不同沙丘下梭梭(Haloxylon ammodendron)主根周围土壤特征的差异性研究

为探明沙漠建群种植物个体周围土壤养分和盐分空间分布及成因,对艾比湖湖区边缘三种类型沙丘下梭梭主根周围土壤含水量,电导率,全量养分和速效养分的变化进行了研究。结果表明:1固定性沙丘在表层(0~10 cm)处土壤含水量最小,流动性沙丘和半固定性沙丘在浅层(10~20 cm)处最小,以距离主根面3m处表现最为显著(P0.05)。2流动性沙丘和半固定性沙丘土壤有机质和全氮的结构性和空间自相关性均较弱,固定性沙丘养分(全量养分、速效养分)的结构性则较好。3三种沙丘土壤养分的空间分布不均,主要以条状和斑块状分布,整体上呈现出一定的集聚趋势,其中流动性沙丘和固定性沙丘集聚范围在0~2 m圈层,但纵向集聚范围中,流动性沙丘以浅层(10~20 cm),固定性沙丘以较深层(20~40cm)出现集聚,形成肥岛。4流动性沙丘土壤电导率对沙丘的影响较其他各特征因子占主导地位,半固定性沙丘和固定性沙丘养分因子占主导地位。     

侵蚀红壤腐殖酸组分特点及其对水稳性团聚体的影响

在华中地区采集不同侵蚀程度(轻度、中度、严重)的红壤,利用干湿筛法获得不同粒径的水稳性团聚体(0.25 mm)。通过测定不同粒径水稳性团聚体(0.25 mm)的腐殖酸组分(胡敏酸和富里酸)碳量,以及向不同侵蚀程度的各粒径团聚体(0.25 mm)中添加不同浓度(0.06、0.6 g L-1)的胡敏酸,分析侵蚀红壤腐殖酸组分特点及其对水稳性团聚体的影响。结果表明:随着侵蚀程度的增加,供试红壤和水稳性团聚体(0.25 mm)的腐殖酸组分含量减少;轻度和中度侵蚀红壤中,大粒径(4和2~4 mm)水稳性团聚体的胡敏酸碳量较小粒径(1~2、0.5~1和0.25~0.5 mm)的高;同种侵蚀程度下,除严重侵蚀红壤中2~4 mm团聚体的富里酸碳量与1~2 mm团聚体中的有显著差异外,不同粒径团聚体中富里酸碳量差别不大。3种侵蚀程度红壤的胡富比总体上小于1,其中中度侵蚀红壤和各粒径水稳性团聚体的胡富比均大于其他两种侵蚀程度的。腐殖酸组分与水稳性团聚体(0.25 mm)含量呈极显著正相关,与胡敏酸碳量的相关系数最大(r=0.85**,n=19)。添加不同浓度(0.06和0.6 g L-1)胡敏酸后,3种侵蚀程度红壤各粒径水稳性团聚体(0.25 mm)的含量均增加,且小粒径团聚体(1~2、0.5~1和0.25~0.5 mm)的增加量要高于大团聚体(2~4、4 mm)的。     

RETRACTED ARTICLE: Distribution of carbon,nitrogen, carbohydrate and calcium carbonate in aggregates of histosols in Shahrekord,Iran

Soil organic matter and its components play a key role in the stabilization of soil aggregates. This study aimed to investigate the distribution of organic carbon (OC), total nitrogen (TN), hot-water extractable (HWE) and dilute acid extractable (DAE) carbohydrates and CaCO₃ in water-stable aggregates in histosols of Shahrekord, Iran. Additionally, correlations between aggregate stability (mean weight diameter (MWD) values) and mentioned characters were also examined. Results showed that at all depths in all 18 profiles, larger aggregates contained more OC, TN and carbohydrate content than the smaller aggregates, whilst CaCO₃ had the opposite trend. OC, TN and carbohydrate fractions followed a consistent similar trend by aggregate size. The positive correlation between OC and TN within the aggregates was considerable. OC, TN, carbohydrate fractions and MWD significantly (P < 0.01) decreased with depth. Average concentration of CaCO₃ was almost the same in aggregates <4 mm at all depths. We observed very low values of ratios HWE:OC and DAE:OC in the study site. OC, TN and carbohydrate fractions each gave highly or very highly significant correlations with aggregate stability. We obtained significant, but weak negative correlation of CaCO₃ with aggregate stability (P = 0.05; r = ?0.23), implying that CaCO₃ is a disaggregating agent in these histosols.     

