北京山区主要人工林枯落物水文效应

为探究北京山区主要人工林枯落物水文效应,以北京市怀柔区汤河口镇庄户沟小流域油松、刺槐、侧柏3种林分为研究对象,利用枯落物现存量样地调查、浸泡实验和抗冲槽法,建立枯落物持水量、吸水速率和浸水时间相关关系,定量研究枯落物层水文效应,结果表明:1)3种林分枯落物现存量和总厚度表现为油松最大,分别为6.37t/hm2和4.0c...     

Migration of nickel and copper in forest litters under the effect of simulated rainfall

The leaching of Ni and Cu from undisturbed forest litter layers under the impact of simulated natural and contaminated rainfalls was studied under laboratory conditions. Samples were collected in the vicinity of a copper-nickel smelter on the Kola Peninsula, northwestern Russia. Both Ni and Cu were significantly accumulated in the natural (uncontaminated) forest litter; the contaminated litter also uptook Cu and, to a lesser extent, Ni. The metals migrated through the forest litter as organometal complexes, mainly with acid-soluble components. In the contaminated forest litter, the migration of Ni was also affected by pH.     

The influence of heating on organic matter of forest litters and soils under experimental conditions

The specific features of changes in the content and mobility of organic matter in litters and cryogenic soils under heating were revealed. The thermal stability of the organic matter and litters is different. In the soils, the maximal loss of matter was recorded at a temperature of 300°C. In the litters, the maximal losses were found at 300, 400 and 550°C and depended inversely on the carbon content in them. The heating to 200°C caused insignificant changes in the mass of the litters and soils but increased the content of the water-soluble fraction of organic matter and the concentration of the water-soluble mineral nitrogen forms.     

The optical properties in alkali-soluble fractions extracted from newly shed litters in a subalpine forest

Journal of Soils and Sediments - Humification of plant detritus is an important pathway for soil organic matter formation. The long-standing studies considered that humification proceeds at very...     

Chemical quality impacts of tropical forest tree leaf litters on the growth and fecundity of soil Collembola

The growth performances of a soil microarthropod, Cyphoderus javanus Börner (Collembola: Hexapoda), were tested in microcosms on leaf litter of different tropical forest trees to compare their nutritional quality to detritivores. The macronutrient profile was more or less similar between the litter types, but the quantities of non-nutrients like polyphenols, tannins and lignins were notably higher in the litter of Acacia auriculiformis and Shorea robusta trees than in the litter of Cassia siamea and Dalbergia sissoo trees. A choice experiment showed persistently higher colonisation of Collembola on litter of Cassia and Dalbergia, which differed significantly from a trend of lower occurrence in Acacia and Shorea. The nutritional benefit of the litter types was compared by measuring levels of tissue carbohydrates, proteins and lipids in C. javanus. Analysis of data by t test showed that animals reared on Cassia and Dalbergia litters contained statistically significant higher concentrations of tissue carbohydrates and proteins than those fed on Acacia. But the differences with the animals fed on Shorea were not significant. In contrast, C. javanus registered significantly low levels of tissue lipids in Cassia and Dalbergia litters when compared to animals reared on Acacia and Shorea litters. The 2-way RM-ANOVA test revealed highly significant main effect of time intervals for tissue carbohydrates and proteins and highly significant main effect of litter types for tissue lipids. Benefits derived from litter quality on growth were seen from enhanced fecundity and higher rate of moulting of C. javanus reared on Dalbergia followed by Cassia, Acacia and Shorea in descending order. The higher reproductive rate on Dalbergia and Cassia probably resulted in decreased level of tissue lipids in animals. Growth parameters, namely tissue nutrients, fecundity and moulting were influenced by the chemical constituents of different litter types, and these qualities are potential indicators of the nutritional quality of litter to detritivores, and the ecological suitability of tree species for enhancing the biological activity in soil system.     

Geographical and genetic aspects of the Red Book of Russian Soils

An overview of soil objects from different regions and of different categories that are listed in the Red Book of Russian Soils is presented. Most of these objects are soils that support the existence of rare plant and animal species; the number of reference and zonal soils is almost equal and sufficient attention has been paid to soils that are used for scientific and training purposes. Semidesert soils are represented best; less focus is given to steppe soils; podzols and podzolic soils of Siberia have been given fairly limited consideration. To describe Russian soils in their real diversity makes it necessary to include new reference (cryozems and svetlozems) and rare (granuzem and cryoaridic) soils in the Red Book.     

