Effects of irrigation and plowing on soil carbon dioxide efflux in a poplar plantation chronosequence in northwest China

Soil respiration in forest plantations can be greatly affected by management practices. Irrigation is necessary for high productivity of poplar plantations in semi-arid northwest China. Moreover, plowing is essential for improving soil quality and reducing evaporation. In the present study, the influences of irrigation and plowing on soil carbon dioxide (CO₂) efflux were investigated in poplar plantations in 2007 and 2008. The experiments included three stand age classes receiving three treatments: control, irrigation, and plowing. Mean soil respiration in irrigation treatment stands was 5.47, 4.86, and 4.43?µmol?m^?2?s^?1 in 3-, 8-, and 15-year-old stands, respectively, during the growing season. In contrast, mean soil respiration in control stands was 3.71, 3.83, and 3.98?µmol?m^?2?s^?1 in 3-, 8-, and 15-year-old stands, respectively. During the entire observation period, mean soil respiration in plowing treatment stands increased by 36.2% compared with that in the control stands. Mean soil respiration in irrigation treatment stands was significantly higher than that in the control stands; this was mainly because fine root growth and decomposer activities were greatly depressed by soil drought, since natural precipitation could not meet their water demands. The results also suggest that plowing management can greatly increase soil CO₂ emission by modifying soil structure. After plowing, soil bulk density decreased and soil aeration was greatly improved, leading to greater rates of oxidation and mineralization.     

Red alder (Alnus rubra) alters community-level soil microbial function in conifer forests of the Pacific Northwest, USA

Nitrogen-fixing tree species have been shown to improve site fertility and increase N transformation rates, but the influence of N-fixing plants on the soil microbial community as a whole is largely unknown. We used patterns of individual carbon-source utilization and enzyme activities to assess the relative effects of N-fixing red alder on the soil microbial community in three adjacent stands (pure conifer, mixed alder-conifer, and pure alder) of a highly productive coastal Oregon forest where the density of red alder has been experimentally manipulated for over 65 years. Two major patterns were revealed: (1) bacterial and fungal carbon-source utilization patterns in soil from pure conifer stands were significantly different from both pure alder soils and mixed conifer-alder soils, while there was no difference in substrate utilization patterns between soils from the mixed alder-conifer and pure alder stands; and (2) the activities of nine extracellular enzymes involved in ligno-cellulose degradation and the mineralization of organic nitrogen, phosphate, and sulfate compounds were all significantly greater in pure alder soils compared to either pure conifer or mixed conifer-alder soils. Our results show that, in addition to an overall increase in soil fertility, microbial biomass, and microbial activity, the presence of N-fixing red alder significantly alters the physiological profile of the microbial community-even in an ecosystem already of high N status.     

Microbial biomass and C and N transformations in forest floors under European beech, sessile oak, Norway spruce and Douglas-fir at four temperate forest sites

The purpose of this research was to compare soil chemistry, microbially mediated carbon (C) and nitrogen (N) transformations and microbial biomass in forest floors under European beech (Fagus sylvatica L.), sessile oak (Quercus petraea (Mattuschka) Lieblein), Norway spruce (Picea abies (L.) Karst) and Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) at four study sites. We measured soil chemical characteristics, net N mineralization, potential and relative nitrification, basal respiration, microbial and metabolic quotient and microbial biomass C and N under monoculture stands at all sites (one mixed stand). Tree species affected soil chemistry, microbial activities and biomass, but these effects varied between sites. Our results indicated that the effect of tree species on net N mineralization was likely to be mediated through their effect on soil microbial biomass, reflecting their influence on organic matter content and carbon availability. Differences in potential nitrification and relative nitrification might be related to the presence of ground vegetation through its influence on soil NH₄ and labile C availability. Our findings highlight the need to study the effects of tree species on microbial activities at several sites to elucidate complex N cycle interactions between tree species, ground vegetation, soil characteristics and microbial processes.     