Water-stable aggregates, glomalin-related soil protein, and carbohydrates in a chronosequence of sandy hydromorphic soils

The conversion of pasture to cropland leads to a decline of aggregation in topsoils and to a decrease of aggregate-binding agents such as carbohydrates and glomalin-related soil protein (GRSP). Till now, studies on soil aggregation focused either on carbohydrates or on GRSP as a binding agent in aggregates. In this study we analyse the development of the relationship between carbohydrates, GRSP, TOC and aggregate-stability following land-use change. Furthermore, we discuss the contents of carbohydrates, GRSP and TOC in each of the aggregate fractions. For these purposes, a chronosequence of sites, which were converted from pasture to cropland at different periods in history, was established. To get further insight into the impact of different types of land-use, also soils under forest, either afforested or permanent, were studied. The mean-weight diameter (MWD) of water-stable aggregates, the carbohydrate, and the GRSP content were determined in 49 soils. It was found that the MWD of the water-stable aggregates decreased monoexponentially (R² = 0.66) by 66% during the first 46 years after conversion of the soils from pasture to cropland. During the same period, the carbohydrate content decreased very rapidly after the land use change by 64% and the GRSP content decreased more slowly by 57%. The MWD of the forest soils were in the same range as those of the permanent pasture soils although they exhibit significantly higher TOC contents, which indicate that other stabilization mechanisms are dominant in forest soils, less important in the chronosequence soils. TOC, carbohydrates and the GRSP contents were sigmoidally correlated with the MWD. Among the four water-stable aggregate fractions TOC and carbohydrates exhibited high contents in the macroaggregates and were less present in the microaggregates. GRSP, in contrast, was more equally distributed among the four water-stable aggregate fractions.     

Water-stable aggregates and associated organic matter in forest,savanna, and cropland soils of a seasonally dry tropical region,India

The study was undertaken to quantify the distribution of soil in different size fractions of water-stable aggregates, and organic C, total N, and total P associated with these aggregates, along a gradient of forest-savanna-cropland in the Indian dry tropics. The effect of residue (wheat straw) amendment under dryland cultivation was also investigated. Proportions of macroaggregates (>0.3 mm) were highest in the forest and lowest in the cropland soil and ranged from 58–66% in forest, to 55% in savanna and 25–36% in cropland. In contrast, microaggregates (<0.3 mm) were highest in cropland (64–75%), followed by savanna (45%), and lowest in forest soil (34–42%). Organic C, total N, and total P associated with the macroaggregates ranged from 6.52–29.56, to 0.62–2.44 and 0.06–0.15 g kg^-1 soil, respectively, while the respective values in microaggregates were 4.99–22.11, 0.42–2.01, and 0.07–0.19 g kg^-1 soil. This study indicates that land-use changes (conversion of forest into savanna and cropland) reduce the organic matter input to the soil and the proportion of macroaggregates. The application of wheat straw did not significantly influence the organic C and total N levels (P>0.05) in the short term, although the proportion of macroaggregates increased, indicating an improvement in soil structure. Thus soil degradation after conversion of natural systems to cropland can be arrested up to some extent by residue input to the soil.     

PAM对黄土高原主要土壤类型水稳性团聚体的改良效果及机理研究

通过室内土柱培养,研究PAM对黑垆土、黄绵土、风沙土水稳性团聚体的改良效果,并探讨其作用机理和合理的施用浓度.结果表明,在浓度为0.05%～0.4%,PAM均可促进3种土壤＞0.25 mm水稳性团聚体的形成,并有效降低3种土壤团聚体分形维数,改善土壤结构;方差分析表明,PAM改良3种土壤结构的机理是一致的,将＜1mm的水稳性团聚体聚合为更大粒径的水稳性团聚体,使＞1mm的水稳性团聚体含量增加.PAM改良黑垆土、黄绵土和风沙土土壤水稳性团聚体达到显著水平时的浓度也不相同,其适宜浓度分别为0.2%～0.4%,0.05%,0.05%.3种土壤的黏粒含量和有机质含量的差异,可能是影响PAM对不同土壤的水稳性团聚体的改良效果差异的主要原因.     

