6%), microbial biomass C(35.4%-49.1%), N(37.2%-55.8%), and P(25.8%-41.9%). Comparative analysis of microbial activity in terms of basal soil respiration showed maximum activity in forest soil and minimum in cropfield soil. Analysis of microbial metabolic respiratory activity indicated a relatively greater respiratory loss of CO\-2—C per unit microbial biomass in cropfield and grassland than in forest soil. Considering the importance of microbial components in soil, it is concluded that land use in different ways will lead to the reduction of biological stability of soil.

Toxicity of cadmium to soil microbial biomass and its activity:Effect of incubation time on Cd ecological dose in a paddy soil

Cadmium (Cd) is ubiquitous in the human environment and has toxic effect on soil microbial biomass or its activity, including microbial biomass carbon (Cmic), dehydrogenase activity (DHA) and basal respiration (BR), etc., Cmic, DHA, BR were used as bioindicators of the toxic effect of Cd in soil. This study was conducted to determine the effects of Cd on soil microbial biomass and its activity in a paddy soil. The inhibition of microbial biomass and its activity by different Cd concentrations was described by the kinetic model (M1) and the sigmoid dose-response model (M2) in order to calculate three ecological doses of Cd: ED50, ED10 and ED5. Results showed that M2 was better fit than M1 for describing the ecological toxicity dose effect of cadmium on soil microbial biomass and its activity in a paddy soil. M2 for ED values (mg/kg soil) of Cmic, DHA, BR best fitted the measured paddy soil bioindicators. M2 showed that all ED values (mg/kg) increased in turn with increased incubation time. ED50, ED10 and ED5 of Cmic with M2 were increased in turn from 403.2, 141.1, 100.4 to 1000.7, 230.9, 144.8, respectively, after 10 d to 60 d of incubation. ED50, ED10 and ED5 of DHA with M2 increased in turn from 67.6, 6.2, 1.5 to 101.1, 50.9, 41.0, respectively, after 10 d to 60 d of incubation. ED50, ED10 and ED5 of BR with M2 increased in turn from 149.7, 6.5, 1.8 to 156.5, 50.8, 35.5, respectively, after 10 d to 60 d of incubation. So the ecological dose increased in turn with increased incubation time for M2 showed that toxicity of cadmium to soil microbial biomass and its activity was decreased with increased incubation time.

Soil Microbial Population in the Vicinity of the Bean Caper(Zygophyllum dumosum)Root Zone in a Desert System

The aim of the current study was to gain a better understanding of the changes in soil microbial biomass and basal respiration dynamics in the vicinity of the bean caper(Zygophyllum dumosum)perennial desert shrub and the inter-shrub sites.Microbial biomasses as well as basal respiration were found to be significantly greater in the soil samples taken beneath the Z.dumosum shrubs than from the inter-shrub sampling sites,with no differences between the two sampling layers(0-10 and 10-20 cm)throughout the study period.However,seasonal changes were observed due to autumn dew formation,which significantly affected microbial biomass and basal respiration in the upper-layer inter-shrub locations. The calculated metabolic coefficient(qCO_2)revealed significant differences between the two sampling sites as well as between the two soil layers,elucidating the abiotic effect between the sites throughout the study period.The substrate availability index was found to significantly demonstrate the differences between the two sites,elucidating the significant contribution of Z.dumosum in food source availability and in moderating harsh abiotic components.The importance of basal microbial parameters and the derived indices as tools demonstrated the importance and need for basic knowledge in understanding plant-soil interactions determined by an unpredictable and harsh desert environment.