Linking the abundance of aspen with soil faunal communities and rates of belowground processes within single stands of mixed aspen–black spruce

The occurrence of aspen (Populus tremuloides Michx.) patches within stands dominated by black spruce (Picea mariana Mill. BSP) has been shown to increase litter decomposition and nutrient cycling rates by improving soil physical and chemical properties. It is well known, however, that these processes are also influenced by the structure of the soil biota, but this factor has received less attention. In this study, relationships between forest floor properties and soil invertebrates were studied along black spruce–trembling aspen gradients in three stands of the eastern boreal forest of Canada. The forest floor layer of 36 plots differing in aspen basal area was sampled and analyzed to determine physical and chemical properties, the rates of decomposition of standard substrates, net N mineralization, as well as microbial basal respiration and metabolic quotient. Soil invertebrates were also collected using funnel-extraction and pitfall trapping methods. Based on redundancy analyses, we found that forest floor properties, the abundance and composition of soil invertebrates, and the rates of belowground processes changed along the spruce–aspen gradient. The increase in aspen basal area was associated with a reduction in forest floor thickness, moisture content and microbial biomass, and with an increase in the concentration of nutrients. It was also accompanied by changes in soil faunal communities, as soil invertebrates were associated with specific soil properties. In general, macroinvertebrates (i.e., Lumbricidae, Formicidae, Carabidae, Staphylinidae and Gastropoda) were related to the nutrient-rich forest floor associated with aspen, whereas microarthropods and Enchytraeidae tended to be negatively related to aspen basal area. According to mixed linear models, decomposition rates of standard substrates and net ammonification significantly increased along the spruce–aspen gradient. Given the functional significance of macroinvertebrates in soils, these results suggest that aspen favours the elaboration of a macrofaunal community, which in turn accelerates the rate of soil processes by having either direct or indirect influence on microbial activity. Moreover, this study shows that the changes in soil processes and in the biodiversity of soil organisms related to the presence of mixed stands can operate only in the immediate surroundings of a given tree species. Therefore, coarse-scale tree species mixing in a forest stand may have a different effect on soil biodiversity and soil processes than fine-scale mixing.     

Soil chemical properties and nutritional status of trees in pure and mixed‐species stands in south Ethiopia

Interest in mixed‐species plantations in the tropics has increased because they appear to provide a wider range of options, such as yield, biodiversity, nutrient cycling, and C sequestration than pure stands. Pure stands of Pinus patula Schlecht. and Charm., Juniperus procera Hochst., and Grevillea robusta A. Cunn., and mixed stands of P. patula/G. robusta, P. patula/J. procera, and P. patula/Podocarpus falcatus R. Br. at Wondo Genet in S Ethiopia were studied to examine (1) the impact of mixed‐species plantations on soil chemical properties, and (2) the impact of mixed‐species plantations on the nutritional status of constituent trees. Soil (0–50 cm depth) and foliage samples were collected from four random plots (100 m²) in each of the pure and mixed‐species plantations. Soil samples were analyzed for organic C, N, and base cations. Foliage samples were analyzed for nutrients (N, P, K, Ca, and Mg). There were little significant differences in soil chemical properties and foliar nutrient concentrations of trees between the pure and mixed stands. Among pure stands, J. procera and G. robusta differed in soil exchangeable Ca⁺⁺ and K⁺ at 0–5 cm soil depth and in foliar P and Ca concentration. After 18 and 24 y, mixed stands did not influence soil chemical properties and tree nutrition differently than pure stands. This may be due to additive interaction in mixed‐species stands and the similarity of the constituent tree species in foliar nutrient concentration and their impact on soil chemical properties.     

大兴安岭林区落叶松林地不同发育阶段土壤肥力演变与评价

 以大兴安岭林区不同发育阶段兴安落叶松人工林和天然次生林为研究对象,采用野外调查和定量分析相结合的方法,对林地土壤有机质、土壤腐殖质组成、土壤酸度指标及其主要养分含量的变化进行测定和分析。利用主成分分析的方法,以各主成分特征贡献率为权重,加权计算各林地土壤肥力综合指标值。结果表明:随着林龄的增长,不同发育阶段落叶松人工林土壤酸度总体呈现升高的趋势,土壤有酸化的迹象;全磷和速效钾呈现降低的趋势;有机质、水解氮、胡敏酸和胡敏素含量在近熟林略有升高,但总体呈现降低的趋势。土壤肥力评价结果为:天然林>幼龄林>近熟林>中龄林>成熟林,即随着林龄的增长,土壤肥力迅速下降,其主要原因是林地凋落物分解缓慢。因此,建议通过适度提高林地抚育强度,调整群落结构,增加林地光照,诱导天然阔叶树种进入,形成针阔混交林的调控措施,调节落叶松人工纯林凋落物分解与积累的矛盾,以维持地力平衡和提高林地生产力。     