中国黄土高原区轮耕对土壤团聚体、有机碳氮含量的影响

In rain-fed semi-arid agroecosystems, continuous conventional tillage can cause serious problems in soil quality and crop production, whereas rotational tillage (no-tillage and subsoiling) could decrease soil bulk density, and increase soil aggregates and organic carbon in the 0-40 cm soil layer. A 3-year field study was conducted to determine the effect of tillage practices on soil organic carbon (SOC), total nitrogen (TN), water-stable aggregate size distribution and aggregate C and N sequestration from 0 to 40 cm soil in semi-arid areas of southern Ningxia. Three tillage treatments were tested: no-tillage in year 1, subsoiling in year 2, and no-tillage in year 3 (NT-ST-NT); subsoiling in year 1, no-tillage in year 2, and subsoiling in year 3 (ST-NT-ST); and conventional tillage over years 1-3 (CT). Mean values of soil bulk density in 0-40 cm under NT-ST-NT and ST-NT-ST were significantly decreased by 3.3% and 6.5%, respectively, compared with CT, while soil total porosity was greatly improved. Rotational tillage increased SOC, TN, and water-stable aggregates in the 0-40 cm soil, with the greatest effect under ST-NT-ST. In 0-20 and 20-40 cm soils, the tillage effect was confined to the 2-0.25 mm size fraction of soil aggregates, and rotational tillage treatments obtained significantly higher SOC and TN contents than conventional tillage. No significant differences were detected in SOC and TN contents in the >2 mm and <0.25 mm aggregates among all treatments. In conclusion, rotational tillage practices could significantly increase SOC and TN levels, due to a fundamental change in soil structure, and maintain agroecosystem sustainability in the Loess Plateau area of China.     

长期施肥对华北农田褐土团聚体微结构与稳定性的影响

为定量分析不同施肥措施对华北农田褐土微观结构及稳定性的影响,该研究依托长期定位施肥试验,集成同步辐射显微CT（SR-μCT）与图像处理技术对不施肥（CK）、氮磷钾肥（NPK）和有机、无机配施（OF）三种处理土壤团聚体微结构及其稳定性进行定量分析,结果表明：经过26 a不同施肥处理,研究区土壤孔隙微结构与稳定性产生了实质性变化,其中长期OF处理土壤孔隙度、大孔隙率、狭长孔隙率、平均孔隙直径、平均弯曲度、孔喉平均表面积及平均质量直径等指标较CK处理分别提升了23.84%、145.71%、21.43%、37.16%、21.3%、51.12%和59.26%,表明长期OF处理显著改善了研究区土壤微结构,提升了团聚体稳定性。长期NPK处理与CK处理土壤团聚体在微结构特征与稳定性方面相似,但大孔隙（等效直径≥500 μm）率均显著低于OF处理（P<0.05）。研究结果可为农业土壤质量评价与保护提供支撑。     

菜地土壤有机碳分级以及总量变化的动态特征研究

Fertilisers significantly affect crop production and crop biomass inputs to soil organic carbon（SOC）. However, the long-term effects of fertilisers on C associated with aggregates are not yet fully understood. Based on soil aggregate and SOC fractionation analysis, this study investigated the long-term effects of organic manure and inorganic fertilisers on the accumulation and change in SOC and its fractions, including the C concentrations of free light fraction, intra-aggregate particulate organic matter（POM） and intra-aggregate mineral-associated organic matter（MOM）. Long-term manure applications improved SOC and increased the concentrations of some C fractions. Manure also accelerated the decomposition of coarse POM（cPOM） into fine POM（fPOM） and facilitated the transformation of fPOM encrustation into intra-microaggregate POM within macroaggregates. However, the application of inorganic fertilisers was detrimental to the formation of fPOM and to the subsequent encrustation of fPOM with clay particles, thus inhibiting the formation of stable microaggregates within macroaggregates. No significant differences were observed among the inorganic fertiliser treatments in terms of C concentrations of MOM, intra-microaggregate MOM within macroaggregate（imMMOM） and intra-microaggregate MOM（imMOM）. However, the long-term application of manure resulted in large increases in C concentrations of MOM（36.35%）, imMMOM（456.31%） and imMOM（19.33%） compared with control treatment.     

