Soil Fertility,Mineral Nitrogen,and Microbial Biomass in Upland Soils of the Central Amazon under Different Plant Covers

Amazon is the largest state in Brazil and majority of the state is covered by the largest tropical rainforest of the world. Most soils of the Amazon region soils are acidic and infertile. When the Amazon forest land is cleared for agricultural use by burning the vegetation, the efficient nutrient recycling mechanisms are disrupted. However, nutrient contents in the deforested burn land increased temporarily. The objective of this study was to evaluate the soil fertility, mineral nitrogen (N), and microbial activity of carbon (C), N, and phosphorus (P) resulting from the replacement of the primary forest with pasture (Brachiaria brizantha) and commercial plantations of rubber (Hevea spp.), cupuaçu (Theobroma grandiflorum), and citrus trees (Citrus sinensis) cultivated in Xanthic Ferralsol and secondary forest under Acrisols Dystric Nitosols. The results showed that ammonium-N predominates in the 0- to 10-cm soil depth in both primary forest and areas with secondary forest, citrus plantation, and pasture. There was no increase in soil fertility with management of the cultivated areas under the secondary forest, but in the pasture there was a significant increase in the stock of organic C and total N and high C/N ratios, the inverse of what occurred with the C of the microbial biomass. The primary forest had the greatest values of C and P of the microbial biomass and the lowest metabolic quotient. Of the successions studied, the rubber trees were the plant cover with the smallest changes in terms of quality of the organic matter in the soil.     

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.     

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.     

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。     

Consequences of forest conversion to pasture and fallow on soil microbial biomass and activity in the eastern Amazon

The main change in soil use in Amazonia is, after slash and burn deforestation followed by annual crops, the establishment of pastures. This conversion of forest to pasture induces changes in the carbon cycle, modifies soil organic matter content and quality and affects biological activity responsible for numerous biochemical and biological processes essential to ecosystem functioning. The aim of this study was to assess changes in microbial biomass and activity in fallow and pasture soils after forest clearing. The study was performed in smallholder settlements of eastern Brazilian Amazonia. Soil samples from depths of 0–2, 2–5 and 5–10 cm were gathered in native forest, fallow land 8–10 yr old and pastures with ages of 1–2, 5–7 and 10–12 yr. Once fallow began, soil microbial biomass and its activity showed little change. In contrast, conversion to pasture modified soil microbial functioning significantly. Microbial biomass and its basal respiration decreased markedly after pasture establishment and continued to decrease with pasture age. The increase in metabolic quotient in the first years of pasture indicated a disturbance in soil functioning. Our study confirms that microbial biomass is a sensitive indicator of soil disturbance caused by land‐use change.     

冀北辽河源油松天然林土壤微生物碳代谢特征研究

本文以冀北辽河源地区不同林龄油松天然林为研究对象,研究其土壤微生物生物量碳、微生物呼吸及微生物代谢熵随油松林龄的变化趋势。结果表明:随着油松天然林林龄的增加,土壤微生物生物量碳逐渐增加;而土壤微生物呼吸则呈现出先减小后增加的趋势;微生物代谢熵表现为随油松林林龄的增加而降低。相关性分析表明,土壤微生物生物量碳、微生物呼吸分别与微生物代谢熵之间呈现高度的极显著线性负相关。微生物生物量碳与微生物呼吸呈极显著正相关,但线性相关程度较弱。土壤微生物生物量碳和微生物呼吸与土壤温度和含水量均呈极显著正相关,而土壤微生物代谢熵则与土壤温度、土壤含水量呈极显著负相关。上述结果表明,在冀北辽河源地区,土壤微生物生物量碳、微生物呼吸、微生物代谢熵与油松天然林林龄密切相关。随着油松天然林林龄的增加,其土壤微生物活性增强,碳代谢效率增加,土壤质量及可持续利用潜力更高,土壤生态体系更加成熟。     