施肥对我国农田土壤基础呼吸的影响

【目的】基础呼吸是反映土壤质量的重要指标,采用整合分析研究施肥对我国不同种植制度和气候带农田基础呼吸的影响程度及其关键控制因素,为探究土壤肥力提升提供科学依据。【方法】通过以“施肥”、“土壤呼吸”、“有机碳矿化”、“soil CO_(2)efflux/soil CO_(2)emission”、“农田”为关键词,在Web of Science、中国知网、万方数据库,收集2000-2020年发表的相关文献,建立了586组配对试验数据,对肥料类型、施肥年限、施氮量、气候带、种植制度、利用方式等条件下的土壤基础呼吸数据进行标准化,采用Meta-analysis分析了土壤理化性状和生产条件指标对土壤基础呼吸的影响程度。【结果】与不施肥相比,施肥对土壤基础呼吸的提高幅度平均为60.20%,其中,施用有机肥的提高幅度为81.45%,显著高于施用化肥的47.78%。当施肥年限大于30年时,施用有机肥对土壤基础呼吸的提升幅度是施用化肥处理的1.38倍。适宜氮肥投入量[N 100~200 kg/(hm^(2)·a)]引发的土壤基础呼吸增幅(72.56%)大于高量[>200 kg/(hm^(2)·a)]和低量[<100 kg/(hm^(2)·a)]氮肥投入的增幅(44.65%和55.21%)。中温带地区施肥导致的土壤基础呼吸增幅(93.71%)显著高于亚热带(37.11%)和暖温带(40.64%)地区,施用化肥和有机肥对中温带地区土壤基础呼吸的提升效果(73.88%和110.91%)显著高于对亚热带地区(28.99%和45.00%)。施肥对旱地土壤基础呼吸的提升幅度(105.01%)显著高于对水田(28.90%)和水旱轮作(46.90%)。轮作模式下施肥对基础呼吸的提升幅度(101.60%)显著高于连作模式(50.63%)。相关性分析结果表明,土壤基础呼吸与土壤有机碳、全氮及微生物生物量碳、氮呈显著正相关。此外,施用有机肥处理下,土壤基础呼吸与碱解氮和微生物熵呈显著正相关。【结论】施肥对农田土壤基础呼吸的作用受到施肥年限、氮肥投入量、气候带、土地利用类型、种植制度、土壤质地等因素的共同影响。施肥能够显著提升土壤有机碳含量,并提高土壤基础呼吸。在较长时间(>30年)尺度上,施用有机肥相较于化肥能够显著提高土壤微生物生物量碳以及微生物熵,进而提高土壤基础呼吸,表明施用有机肥对土壤质量提升有积极的促进作用。

黄土高原典型植物根际对土壤微生物生物量碳、氮、磷和基础呼吸的影响

选择黄土高原7种典型植物的根际与非根际土壤为研究对象,对土壤的养分含量、微生物生物量碳、氮、磷和基础呼吸的影响进行了初步研究。结果表明,7种不同植物根际土壤与非根际土壤的养分含量、微生物生物量和基础呼吸均存在显著差异;除冷蒿的土壤微生物生物量磷以外,其他各种植物的根际土壤的养分含量、微生物生物量和基础呼吸均比非根际土壤的高;土壤有机碳、全氮与土壤微生物生物量碳、氮及基础呼吸之间均具有极显著或显著相关关系,表明了土壤微生物生物量碳、氮可以作为判断土壤肥力状况的生物学指标,同时也可为提高土壤肥力水平和土壤培肥效果提供依据。

26年长期施肥对土壤微生物量碳、氮及土壤呼吸的影响

研究长期小麦连作施肥条件下土壤微生物量碳、氮,土壤呼吸的变化及其与土壤养分的相关性。以陕西长武长期定位试验为平台,应用氯仿熏蒸-K2SO4提取法、碱液吸收法和化学分析法分析了长达26a不同施肥处理农田土壤微生物量碳、微生物量氮和土壤呼吸之间的差异及其调控土壤肥力的作用。长期施肥及种植作物,均能提高土壤微生物量碳、氮含量,尤其是施用有机肥,土壤微生物量碳、氮含量高于单施无机肥的处理,土壤呼吸量也提高15.91%—75.73%,而施用无机肥对于土壤呼吸无促进作用。土壤微生物生物量碳氮、土壤呼吸与土壤有机质、全氮呈极显著相关。长期有机无机肥配施可以提高土壤微生物量碳氮、土壤呼吸,氮磷肥与厩肥配施对提高土壤肥力效果最好。微生物量碳氮及土壤呼吸可以反映土壤质量的变化,作为评价土壤肥力的生物学指标。