An improved method for purifying genomic DNA from forest leaf litters and soil suitable for PCR

Background, aim and scope  An improving knowledge of bacterial community within natural environments including forest soils and leaf litters requires extraction of nucleic acids directly from environmental samples since molecular approaches provide less biased access to a larger portion of uncultivable microorganisms. However, when DNA was extracted successfully from these samples, it might still have been difficult to apply it as a template for polymerase chain reaction (PCR) amplifications due to the effect of PCR inhibitors. Various compounds from plant tissues including polysaccharides, phenolic compounds and especially humic acids can inhibit PCR amplification. Some of these inhibitors could inhibit PCR amplification by chelating the Mg²⁺ (cofactor for Taq polymerase), or by binding to target DNA, and PCR amplification would consequently be interfered with. Therefore, eliminating the effects of these PCR inhibitors is one of the most important steps for PCR-based molecular techniques. Four different methods were assessed in this study to purify the genomic DNA extracted from F, L layer leaf litters and forest soil in an exotic pine plantation of southeast Queensland, Australia. Materials and methods  Three samples including two leaf litters and one forest soil were collected with a core (25 × 40 cm) from a 22-year-old slash pine plantation in southeast Queensland, Australia. The DNA fragments were extracted directly using the Ultra Clean™ Mega Prep Soil DNA kit (Mo Bio Labs, Solana Beach, CA). Then, four different purification methods were applied and compared to purify the DNA for PCR amplification, which include PVPP, Sephadex ^TM spin column, low-melting agarose gel and a new modified gel purification method. The purified DNA from these four purification methods was detected by agarose gel electrophoresis, and the purity and usefulness of DNA samples were ultimately determined by successful PCR amplifications. Results and discussion  The DNA was extracted from each sample using the Ultra Clean™ Mega Prep Soil DNA kit, and the DNA eluents were dark in colour and sometimes formed compact aggregates. Subsequently, PCR amplification from such samples failed, although a series of dilutions had been made from neat to 1:10³. The DNA purification step could not, therefore, be avoided. It was observed that both the colour of eluent and the DNA concentration decreased gradually after elution. Considering the difficulties of removing PCR inhibitors and the possibility of high DNA losses, 50–200 μl of sample DNA was used for purification. Four DNA purification methods (the PVPP spin column, Sephadex™ spin column, low-melting agarose gel and the modified gel purification method) were applied and compared on leaf litter and soil samples. The DNA purified by the modified gel purification method provided the best PCR products for 16S rRNA gene amplification, but the other methods, PVPP, Sephadex™ spin column and low-melting agarose gel, produced very weak or no products. Thus, in this study, DNA fragments which were purified by the modified gel purification method were amplified efficiently. This may be attributed to running the low-melting agrose gel for a longer time, which could remove substantial humic substances and also some other compounds from the samples and, thus, prevent them from being involved in PCR amplification. Conclusions  A new modified gel purification method which can improve DNA purification and PCR amplification of environmental DNA is first introduced in this study. Comparing PVPP, Sephadex ™ spin column, low-melting agarose gel and modified gel purification method for the effect of DNA purification, the modified gel purification method is more successful in removing the PCR amplification inhibitors and obtaining the highly purified PCR amplifiable high-molecular-weight DNA. The method described here is cheap, fast and easy to operate. It suggests in this study that the method containing less and easier following steps should be widely used to relieve the heavy working load of molecular-biological researchers. Recommendations and perspectives  This study introduces a new modified DNA purification method, and it is found that this modified gel purification method is effective in removing the PCR inhibitors and obtains highly purified DNA from leaf litters for PCR amplification. The modified gel purification method may have wider applications, although it was only assessed on leaf litter and soil samples. The effect of the modified gel purification method on the DNA purification would need to be further investigated on a variety of samples which suffered from PCR inhibitors, such as clinical samples, plant tissues and environmental samples.     