高效栽培雷竹林土壤重金属含量的分析研究

雷竹(Phyllostachyspraecox)是最近十几年发展起来的优良笋用竹种,近年来以重施肥和冬季地表覆盖增温为核心的高效栽培技术在生产上得到了大面积推广。为了解高效栽培雷竹林土壤重金属含量现状,采集了浙江省雷竹主产区40个样点土壤样品,利用ICP法分析了土壤重金属含量。结果表明,雷竹林土壤重金属镉(Cd)、铬(Cr)、铜(Cu)、铅(Pb)和锌(Zn)全量含量分别为0.23±0.11,68.23±25.61,23.26±6.61,12.47±2.86,108.50±54.92mg/kg,所有样点5种重金属全量均未出现超标现象。Cd、Cr、Cu、Pb和Zn有效态含量分别为0.028±0.025,0.150±0.102,3.482±1.304,1.636±1.022,10.814±9.767mg/kg,5种重金属有效态含量变异均明显大于全量。重金属Cd、Cu、Pb和Zn有效态含量占全量百分比较高。从不同栽培历史雷竹土壤重金属含量变化来看,Cu、Pb、Zn3种元素随着栽培历史延长,土壤中全量含量显著上升,其中Cu上升量最大,栽培历史从2～3年延长到8～10年,Cu含量增加了1.39倍。重金属Cd、Cu、Zn全量与有效态含量间具有显著或极显著相关性。     

黄土高原森林带土壤养分和微生物量及其生态化学计量变化特征

选择黄土高原森林带自东向西8个地区优势植物的土壤作为研究对象,探究不同经度下土壤养分和土壤微生物生物量生态化学计量特征。结果表明:土壤碳、氮和微生物生物量碳、氮、磷含量随经度整体呈现出先减少后增加的变化趋势,土壤微生物生物量碳氮磷与土壤碳氮之间存在耦合关系,对环境因子的响应具有一致性。土壤磷含量空间分布比较稳定。土壤碳氮比为8左右,土壤有机碳与全氮的空间分布具有一致性。土壤微生物生物量碳氮比为9左右,微生物生物量氮磷比为5左右,反映了土壤微生物生物量碳氮、氮磷的比值较稳定,但土壤微生物生物量碳磷比呈现出先增大后减小的变化趋势。土壤养分及土壤微生物量碳氮磷与土壤水分含量相关性较强。土壤养分与土壤微生物量碳氮磷及其生态化学计量是环境因子综合作用的结果。     

Functional Diversity and Size of Soil Microbial Communities Induced by Different Land Management Systems

Abstract

Soil microorganisms drive nutrients cycling to a great extent, and they play an essential role in maintaining a stable soil ecosystem and ensuring sustainable forestry development. Land management has been proven to be a real factor in influencing soil quality. The purpose of this study was to investigate the effects of different land management techniques on soil microbial communities. There were four types of land management systems selected for this study: natural masson pine, Phyllostachy pubescens, Phyllostachys praecox, and vegetable. Soils were sampled from these four systems and assayed for soil microbial biomass carbon (MBC), community level substrate utilization pattern, functional diversity, and principle component analysis. Values of MBC were significantly different (P<0.05) from one another in the order of masson pine>Phyllostachy pubescens>Phyllostachys Praecox>vegetable. Analysis of community level substrate utilization pattern indicated that carbon source utilization and total activity by soil microorganisms were greater under the masson pine system than the other three systems (P<0.01). The functional diversities of soil microbial communities characterized as Shannon and McIntosh indexes were much richer in soil under masson pine system; Shannon index was 4.483, 4.241, 4.224, and 3.938 and McIntosh index was 13.51, 7.332, 6.272, and 6.261 for natural masson pine, Phyllostachy pubescens. Phyllostachys praecox, and vegetable systems, respectively. The results from the principle components analysis (PCA), based on the data of optical density (OD) at 120 h of incubation, showed that the value of the first principal component (PC1) of soil for natural masson pine was greater (P<0.05) than those for the other three systems. The difference in scores of the second principal component (PC2) between Phyllostachy pubescens, Phyllostachys praecox, and vegetable were not statistically different. The size and activity of soil microbial communities generally decreased with soil depth, with significant differences in soil MBC, community level substrate utilization pattern, and functional diversity indexes found between A and C horizons (P<0.01). It was concluded that land management systems had a great influence on soil microbial biomass, activity, and functional diversity.     