退化生态系统植被恢复过程中土壤微生物群落活性响应

通过分析退化生态系统中主要植被恢复类型对土壤微生物群落活性的影响,探讨敏感和可靠的微生物群落活性响应指标,揭示适合当地生态条件的植被恢复类型。结果表明,沙米荒地、白沙蒿、柠条、沙冬青和人工乔木林地土壤微生物量C,N,P和微生物商、蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶均表现出显著差异(P<0.05)。在土壤各层内,除上层人工乔木林地土壤微生物量N相对较高外,柠条恢复草地土壤微生物量C,N,P都相对较高,沙米荒地均较低;土壤微生物商没有明显的趋势;人工乔木林地蔗糖酶和柠条恢复草地脲酶活性相对较高,过氧化氢酶和碱性磷酸酶活性没有明显的变化趋势,沙米荒地的蔗糖酶、脲酶和过氧化氢酶活性以及白沙蒿草地碱性磷酸酶活性较低。方差分析(ANOVA)显示,蔗糖酶、脲酶、过氧化氢酶和碱性磷酸酶与土壤有机质、全氮以及微生物量C,N,P之间呈显著相关关系;主成分分析(PCA)表明,土壤微生物量N,C,P和蔗糖酶、土壤微生物商基本反映了研究区植被恢复中土壤微生物群落活性的响应信息。不同植被恢复类型草地中土壤微生物群落活性的变化表明,柠条和人工乔木林是研究区域内适合当地生态条件的植被恢复类型。     

不同密度大叶相思人工林林下植物和土壤特性

对3种密度大叶相思人工林的林下植物和土壤特性进行了研究.结果表明,大叶相思人工林林下植物的总覆盖度为:低密度林分(1 667株/hm2)＞中密度林分(4 444株/hm2)＞高密度林分(10 000株/hm2).林下植物总生物量呈现:低密度林分＞中密度林分＞高密度林分,低密度林分的灌木生物量最高,中密度林分的草本生物量最高.低、中、高密度林分的林下灌木层的Simpson多样性指数分别为0.679,0.935和0.708,草本层分别为0.837,0.678和0.789;灌木层的Shannon-Wiener多样性指数分别为1.657,0.535和1.171,草本层分别为0.904,1.228和1.064;灌木层的Pielou均匀度指数分别为0.691,0.333和0.654,草本层的分别为0.504,0.886和0.594.除有效P外,低密度和中密度林分的土壤特性优于高密度林分.     

潮土条件下长期施肥对作物产量、氮吸收与土壤剖面中硝酸盐含量分布的影响

Soil properties were investigated in sites where three succeeding generations of Chinese fir (Cunninghamia lanceolata (Lambert) Hooker) in Nanping, Fujian, China, were cultivated in order to show the impact of a repeated monoculture on site productivity. Compared with the first generation (FG) stand the soil structure deteriorated in the second generation (SG) and the third generation (TG) stands. For instance, the destruction rate of the peds increased by 55%-115% in the SG and the TG stands compared to the FG stand. Soil nutrient storage and nutrient availability also decreased in the SG and the TG stands. For surface soils of 0-20 cm, the organic matter content, total N and P, and available N and P decreased by 3%-20% relative to those in the FG stand. For many soil parameters, the differences between the FG stand and the SG and the TG stands were statistically significant (LSD test, P < 0.05). Furthermore, with each succeeding generation of Chinese fir, the total number of soil microbes declined, the soil enzyme activity weakened, and the soil biological activity decreased. In order to maintain sustainable site productivity, new silvicultural practices need to be developed for management of Chinese fir plantations.     