黄土丘陵区草地土壤微生物C、N及呼吸熵对植被恢复的响应

以野外样地调查和室内分析法研究了黄土丘陵区不同植被恢复年限下草地土壤微生物C、N及土壤呼吸熵的变化。结果表明,土壤微生物量碳明显地随着植被恢复年限的增加而增加。在恢复前23a,土壤微生物量碳在0～20cm土层年增加率为24.1%;20～40cm为104.4%。植被恢复23a后,0～20cm土层增长率为0.83%,20～40cm为0.19%。土壤微生物量N表现为在植被恢复的初期略有下降,3a后,开始出现明显增加。0～20cm土层年增长率为20.14%,20～40cm为15.11%。在植被恢复23a后,0～20cm土层的年增长率为0.14%,20～40cm变化不大。土壤微生物呼吸强度随着恢复年限的增加逐渐加强;土壤呼吸熵随植被封育时间的增加而呈对数降低趋势。土壤呼吸熵(qCO2)在反映土壤的生物质量变化时,显得更加稳定,受植物生长状况影响较小。相关分析表明,土壤微生物量和土壤微生物活性与土壤有机质、碱解氮和粘粒含量显著正相关;与土壤粉粒含量明显负相关;表层土壤pH值对其也有明显影响。草地植被自然恢复过程可增加土壤微生物活性,有利于土壤质量的提高。

腾格里沙漠植被重建对土壤呼吸的影响

植被重建是防止和控制沙漠化的有效措施之一。为探讨腾格里沙漠植被重建对土壤呼吸的影响,利用Li-6400-09土壤呼吸室于2007年观测了1989年建立的植被重建区和流沙区土壤呼吸差异,并采用根系隔离法区分了植被重建区的土壤基础呼吸和根际呼吸。结果表明,植被重建18a显著影响了该区土壤CO2的释放过程,总土壤呼吸速率由流沙区的CO20.107±0.008μmolm-2s-1显著增加到植被区CO20.483±0.033μmolm-2s-1,而且出现了较为明显的季节波动。植被重建不但导致根际呼吸速率增加,而且影响了土壤基础呼吸速率。此外,植被重建区灌木的缀块状分布格局和养分的空间异质性导致了土壤呼吸的空间差异。

水分条件对水稻土微生物群落多样性及活性的影响

采用BIOLOG碳素利用法、磷脂脂肪酸(PLFA)法和土壤酶活性测定等方法比较了三种水分条件(淹育、淹育晾干、非淹育)对水稻土微生物群落多样性及活性的影响。结果表明,淹育处理水稻土的脱氢酶、蔗糖酶活性明显高于淹育晾干和非淹育处理,并导致该土壤的基础呼吸升高。BIOLOG碳素利用法表明,非淹育处理的微生物群落平均吸光值(AWCD)显著低于淹育和淹育晾干处理。磷脂脂肪酸(PLFA)实验发现,淹育水稻土的真菌特征脂肪酸(18∶2w6,9c)所占比例减少,真菌特征脂肪酸(18∶2w6,9c)与细菌特征脂肪酸(15∶0i+15∶0a+16∶0i+16∶1w5c+17∶0i+17∶0a+17∶0cy+17∶0+18∶1w7c+19∶0cy)的比值下降;水分条件变化没有改变土壤微生物环丙基脂肪酸19∶0cy的相对丰度,但非淹育处理的环丙基脂肪酸17∶0cy相对丰度明显高于另外二种处理。BIOLOG碳素利用法的群落水平生理剖面(CLPP)和磷脂脂肪酸(PLFA)测定结果经聚类分析后,发现淹育和淹育晾干处理的土壤微生物多样性在较低的距离尺度可聚成一类,且与非淹育土壤具有明显差异。淹育水稻土与淹育晾干相比,尽管土壤微生物群落结构和功能多样性有一定的相似性,但微生物的种群组成和活性仍发生了较大的变化。

氮肥施用对玉米根际呼吸温度敏感性的影响

为研究氮肥施用对玉米根际呼吸和土壤基础呼吸温度敏感性的影响,采用动态密闭气室红外CO2分析法,于2010年进行田间试验,该试验设4个处理:裸地不施氮肥(CK)、裸地施氮肥(CK-N)、种植玉米不施加氮肥(M)、种植玉米施加氮肥(M-N),观测玉米田土壤呼吸各组分的日变化规律,同时观测土壤温度、气温等环境因子。结果表明,不种植玉米处理(CK和CK-N)土壤呼吸速率(土壤基础呼吸)为0.57～1.23μmol·m-2·s-1,施加氮肥对土壤基础呼吸没有显著影响;种植玉米条件下,施氮处理(M-N)的季节平均土壤呼吸速率为3.14μmol·m-2·s-1,显著高于不施氮处理(M),增幅达31.9%。CK和CK-N处理的土壤基础呼吸温度敏感系数Q10分别为1.20、1.25,而不施氮和施氮条件下玉米根际呼吸的Q10值则分别为1.27、1.49。施加氮肥导致玉米根际呼吸温度敏感性明显增强(Q10值增大),而土壤基础呼吸的温度敏感性则无明显变化,两种效应的叠加使得种植玉米土壤的总呼吸速率温度敏感性明显增加。