味精废浆与化肥配施对杨树幼苗土壤活性有机碳与微生物活性的影响

为探讨味精废浆有机肥对林木土壤的生物学效应及确定味精废浆与化肥适宜的搭配比例,通过盆栽试验,研究了CK(对照,不施肥)、N100(尿素提供100%的氮)、M10N90(味精废浆和尿素分别提供10%与90%的氮)、M30N70(味精废浆和尿素分别提供30%与70%的氮)与M50N50(味精废浆和尿素各提供50%的氮)等处理对杨树幼苗土壤活性有机碳、碳库管理指数(CPMI)与微生物呼吸、代谢熵及生长的影响。结果表明:与N100处理相比,配施味精废浆处理的土壤活性、中活性和高活性有机碳含量均明显升高。M30N70处理的活性有机碳含量与CPMI显著高于其他处理,分别较N100处理高出34.78%和42.96;其微生物量碳、氮含量也明显高于其他处理。同时,M30N70处理还能显著增强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较CK、N100、M10N90和M50N50处理提高81.13%,35.21%,17.07%和5.49%,而代谢熵分别下降9.16%,10.37%,6.98%和5.80%。此外,M30N70处理的地径、苗高亦达最高值,并与其他处理差异达显著水平。同M30N70处理相比,M10N90与M50N50处理对杨树幼苗土壤及生长的影响效果较小。相关性分析表明,地径、苗高生长与土壤不同程度的活性有机碳、碳库管理指数及微生物活性有显著或极显著的相关性,各指标之间具有紧密的内在关联。综合分析认为,味精废浆与化肥以3∶7比例配施能显著提高杨树幼苗土壤的活性有机碳含量,明显增强土壤微生物活性,并促进其生长。     

不同经营类型红松林对汤旺河流域土壤性质的影响

通过实地调查与试验分析，研究了汤旺河流域4种经营类型红松林对土壤性质的影响情况。结果表明：在研究地区无论土壤pH、土壤有机质，还是土壤养分和土壤物理性质，白桦与红松天然更新形成的混变林和白桦与红松人工造林形成的混交林都较红松人工纯林优越，维护林分土壤地力及涵养水分的功能强。而红松人工纯林较原始红松林和两种白桦红松混交林维护地力及涵养水分功能弱。研究结果为汤旺河流域森林恢复与重建提供了科学合理的途径。     

不同施肥处理对三峡库区柑橘园土壤氮磷淋失影响

在2017年8月利用原状土柱模拟淋溶试验对三峡库区秭归县柑橘园土壤的氮磷淋溶流失进行研究,探讨不同施肥处理对土壤氮、磷淋失的影响,为三峡库区农业面源污染的防控提供理论依据。试验设置6个处理,分别为不施肥处理(T0)、减量施肥(T1)、常量施肥(T2)、增量施肥(T3)、常量复合肥A施肥(T4)和常量复合肥B施肥(T5)。结果表明:(1)不同施肥处理下,柑橘园土壤淋滤液中总氮(TN)、总磷(TP)、硝态氮(NO_3~-—N)和铵态氮(NH_4~+—N)的淋溶浓度范围分别为37.16~163.07,0.61~6.69,27.54~79.38,2.37~7.10mg/L。(2)施肥量和施肥种类皆为土壤中氮磷淋溶的影响因素。在相同施肥种类下,土壤氮磷淋溶浓度随施肥量增加而显著增加,但施肥量高到一定程度后,淋溶浓度增长幅度会降低。在相同施氮量下,硝态氮的淋失受施肥种类影响最大,铵态氮最小。(3)在土壤淋滤液中,硝态氮为可溶性氮主要淋失形态,其淋失量占TN淋失量的比率为29.72%~46.18%,NH_4~+—N淋失量的比重为1.09%~2.05%。从研究结果推论,常量复合肥A施肥处理更有利于肥料氮向供植物吸收可溶性氮转化并降低施肥后土壤中氮素累积的风险。     

洞庭湖区不同耕种方式下水稻土壤有机碳、全氮和全磷含量状况

在洞庭湖区的2km2典型样区内,按3个/hm2的密度采集土样,分析不同耕种方式下(水稻、水旱轮作油菜、水改旱种苎麻1~5年)水稻土壤的有机碳、全氮和全磷含量状况。结果表明,水稻田土壤有机碳、全氮和全磷含量水平均较高,水田改为旱地后土壤有机碳、全氮含量及C/N比值有较大幅度的下降,但全磷含量变化不大。土壤有机碳、全氮及C/N比值均以水稻田土壤>油菜地土壤>苎麻地土壤,与水稻田相比,油菜土壤有机碳平均下降了11.19%、全氮下降了10.33%,而苎麻土壤有机碳平均下降了35.57%、全氮下降了31.61%。土壤有机碳与全氮之间呈线性关系,相关性均达极显著水平(P<0.01)。     