蒋家沟泥石流源区土壤团聚体微结构与结构性

 云南东川蒋家沟泥石流源区的土壤是团聚体结构性很强的特殊土壤,孔隙比高,液限低,并有强烈的分散性,在环境扫描电镜下的微观结构表明:原状土壤团聚体具有3种孔隙类型,沿着孔隙溶蚀现象明显,骨架颗粒之间普遍存在架空结构,胶结物联结强度较弱。通过对土壤团聚体在原状、饱和、重塑3种状态下进行室内压缩试验,并引入综合结构势,分析土壤团聚体的结构性。结构性参数曲线在加载初期下降显著,在加载后期则变得十分平缓,表明蒋家沟泥石流源区土壤团聚体具有较强的结构性,容易发生结构失稳。因此,微观结构特性与结构性对土壤团聚体的稳定性有重要的作用。     

高黎贡山土壤腐殖质特性与团聚体数量特征研究

采用野外调查与室内分析结合的方法,研究高黎贡山土壤腐殖质特性与团聚体数量特征,对进一步了解高黎贡山生态系统中土壤特征,降低土壤侵蚀,减少水土流失提供科学依据。结果表明:土壤腐殖质的组成具有明显地带性特征,有机质、腐殖酸含量、胡/富(HA/FA)随海拔高度的降低呈先上升后下降的趋势,A1层胡敏酸(HA)、富里酸(FA)含量分布规律为暗棕壤棕壤棕色针叶林土亚高山草甸土黄棕壤黄壤黄红壤。A2层腐殖酸、FA变化趋势为暗棕壤棕壤棕色针叶林土黄棕壤黄壤亚高山草甸土黄红壤。A1层HA、FA分子复杂程度、化学稳定性比A2层强。1～0.5mm和0.25mm粒径的团聚体含量占绝大多数,约占60%～70%。随着海拔高度的降低,粗粒减少,细粒增多。土壤团聚体服从对数正态分布,其几何平均直径与几何标准差、土壤可蚀性K值之间存在负相关关系,土壤可蚀性K值与几何标准差存在正相关关系,同时土壤也具有一定的分形特性。其中亚高山草甸土几何平均直径(Dg)、平均重量直径(MWD)值最大,几何标准差(δg)、可蚀性K值、分形维数(CFD)值最小,土壤结构稳定性和抗蚀能力相对较强。胡敏酸含量是影响土壤可蚀性的重要因素。     

Soil organic carbon and nitrogen in aggregates in response to over seven decades of farmyard manure application

The study aimed to evaluate the effects of long-term fertilisation on soil aggregation and the associated changes in soil organic carbon (SOC) and nitrogen (N) pools in aggregates. The combined application of mineral fertiliser and manure improved soil aggregation, SOC and N content in aggregates, compared to manure or mineral fertiliser alone, and thus proved to be a suitable fertilisation strategy to increase C sequestration in agroecosystems.     

土壤团聚体氧化亚氮排放潜势与微生物学机制

氧化亚氮（N2O）是主要温室气体之一,土壤是N2O的重要排放源,其排放主要受N2O产生和还原的功能微生物影响。土壤团聚体是由原生颗粒（砂、粉、黏粒）、胶结物质和孔隙组成的土壤基本结构单元。土壤不同粒径团聚体之间因基质和孔隙差异形成特殊独立的微生境被视为N2O的生物化学反应器。在不同的微生境中,N2O产生和还原的功能微生物分布不同,因而土壤不同粒径团聚体N2O排放可能存在差异。目前在不同生态系统土壤全土N2O排放特征的报道较多,而对于不同粒径土壤团聚体N2O排放相对贡献尚不清楚、功能微生物分布还未知、N2O产生和还原热区尚未明确。本文综述了近年来国内外关于土壤团聚体对N2O产生和排放机制的研究,总结了土壤团聚体性状特征对N2O产生和还原的影响,阐述了不同粒径土壤团聚体对N2O排放影响的微生物学机制,进一步明确了今后需加强土壤团聚体N2O产生和还原的热区、环境因子阈值范围的确定、系列功能基因（酶）整体性的研究,以期为N2O模拟排放模型优化提供参考,为土壤N2O减排提供理论依据。     

退化红壤植被恢复中表层土壤微团聚体及其有机碳的分布变化

采用超声波分散分离提取土壤微团聚体 ,通过测定有机碳含量、分析碳稳定性同位素 ,研究了退化红壤在植被恢复下土壤微团聚体粒组分布与有机碳分布 .结果表明 ,植被恢复尤其是豆科 -禾本科植物轮作较快地增加了土壤有机碳储存 ,这种碳存储表现为 2～ 0 .2 5mm团聚体的建成 ,并对微团聚体有机碳的稳定性同位素组成分异产生影响 .本文揭示了我国广泛实施的区域土壤治理和植被恢复措施促进了土壤碳截存 ,可以认为显著地贡献于陆地系统对大气CO2 的汇作用     