Non-linear impacts of Eucalyptus plantation stand age on soil microbial metabolic diversity

Purpose

Although it is generally accepted that planting exotic plant species alters metabolic function of soil microbial communities, its temporal dynamic is often ignored when evaluating ecological effects of associated land use changes. To investigate the dynamic impacts of successive Eucalyptus planting on carbon metabolic activities of soil microbial communities, we studied community-level physiological profiles of soil microbial communities in different generations of Eucalyptus plantations.

Materials and methods

We studied community-level physiological profiles of soil microbial communities, using the Biolog? Ecoplates incubation, in adjacent first (G1), second (G2), third (G3), and fourth (G4) generation Eucalyptus plantations that were, respectively, aged 3, 8, 14, and 19 years in Guangxi province, southern China. We used the ‘space-for-time substitution’ approach to investigate the impact of stand age of exotic Eucalyptus plantations on carbon metabolic diversity and activities of soil microbial communities. For each Eucalyptus plantation generation, three experimental plots were randomly selected. In each plot, one composite soil sample from 0 to 10 cm in depth was obtained for the analyses.

Results and discussion

Single carbon source utilization varied with Eucalyptus plantation stand age. Among preselected 31 carbon sources, utilization of 17 carbon sources changed significantly, which was best described by a quadratic function (ten carbon sources) and an exponential function (seven carbon sources). As a result, cumulative averaged metabolic activity and metabolic diversity of soil microbial communities showed quadratic and exponential changes relative to Eucalyptus plantation stand age. The order of cumulative averaged carbon metabolic activity and metabolic diversity were G1?>?G4, G3?>?G2 and G1?>?G2?>?G3, G4 (p?<?0.05), respectively. The factors contributing to carbon source utilization structure of soil microbial communities for different stand ages of Eucalyptus plantations were shrub richness, soil organic carbon content, microbial biomass carbon, C-to-N ratio, and N-to-P ratio.

Conclusions

Eucalyptus plantation stand age has inconsistent non-linear impacts on two aspects of soil microbial metabolic function: (1) quadratic impacts on carbon metabolic efficiency and (2) exponential impacts on carbon metabolic diversity. The decreasing carbon metabolic diversity has no significant impact on carbon metabolic efficiency during successive Eucalyptus plantings. The results show that the importance of assessing long-term impacts of land use changes on soil microbial communities from exotic plantations by quantifying multi-aspect non-linear changes on soil microbial metabolic function.     

吉林省东部低山丘陵区4种林分类型林地的土壤肥力分析

根据吉林省东部低山丘陵区汪清林业局金仓林场中4种主要林分类型(长白落叶松天然林、长白落叶松人工林、天然针阔混交林和天然阔叶混交林)的土壤肥力调查数据,分析和比较了4种林分类型林地的土壤物理和化学性质,并采用主成分分析评价了其土壤肥力状况。(1)随土壤深度增加,土壤容重和土壤pH值增大,而土壤含水量、阳离子交换量和养分含量减少,但其在不同林分下的变化程度不同;(2)林分类型对部分土壤化学性质(如土壤CEC、有机质、全氮和速效钾)影响显著。其中,天然针阔混交林的土壤含水量、土壤pH值、阳离子交换量、有机质含量及全氮、磷、钾含量均为最高;(3)采用主成分分析法对不同林分类型的林地土壤肥力状况进行了评价,结果发现土壤肥力状况为:天然针阔混交林>长白落叶松天然林>长白落叶松人工林>天然阔叶混交林。建议在经营现有的林分时,考虑近自然育林,及时进行林下补植更新,并营造针阔混交林,以改善该区林地土壤的肥力状况。     

Effects of forest stand type on oribatid mite (Acari: Oribatida) assemblages in a southwestern Quebec forest