Changes in Soil Aggregate-Associated Organic Carbon and Nitrogen after Ten Years under Different Land-Use and Soil-Management Systems in Indo-Gangetic Sodic Soil

A study was conducted to evaluate the effects of different land uses and soil-management systems (LU and SMS) on key soil physicochemical indicators [aggregate stability, distribution of soil organic carbon (SOC), and nitrogen (N) in aggregate fractions] and to interpret significance of long-term cultivation of agroforestry plantations [Prosopis juliflora L. (AFP) and Casuarina equisetifolia L. (AFC)], horticultural plantations [(Tamarindus indica (HI) and Syzygium cumini (HJ)], and rice–wheat system (RW) in sodic soil of the Indo-Gangetic plain. Soil samples collected from the different LU and SMS plots were analyzed. The barren sodic soil (BSS) exhibited the least mean weight aggregate diameter (0.21), whereas AFP recorded the greatest (0.59). Total N content in surface soil under RW system was about the same as AFP, AFC, HI, and HJ and significantly greater than BSS. Across the LU and SMS except BSS, microaggregates recorded a narrower C/N ratio than macro- and mesoaggregates.     

晋西黄土高原不同地类土壤抗冲性研究

以晋西黄土高原不同林龄的油松林地为研究对象,以荒草地和农地为对照,以地表径流的泥沙含量为指标,采用野外实地放水冲刷法,对不同林龄油松林地的土壤抗冲性进行研究,分析坡度、林龄、枯落物、生物多样性指数对土壤抗冲性的影响.结果表明:(1)油松林地的土壤抗冲性大于荒草地和农地的土壤抗冲性;(2)坡度对油松林地的土壤抗冲性有较大影响,土壤抗冲性随着坡度的增加而减弱;(3)在一定坡度下,随着林龄的增加土壤抗冲性增强;(4)枯落物对油松林地的土壤抗冲性有显著影响,去除枯落物的油松林地土壤抗冲性明显小于有枯落物的油松林地,土壤抗冲性随着枯落物厚度的增加而增强;(5)生物多样性和土壤抗冲性关系密切,林地土壤抗冲性随多样性指数的增大而增强.     

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。     

武夷山不同海拔典型森林土壤有机碳和全氮储量分布特征

为探究武夷山森林土壤碳氮储量的分布特征,以武夷山国家公园不同海拔高度(600,1 000,1 400 m)的典型森林土壤为研究对象,研究土壤有机碳和全氮含量及储量随海拔高度的变化规律,分析了影响土壤有机碳和全氮储量变化的因子。结果表明:随着海拔的升高,土壤有机碳和全氮的含量在0—5 cm土层和5—10 cm土层变化规律不同,5—10 cm土层的土壤碳氮含量随海拔变化趋势更为明显,而0—5 cm土层的土壤碳氮含量表现为1 000 m海拔较高; 海拔1 000 m的土壤C/N明显高于海拔1 400 m和600 m; 在土壤有机碳和全氮储量方面,1 400 m明显高于1 000 m和600 m,且高海拔区域土壤碳氮储量的变化幅度显著大于低海拔区域,两土层间差异不显著; 相关分析和RDA分析表明细根C/N和土壤温度是影响土壤有机碳和全氮储量的主导因子。综上所述,土壤有机碳和全氮的分布随海拔升高并非线性增长,受到气候、植被特征及土壤状况的综合影响,高海拔地区土壤碳氮储量对气候变化的响应更为敏感。     

Spatial Changes in Some Soil Properties Under Litchi and Mango Plantations

Abstract

To efficiently match crop demands, nutrient distribution under perennial horticultural trees needs to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary. Soil samples were collected around litchi (Litchi chinensis Sonn) and mango (Mangifera indica) trees at various distances (i.e., 1, 2, 3, 4, and 5 m) from the tree trunk at 0–0.15 m, 0.15–0.30 m, 0.30–0.60 m, and 0.60–0.90 m depths where recommended fertilizer doses have been applied. Results revealed that the soil pH was significantly lower under litchi plants than under mango plants. Both EC and OC were significantly higher under mango than under litchi. Surface layer had the maximum available potassium (K) and phosphorus (P). DTPA‐iron (Fe), manganese (Mn), and zinc (Zn) were significantly greater in soils under litchi trees than in soils under mango trees, whereas the reverse was true for DTPA‐copper (Cu).     