土壤健康与农业绿色发展: 机遇与对策

  目的  为探明有机物料还田配合优化施氮对石灰性潮土土壤有机碳（SOC）及其活性组分、土壤团聚体的形成与稳定性的影响。  方法  依托长期定位试验,设置农民习惯施氮（CF_N）、优化施氮（OF_N）、秸秆还田 + 优化施氮（S_N）和生物炭 + 优化施氮（BC_N）四个处理开展土壤有机碳固定效果与机制的研究。  结果  四种施肥方式下,BC_N处理对土壤有机碳的提升效果最明显,达到18.68 g kg⁻¹,其次依次为S_N、CF_N和OF_N处理。与CF_N处理相比,有机物料还田配合优化施氮能够显著增加土壤微生物量碳（MBC）、可溶性有机碳（DOC）、颗粒态有机碳（POC）和易氧化有机碳（EOC）的含量,增幅分别为128.26%、96.62%、219.72%和45.42%;同时,> 0.25 mm团聚体的比例与土壤团聚体平均重量直径（MWD）显著提高,S_N与BC_N较CF_N处理> 0.25 mm团聚体的比例分别增加132.44%和91.45%,MWD值分别增加89.79%和66.87%。这主要得益于土壤交换性Ca^{2 +} 、Mg^{2 +} 、K ⁺ 和Na ⁺ ,以及铁铝氧化物含量的改善对大团聚体形成与稳定的驱动作用。OF_N处理较CF_N处理显著减少了氮肥投入量（261 vs. 480 kg N hm⁻² yr⁻¹）,但所测定的各指标均未表现出显著差异。  结论  尽管长期（12年）秸秆与秸秆生物炭等碳量还田配合优化施氮提高土壤有机碳含量、改善土壤团聚体结构的效果存在差异,但均显著优于单施氮肥处理。研究结果可为华北平原石灰性潮土农田碳氮协同调控策略促进土壤健康提供理论支撑。     

Rapid and sensitive determination of microbial activity in soils and in soil aggregates by dimethylsulfoxide reduction

Summary Based on the reduction of dimethylusulfoxide (DMSO) to dimethylsulfide (DMS) by microorganisms, a simple, rapid, sensitive and inexpensive method for the determination of microbial activity in soil samples was developed. When DMSO was added to samples, DMS appeared immediately in the gas phase, which was quantitatively analyzed by gas chromatography. The DMS liberation rate was constant for several hours. The reaction immediately starts and its linearity indicate that neither the physiological state nor the number of organisms were changed by the assay. DMSO reduction is widespread among microorganisms; out of 144 strains tested (both fungi and bacteria) only 5 were unable to carry out this reaction. The reaction in soil samples was strongly inhibited by toluene, cyanide, azide, or by fumigation, but was considerably stimulated by glucose. These findings demonstrate that the reaction was due to the activity of microorganisms. The DMSO reduction in different soil samples was significantly correlated with arginine ammonification and heat output (r>0.9). A good correlation was observed with the organic-matter content (r = 0.74), but not with microbial numbers, clay content, or the pH of the soil. Standard deviations of less than 10% were routinely found. Furthermore, the method is sufficiently sensitive to allow measurements of activity in very small samples (< 0.1 g). For example, a microbial activity profile can be established for a single soil aggregate, revealing marked differences in activity on the outside and in the interior.     

不同改良剂对黄绵土水稳性团聚体的改良效果及其机制

通过室内土柱培养,采用聚丙烯酰胺(Polyacrylamide,PAM)、沃特保水剂、β-环糊精、腐殖酸等4种土壤结构改良剂对黄绵土水稳性团聚体进行改良。结果表明:4种改良剂均可促进>0.25 mm水稳性团聚体的形成,在浓度0.05%～0.40%范围内,其改良效果表现为PAM>β-环糊精>沃特保水剂>腐殖酸,且黄绵土团聚体分形维数显著降低,尤以PAM改良效果最明显;在低浓度条件下,4种改良剂均可有效地降低土壤密度;土壤粒径分布表明,PAM改良黄绵土水稳性团聚体的机制是使<1 mm粒径的团聚体团聚为更大的团聚体,尤其是团聚为>5 mm的团聚体,PAM在4种改良剂中对黄绵土改良效果最好。阐明不同改良剂对黄绵土水稳性团聚体的改良效果及机制,可为合理利用改良剂改良土壤结构提供理论依据。     