Despite the ubiquity of oribatid mites in soil and litter systems, and their importance in decomposition and nutrient cycling processes, little is known of the factors underlying the composition of their assemblages. Our objective was to address this by determining how oribatid assemblage composition changes by forest stand type. This work was done in and near a hardwood forest in southwestern Quebec, Canada. We sampled mites by collecting 1 L of litter and 170 cm³ of soil from four sites in each of four distinct habitat types: American beech stands, sugar maple stands, mixed deciduous stands and mixed conifer plantations. Samples were collected in July and September 2005, and June 2006, and over 6500 oribatid mites were collected and identified to species. Abundance and species richness differed between forest types: for abundance conifer>beech>maple>mixed deciduous while for species richness beech and conifer>maple>mixed deciduous. Ordination analyses revealed that conifer plantations and beech stands supported distinct assemblages, while there were some overlap in the assemblages found in maple stands and mixed deciduous stands. These data support the importance of aboveground plant communities in affecting the composition of oribatid assemblages even at local scales and provide insight into additional impacts that may be caused by shifts in plant species ranges due to global changes.     

Temporal changes in soil carbon and nitrogen storage in a hybrid poplar chronosequence in northern Alberta

Sequestering C in biomass and soils in hybrid poplar plantations can help mitigate global climate change caused by the rising atmospheric CO₂ concentration. However, the impact of the establishment of hybrid poplar plantations on C and N storage and dynamics is poorly understood. We studied the distribution and temporal changes of C and N in soil organic matter (SOM) density fractions in 2-, 5-, 11-, and 13-year-old (age as in 2006) hybrid poplar stands that form a chronosequence by sampling the plantations in both 2004 and 2006. Sodium polytungstate (SPT, density = 1.6 g mL^- 1) was used to fractionate the soil into light (LF, density < 1.6 g mL^- 1), occluded light (LFo, density < 1.6 g mL^- 1) and heavy fractions (HF density > 1.6 g mL^- 1). The results showed that C and N concentrations (g kg^- 1 of fraction) in the SOM density fractions decreased in the order of LFo > LF > HF, while the C/N ratio was in the order of LF > LFo > HF. The amount of C and N stored in the LF, LFo and HF fractions and bulk soil in the top 10 cm of soil was: 149-504, 70-336, 1380-2876 and 1617-3776 g m^- 2, respectively, for C, and 6-26, 3-20, 149-271 and 152-299 g m^- 2, respectively, for N. From 2004 to 2006, C and N storage decreased in the LF and LFo fractions but increased in the HF fraction in the youngest stand. However, stand-age effects were likely muted by high inherent soil variability among the stands. Carbon storage in the light fraction was responsive in the short term to hybrid poplar plantation establishment.     

甘肃兴隆山自然保护区森林演替对土壤肥力影响的评价

以黄土高原半干旱区森林群落为研究对象,从土壤物理、化学和生物化学因子出发,利用模糊数学和因子分析方法对甘肃兴隆山植物群落演替过程土壤肥力的变化特征进行了综合评价。结果表明:4类林分土壤综合质量由高到低依次是落叶阔叶林、针阔混交林、灌木林、针叶林。证明随着森林群落演替进展,土壤肥力呈降低趋势。解决当前该区针叶林土壤退化的主要措施是利用人为干扰来控制生态演替,以维持地力平衡和提高林地生产力。     

Land restoration by fodder shrubs in a semi-arid agro-pastoral area of Morocco. Effects on soils

The present study assesses the effects of Atriplex nummularia Lindl. growth on soil chemical properties in a semi-arid area. The area is located in the Marrakech province (Morocco), in a degraded agropastoral region subjected to soil restoration actions based on fodder shrub plantations.     

青海大通退耕还林地林分水分生产力研究

 为了解青海东部黄土高原寒区退耕还林地人工林的水分生产力水平,2001—2003年对青海省大通县退耕还林的人工林进行了群落蒸散测算、标准地生物量调查和解析木分析,并研究了青杨灌木混交林、白桦紫果云杉混交林、华北落叶松纯林、紫果云杉纯林、白桦纯林等11种林分类型退耕还林人工林的林木水分生产力。结果表明:1)3 000株/hm2左右密度的林分是该区较为适宜的造林密度标准;2)在目前的技术经济水平条件下,2 1003333株/hm2密度的青杨灌木混交林成林、白桦纯林、紫果云杉纯林和白桦紫果云杉混交林水分生产效率居所有林分之首,其水分生产力指标可作为该地区常规造林技术条件下乔木成林的水分生产力标准;3)3000株/hm2左右密度的青杨灌木混交林、白桦紫果云杉混交林、紫果云杉纯林和白桦纯林成林的水分生产潜力基本达到了目前当地林木的最大生产能力。表明上述林分类型的造林模式可作为今后退耕还林工程和林业生态工程建设的发展方向。     

Soil microbial attributes along a chronosequence of Scots pine (Pinus sylvestris var. mongolica) plantations in northern China

Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.     