紫色土丘陵坡地恢复过程中土壤微生物生物量碳与水溶性有机碳变化特征

为了研究湖南省衡阳市紫色土丘陵坡地恢复过程中土壤微生物生物量碳（SMBC）与水溶性有机碳（SWSOC）的变化特征。采用空间序列代替时间序列的方法,选用立地条件基本相似的草坡阶段（GT）、草灌阶段（MT）、灌丛阶段（FX）、灌乔阶段（FA）、乔木阶段（AR）和顶极阶段（TV）,通过调查取样和试验分析,对不同恢复阶段的0～10,10～20和20～40cm土层土壤的SMBC、土壤微生物熵（SMQ）、SWSOC、水溶性有机碳与土壤有机碳的比值（SWSOC/SOC）、土壤基础呼吸（SBR）的变化规律以及他们与土壤理化性质的关系进行了研究。结果表明：SMBC和SBR随着土层深度的增加而减小,随着恢复的进行而增加;SMQ随着土层深度的增加和恢复进行而增加;在不同的恢复阶段,SWSOC均随着土层深度的增加而减小,在0～10cm土层,SWSOC随着恢复的进行而增加,在10～20和20～40cm土层,SWSOC随着恢复的进行先增后减;SWSOC/SOC随着土层深度的增加而增加,随着恢复的进行而减小;SMBC,SMQ,SWSOC,SBR均与土壤理化性质存在密切的相关性。研究表明,植被恢复有利于土壤质量的提高和土壤有机碳库的累积。

水稻土基底呼吸与CO_2排放强度的日动态及长期不同施肥下的变化

土壤呼吸排放是陆地生态系统土气交换快速而活跃的途径之一，对大气CO2浓度的变化有显著的影响。本文对太湖地区一个代表性水稻土水稻收割后土壤基底呼吸CO2排放进行了昼夜观测和采样分析。结果表明，不同小区平均土壤呼吸与CO2排放速率在CO2-C12．2～25．2mg／（m^2·h）之间，日排放量在CO2-C327．2～604．1mg／（m^2·d）之间，低于文献报道的森林和草地及旱作农田的土壤呼吸；与长期有机，无机配施处理相比，长期单施化肥CO2日排放量提高了55％～85％，并且显著提高了土壤呼吸对土壤（5cm）温度的响应敏感性。相关分析表明，土壤呼吸CO2排放强度与土壤微生物N（Nmic）、微生物C：N（Cmic／Nmic）和P的有效性有密切的关系；生物有效N和P的有效性显著地影响着土壤呼吸与CO2的生成和排放。本试验结果进一步支持了水稻土的固碳效应。但是：供试不同小区土壤呼吸排放强度的变异隐含着长期不同施肥处理可能使与高呼吸活性有关的微生物群落发生改变，有待于进一步研究。

不同施肥管理措施对土壤碳含量及基础呼吸的影响

连续7年试验研究了施用15t/hm2和7.5t/hm2有机肥(包括EM堆肥、EM鸡粪肥和传统堆肥)、化肥和对照处理对土壤碳含量与基础呼吸的影响,结果表明:随有机肥施用量的提高,土壤可溶性碳、总有机碳、微生物生物量碳和土壤的基础呼吸随之增加。施用化肥可一定程度提高土壤可溶性碳、总有机碳、微生物生物量碳和土壤的基础呼吸。不同施肥措施对土壤有机碳、微生物生物量碳和土壤基础呼吸的影响趋势为EM堆肥处理>传统堆肥处理>化肥处理>对照,施肥对土壤微生物代谢商的影响趋势为EM堆肥处理<传统堆肥处理<化肥处理<对照。土壤微生物生物量碳与可溶性碳、总有机碳及土壤基础呼吸之间呈极显著正相关。土壤微生物代谢商与土壤可溶性碳、总有机碳、微生物生物量碳及基础呼吸之间呈极显著负相关。