飞播马尾松林不同林下植被类型枯落物及土壤水文效应

为探明飞播马尾松林不同林下植被类型对枯落物及土壤水文效应的影响,按林下植被优势(分芒萁类、禾本类及灌木类3种类型)设置典型样地,对其枯落物持水性能及土壤蓄水能力进行比较分析.结果表明:3种类型的枯落物现存总蓄积量为0.65 ～3.57t/hm2;其中,灌木类总蓄积量＞芒萁类＞禾本类.3种类型枯落物自然含水率、最大持水率、最大拦蓄率及有效拦蓄率范围分别为15.50％～29.74％、167.70％～218.25％、139.00％ ～199.66％和113.85％ ～167.39％;枯落物自然含水量、最大持水量、最大拦蓄量及有效拦蓄量均表现为灌木类＞芒萁类＞禾本类,除半分解层自然含水量以外,其他持水量指标均表现为灌木类显著高于其他2种类型.0 ～ 20 cm土层的饱和蓄水量、非毛管持水总量以及毛管持水总量均以芒萁类最高,分别为865.95、138.96和726.99 t/hm2;其中,芒萁类在0～20 cm土层,非毛管持水总量显著高于其他2种类型,而0～ 10 cm土层饱和蓄水量显著高于禾本类.综合分析表明:灌木类枯落物的水文效应显著高于禾本类和芒萁类,而芒萁类土壤层水文效应明显优于灌木类和禾本类,这是由于土壤层饱和蓄水量及有效蓄水量分别占林地表层(枯落物层和0 ～ 20 cm土壤层)的99％和94％以上,总体上芒萁类林地表层水文效应明显优于灌木类和禾本类.     

北京九龙山8种林分的枯落物及土壤水源涵养功能

为了阐明森林植被的水源涵养功能,对北京九龙山油松纯林、华北落叶松纯林、侧柏纯林、樟子松纯林、栓皮栎纯林、五角枫纯林、油松日本落叶松混交林、油松华北落叶松混交林等8种林分类型的枯落物和土壤持水性能进行研究.结果表明：各林分枯落物总储量变化范围为8.87 ～47.87 t/hm^2,其中未分解层储量大于半分解层储量;综合枯落物未分解层和半分解层最大持水量和有效拦蓄量的变化规律来看,油松纯林最大持水量最大（36.46t/hm^2）,其次为华北落叶松纯林（36.06 t/hm^2）,侧柏纯林最小（11.83 t/hm^2）;油松日本落叶松混交林的有效拦蓄量最大（23.51 t/hm^2）,其次为樟子松纯林（19.85 t/hm^2）,侧柏纯林最小（9.53t/hm^2）;综合考虑不同林分枯落物与土壤涵养水源能力发现,华北落叶松纯林和油松华北落叶松混交林具有良好的水源涵养功能;不同层次枯落物持水量、吸水速率与浸水时间均存在较好的函数关系;8种林分土壤容重均值在0.89～ 1.41 g/cm3之间变动,总孔隙度在39.43％ ～54.23％之间变动;林地土壤的入渗速率与人渗时间通过回归分析得出,二者呈幂函数关系,且R2值均在0.90以上.     

Effect of individual trees on the pH and the content of heavy metals in forest litters upon industrial contamination

The influence of individual spruce and birch trees on the distribution of heavy metals (Cu, Pb, Cd, and Zn) and hydrogen ions in the forest litter is considered in a territory subjected to long-term industrial pollution by emissions of the Ural copper smelter (town of Revda, Sverdlovsk oblast, southern taiga). In the background territory, the content of the elements regularly decreases from the tree trunks to the canopy gaps, whereas, in the contaminated territory, this relationship is either not traced at all (for the metal concentrations) or more weakly pronounced (for the metal reserves and pH values). The influence of trees on the spatial distribution of metals in the litter is specific for various elements and differs in coniferous and deciduous biotopes.     