干旱荒漠区人工梭梭林土壤碳氮磷密度与生态化学计量特征

为了阐明人工梭梭林土壤碳氮磷密度及其生态化学计量特征演变规律,以吉兰泰荒漠区不同林龄(3,6,11,16年)人工梭梭林为研究对象,分析0—20,20—40,40—60 cm土层土壤有机碳(SOC)、全氮(TN)、全磷(TP)密度和生态化学计量特征。结果表明:(1)4种林龄人工梭梭林0—60 cm土层SOC、TN含量及其密度随林龄增加而升高,而TP含量及其密度随林龄增加而降低。其中,3,6年梭梭林SOC、TN含量及其密度随土层深度增加而升高,TP含量及其密度则与之相反;11,16年梭梭林SOC、TN、TP含量及其密度随土层深度增加而降低。(2)4种林龄梭梭林土壤C∶N、C∶P、N∶P分别为2.24~9.21,1.59~7.05,0.56~0.81,均属于中等变异水平,且变异系数随林龄和土层深度增加逐渐减小,说明土壤C∶N、C∶P、[JP]N∶P趋于平稳状态。(3)林龄、土层深度及其交互作用显著影响SOC含量、SOC密度、C∶N、C∶P,对TN含量、TP含量、TN密度、TP密度、N∶P无显著影响。(4)土壤孔隙度(STP)与SOC密度呈显著正相关关系(P＜0.05),说明土壤孔隙度增加有助于SOC密度增加,提高土壤肥力。在干旱荒漠区建植梭梭林有利于提高土壤肥力,改善干旱荒漠区土壤环境。     

土壤中汞的化学形态及其影响因素

An investigation and on 13-year-old(1984-1996) Chinese fir and Tsoong‘s tree mixed forests in Jianou City,Fujian Province,China was carried out to compare the influences of different interplanting types of individual tree-tree,row-row,row-strip(three rows)and pure Chinese fir stands on soil properties.Compared with the pure stands of Chinese fir ,the mixed stands exerted a posivtive effect on soil fertility,with increases in soil organic matter,total N,available P and available K.Moreover,improvements were also observed in soil enzymatic activities ,aggregate structure,structure,stability,status of soil porosity,soil aeration and penetrability in miexd stands.The row-row interplanted stands had the best effect on tree growth and soil properties among these mixed forests.In the southern subtropical region,the spreading of the row-row mixing model of the two tree species would be helpful to preventin ghe soil from fertility deterioratio caused by successive plantation of Chineses fir.     

The microbial biomass and activity in soil with shrub (Caragana korshinskii K.) plantation in the semi-arid loess plateau in China

Caragana korshinskii K. is a shrub species which is adapted to arid and semi-arid environments and plays an important role in soil protection. The objective of this study was to determine the influence of this shrub plantation on the soil ecosystem functions driven by microorganisms in the long-term. The changes in the size and activity of soil microbial biomass and the relationship between soil microbial biomass and chemical properties were investigated under shrub plantations aged 6, 18 and 26 years. The results showed that the pH value in the soil decreased gradually, while soil organic carbon (OC) and total nitrogen (TN) significantly increased with the age of C. korshinskii. Although microbial biomass carbon (MBC) and MBC/OC ratio gradually increased, the ratio of basal respiration to MBC (qCO₂) decreased with the age of C. korshinskii. The microbial biomass nitrogen (MBN) and MBC had a positive relationship with soil TN and OC, respectively. The flux of CO₂ decreased with the age of C. korshinskii which had a significant negative relationship with soil OC, TN, MBN and MBC. The results indicate that C. korshinskii plantations may help to improve microbially driven ecosystem functioning through long-term creation of resource-island.