基于不同林分类型下土壤碳氮储量垂直分布

以辽东大伙房水库周边防护林典型林分针阔混交林(落叶松-油松-刺槐混交林)、油松林、落叶松林、刺槐林为研究对象,对其土壤养分含量进行测定,研究了不同林分土壤剖面上有机碳、全氮、有机碳储量的分布规律。结果表明:随着土层深度的增大,4种林分的土壤有机碳、全氮含量均逐渐降低;4种林分土壤剖面有机碳含量大小顺序为落叶松林(24.16g/kg)刺槐林(23.07g/kg)针阔混交林(16.06g/kg)油松林(15.76g/kg);全氮含量大小顺序为刺槐林(5.23g/kg)落叶松林(4.57g/kg)油松林(3.45g/kg)针阔混交林(2.42g/kg);C/N平均值大小顺序为落叶松林(7.36)针阔混交林(6.51)油松林(4.67)刺槐林(4.57);4个林分0-40cm土层的有机碳储量大小为落叶松林(112.94t/hm~2)刺槐林(107.40t/hm~2)针阔混交林(105.42t/hm~2)油松林(89.89t/hm~2);4种林分土壤pH无明显差别,各土层土壤pH随土层深度增加而增大;4种林分土壤容重由高到低顺序依次为针阔混交林(1.73g/cm~3)油松(1.65g/cm~3)落叶松(1.64g/cm~3)刺槐(1.56g/cm~3)。4个林分土壤有机碳含量与土壤全氮含量互相间均存在极显著正相关关系,土壤有机碳、全氮含量与C/N之间则没有明显相关关系;在针阔混交林中,土壤容重、土壤全氮含量和土壤pH与土壤有机碳之间存在线性数量关系,而其他纯林则没有这种关系。     

Soil biochemical and chemical changes in relation to mature spruce (Picea abies) forest conversion and regeneration

To investigate soil changes from forest conversion and regeneration, soil net N mineralization, potential nitrification, microbial biomass N, L‐asparaginase, L‐glutaminase, and other chemical and biological properties were examined in three adjacent stands: mature pure and dense Norway spruce (Picea abies (L.) Karst) (110 yr) (stand I), mature Norway spruce mixed with young beech (Fagus sylvatica) (5 yr) (stand II), and young Norway spruce (16 yr) (stand III). The latter two stands were converted or regenerated from the mature Norway spruce stand as former. The studied soils were characterized as having a very low pH value (2.9 – 3.5 in 0.01 M CaCl₂), a high total N content (1.06 – 1.94 %), a high metabolic quotient (qCO₂) (6.7 – 16.9 g CO₂ kg^–1 h^–1), a low microbial biomass N (1.1 – 3.3 % of total N, except LOf₁ at stand III), and a relatively high net N mineralization (175 – 1213 mg N kg^–1 in LOf₁ and Of₂, 4 weeks incubation). In the converted forest (stand II), C : N ratio and qCO₂ values in the LOf₁ layer decreased significantly, and base saturation and exchangeable Ca showed a somewhat increment in mineral soil. In the regenerated forest (stand III), the total N storage in the surface layers decreased by 30 %. The surface organic layers (LOf₁, Of₂) possessed a very high net N mineralization (1.5 – 3 times higher than those in other two stands), high microbial biomass (C, N), and high basal respiration and qCO₂ values. Meanwhile, in the Oh layer, the base saturation and the exchangeable Ca decreased. All studied substrates showed little net nitrification after the first period of incubation (2 weeks). In the later period of incubation (7 – 11 weeks), a considerable amount of NO₃‐N accumulated (20 – 100 % of total cumulative mineral N) in the soils from the two pure spruce stands (I, III). In contrast, there was almost no net NO₃‐N accumulation in the soils from the converted mixed stand (II) indicating that there was a difference in microorganisms in the two types of forest ecosystems. Soil microbial biomass N, mineral N, net N mineralization, L‐asparaginase, and L‐glutaminase were correlated and associated with forest management.