红壤茶树根层土壤基础呼吸作用和酶活性

对不同树龄茶树根层土壤的呼吸作用 (包括代谢熵 qCO2 )和土壤酶 (脲酶、转化酶和酸性磷酸单酯酶 )活性进行了研究 .不同树龄茶树根层土壤日基础呼吸作用强度 (3 6.2 3～ 5 8.5 2mg·kg-1·d-1)和日代谢熵 (0 .3 0～ 0 .68)都以 40和 90年茶树较为接近 ,分别显著大于和小于 10年树龄茶树根层土壤 ;脲酶活性 (41.48～ 47.72mg·kg-1·h-1)则三者间差异不大 ,虽然随树龄增长而下降 ;转化酶活性 (189.2 9～3 63 .40mg·kg-1·h-1)也随树龄增长而下降 ,并且 10年茶树根层土壤显著大于 40和 90年树龄茶树 ;而酸性磷酸单酯酶活性 (44 4.2 2～ 82 8.3 2mg·kg-1·h-1)相反 ,随树龄增长而增强 .结果表明 ,土壤基础呼吸作用、代谢熵和 3种土壤酶活性都与茶树树龄、土壤 pH、土壤有机碳、土壤全氮、土壤可溶性酚总量。

小麦和大豆茬口对黄瓜土壤微生物生态特征的影响

采用常规稀释平板法和BIOLOG ECO微平板反应系统,研究了小麦和大豆茬口对黄瓜土壤微生物生态特征的影响.结果表明,两种茬口均显著提高了黄瓜土壤微生物真菌、细菌和放线菌的数量,显著降低了尖孢镰刀菌黄瓜专化型的数量(P<0.05);显著提高了土壤微生物群落的Shannon-Wiener指数、均匀度指数、Simpson指数和McIntosh指数(P<0.05)、以及土壤微生物生物量碳,降低了土壤基础呼吸和代谢商(P<0.05),改变了土壤微生物对单一碳源的利用能力.此外,两种茬口还显著提高了土壤中速效磷和速效钾含量,以及黄瓜产量.说明小麦和大豆茬口改善了土壤微生态环境.

铅污染水稻土的微生物活性

采用盆栽试验方法,研究了受外源铅污染(0￣1 200 mg.kg-1)种植水稻后的青紫泥的微生物量碳、基础呼吸作用、代谢商及土壤脲酶、脱氢酶的变化,分析了外源铅污染的水稻土微生物学特性。结果表明,随培养时间延长,水稻土生物量碳呈下降趋势,基础呼吸作用随铅浓度升高而加强;土壤代谢商随铅浓度升高变化趋势不同;土壤脲酶、脱氢酶活性随铅处理浓度升高明显受抑制;土壤有效铅与土壤微生物生物量碳及土壤脲酶呈显著负相关。

喀斯特峰丛洼地土壤剖面微生物特性对植被和坡位的响应

选取广西环江县喀斯特峰丛洼地:草丛(T)、灌丛(S)、原生林(PF)(中坡位)不同植被类型,原生林上、中、下不同坡位,按土壤发生层采集淋溶层(A层,0—10 cm)、过渡层(AB层,20—30 cm,草丛和灌丛;30—50 cm,原生林)、淀积层(B层,70—100cm)样品,研究土壤微生物量碳、氮(Soil microbial biomass carbon(SMBC)、soil microbial biomass nitrogen(SMBN))、微生物碳熵、氮熵(ratio of SMBC to soil organic carbon(qMBC)、ratio of SMBN to soil total nitrogen(qMBN))、土壤基础呼吸(soil basicrespiration(SBR))以及代谢熵(microbial metabolic quotient(qCO2))的剖面分异特征及其影响因素。结果表明,植被、土层深度显著影响土壤微生物量及基础呼吸,随植被恢复,SMBC、SMBN、SBR由草丛、灌丛、原生林依次上升,并随土壤发生层位的加深逐渐减少,qCO2在3种植被类型间差异显著:T>PF>S;原生林A层SMBC,SMBN在各坡位间均显著高于AB层、B层,SBR在A层由下坡位至上坡位递减,而在AB和B层的上、下坡位间无显著差异,qCO2坡位间无显著差异(P>0.05);SMBC与SMBN之间存在显著正相关(r=0.825,P<0.01,n=45),且SMBC、SMBN、SBR分别与有机碳、全氮、碱解氮均呈显著正相关。因此,随植被恢复,土壤质量明显改善,且坡位对A层土壤的影响较AB层和B层更显著,对于维持土壤微生物调节的土壤养分循环功能,调控土壤氮素营养与土壤有机质同等重要,这为合理制订喀斯特生态恢复措施提供了理论依据。