南方红壤丘陵区侵蚀沟道内土壤团聚体及有机碳特征

为了更好地揭示特殊地形下水蚀过程对土壤结构和有机碳含量分配的影响,选取典型南方红壤丘陵区—青原山小流域为研究区,采用核素¹³⁷Cs示踪技术研究小流域侵蚀沟道内水土流失现状,分析了沟道侵蚀对土壤团聚体稳定性及有机碳含量的影响。结果表明:侵蚀沟道的坡顶处¹³⁷Cs含量最高,且高于背景值,属于沉积区,而坡上、坡脚属于中度侵蚀,坡中属于轻度侵蚀;侵蚀沟道顺坡而下侵蚀过程依次表现为绝对沉积、绝对侵蚀、相对沉积和绝对侵蚀,其中植被和地形因子是主导因素;沉积区相比于侵蚀区平均质量直径(Mean Weight Diameter,MWD)和大团聚体含量(粒径≥0.25 mm)更高,侵蚀区中相对沉积的坡中有着更稳定的土壤团粒结构;沉积区各个粒径的土壤团聚体有机碳含量均高于侵蚀区,侵蚀区的土壤团聚体有机碳更趋向于均匀分配,土壤理化性质的空间差异也会影响土壤团聚体有机碳含量。侵蚀沟道中土壤侵蚀模式与传统坡面并不一致,土壤结构及相关碳组分主要受地形和植被支配下的土壤侵蚀程度影响。     

不同土壤管理措施下塿土团聚体的大小分布及其稳定性

土壤团聚体是土壤的重要组成部分,其大小分布影响土壤的功能。本文利用22年土长期定位试验,研究不同土壤管理措施和不同施肥对土壤机械稳定性和水稳性团聚体的分布及其稳定性的影响。土壤管理措施包括裸地休闲、 撂荒和小麦/玉米轮作体系,其中小麦/玉米轮作体系中有9种施肥处理,分别为不施肥（CK）,化肥氮（N）、 磷（P）和钾（K）不同配施5个处理（N、 NP、 NK、 PK、 NPK）,秸秆还田与化肥配合（SNPK）,有机肥与化肥配施2个处理（M1NPK、 M2NPK）。结果表明,不同管理措施显著影响表层（010 cm）和亚表层（1020 cm）土壤的机械稳定性和水稳性团聚体的分布。与作物体系比较,长期休闲可显著增加机械稳定性微团聚体（0.25 mm）的含量,对水稳性团聚体的含量和分布没有显著影响。而长期撂荒显著增加了大于2 mm 的团聚体含量及团聚体的稳定性。长期不同施肥显著影响 030 cm 土层的机械稳定性和水稳性团聚体的分布,总趋势为施肥比不施肥处理降低了1 mm的团聚体含量,增加了0.25~1 mm的团聚体含量,但对土壤团聚体的稳定性没有显著影响。因此,土撂荒22年后显著增加了土壤团聚体的稳定性,而种植作物和不同施肥处理对土壤团聚体的稳定性影响甚微。     

黄土高原不同植物群落土壤团聚体中有机碳和酶活性研究

以黄土高原延河流域森林区3种典型植物群落为研究对象,研究了3种植物群落土壤团聚体中有机碳的含量、组分及土壤酶活性,分析了有机碳与酶活性的关系。结果表明:(1)3种植物群落,土壤团聚体各种形态有机碳和酶活性均表现为0~10 cm土层含量高于10~20 cm土层,辽东栎群落0~10 cm土层土壤多酚氧化酶活性却低于10~20 cm土层。(2)土壤团聚体有机碳含量在植物群落间表现为:辽东栎群落人工刺槐群落狼牙刺群落,酶活性在植被群落间的高低表现则不一致。土壤有机碳含量和酶活性在团聚体间均表现为随团聚体粒级的增大而增大,或先增大再减小的趋势。(3)蔗糖酶、纤维素酶以及β-D葡糖苷酶活性与各种形态有机碳均呈显著的正相关关系,多酚氧化酶和过氧化物酶与有机碳含量相关性不显著。(4)辽东栎群落和狼牙刺群落土壤团聚体蔗糖酶、纤维素酶、以及β-D葡糖苷酶活性在团聚体中表现为:|0.25 mm团聚体||2~0.25 mm团聚体||5~2 mm团聚体||5 mm团聚体|,其多酚氧化酶和过氧化物酶以及人工刺槐群落各种土壤酶活性均表现为2~0.25 mm粒级团聚体中最大。(5)β-D葡糖苷酶活性增大,能促进土壤各种有机碳含量增加;土壤蔗糖酶活性和β-D葡糖苷酶活性的提高有助于土壤活性有机碳含量增加;土壤多酚氧化酶活性的增大,有利于土壤腐殖质碳的积累。