陕北黄土丘陵区牧草枯落物对针叶纯林土壤极化的修复效应

针对陕北半湿润黄土丘陵区的侧柏、油松和落叶松等针叶纯林,在前期关于土壤极化研究的基础上,通过采集林地腐殖质层土壤与7种不同牧草枯落物进行混合分解培养,研究不同牧草枯落物对针叶纯林土壤的修复效应,以此作为选择适宜修复牧草种的依据。结果表明：（1）针对侧柏纯林土壤,苜蓿等7种牧草对于速效钾含量,苜蓿、胡枝子、沙打旺、小冠花和草木樨对于蛋白酶活性的负向极化具有显著缓减作用。（2）针对油松纯林土壤,7种牧草对于碱解氮含量,毛苕子、苜蓿和草木樨对于有效磷含量,苜蓿对于蔗糖酶活性的负向极化均有显著缓减作用。（3）针对落叶松纯林土壤,胡枝子和红豆草对于碱解氮含量,苜蓿、红豆草、小冠花和毛苕子对于有效磷含量,除苜蓿和毛苕子外的其他牧草对于有机质含量,苜蓿以外其他牧草对于磷酸酶活性的负向极化均具有显著缓减作用。（4）综合主成分分析表明,对侧柏纯林土壤综合修复效果较好的依次是沙打旺、小冠花、胡枝子和毛苕子;对于油松纯林土壤综合修复效果较好的依次是苜蓿、小冠花和草木樨;对于落叶松纯林土壤综合修复效果较好的依次是苜蓿、草木樨和红豆草。     

Features of forest litters in conjunction with ground cover in the forest ecosystems of Moscow oblast (based on the example of the Chashnikovo Educational-Experimental Soil-Ecological Center)

The stocks and structure of forest litters in a typical biogeocenosis in conjunction with the ecological and botanical characteristics of the soil layer have been studied, based on the example of the Chashnikovo Educational-Experimental Soil-Ecological Center, Moscow State University. The most informative characteristics of the soil layer include species diversity, the relative share of oligotrophic boreal and nitrophilous species, and the soil fertility index determined by the Ramensky ecological scale [20]. The total litter stock varies from 1500 to 6000 g/m² in coniferous forests and from 70 to 700 g/m² in small-leaved forests. The highest difference in stocks between the F and L horizons has been established for vegetation microcommunities with the maximum species diversity and highest share of nitrophils. The increase in the portion of welldecomposed fractions in the L piedmont from 5–7 to 27.6% leads to growth in the soil fertility index from 5–6 to 12–13.     

雪被斑块对高山森林凋落叶腐殖化过程中胡敏酸和富里酸累积的影响

高山森林凋落叶腐殖化过程中胡敏酸(Humic acid,HA)、富里酸(Fulvic acid,FA)等腐殖物质的累积是土壤形成和碳吸存的重要途径,并可能受到冬季不同厚度雪被斑块的影响,但一直缺乏必要关注。本文采用凋落物网袋法,于2012/2013年冬季研究了川西高山森林天然形成的不同厚度雪被斑块(厚雪被、中雪被、薄雪被和无雪被)下优势树种岷江冷杉(Abies faxoniana)、方枝柏(Sabina saltuaria)、四川红杉(Larix mastersiana)、红桦(Betula albo-sinensis)、康定柳(Salix paraplesia)和高山杜鹃(Rhododendron lapponicum)凋落叶在不同雪被关键期(雪被形成期、雪被覆盖期和雪被融化期)腐殖化过程中胡敏酸和富里酸累积特征。结果表明:经过一个冬季,6种凋落叶胡敏酸碳和富里酸碳含量在各雪被关键期均表现出随雪被厚度减少而增加的趋势,而净累积量表现出在雪被形成期和融化期随雪被厚度减少而增加、在雪被覆盖期随雪被厚度减少而减少的趋势,且均受到凋落叶初始酸不溶性组分含量的影响。同时,不同雪被斑块下6种凋落叶胡敏酸碳均累积且净累积量为四川红杉康定柳岷江冷杉高山杜鹃红桦方枝柏,而除红桦外的其他5种凋落叶富里酸碳均出现不同程度的降解且降解量为四川红杉高山杜鹃康定柳方枝柏岷江冷杉红桦。这些结果清晰地表明,未来气候变暖情景下冬季雪被的减少可能促进高山森林凋落叶腐殖质累积,但在雪被覆盖不同时期受到雪被斑块特征和凋落叶基质质量的调控。     

Seasonal dynamics of organic components in fresh foliar litters at different gap positions in an alpine forest on the eastern Tibetan Plateau

Journal of Soils and Sediments - The organic components in fresh litters are important chemical traits for evaluating the initial quality that controls decomposition of plant litter. This study...     

Geographical extrapolation of forest soil acidification using pH(KCl) data: A case study

Soil acidification over the last three decades in three forest areas situated in northern Belgium (Region of Flanders), is assessed by comparing recent data of soil analysis with historical data. It is investigated whether acidification values of sites evenly spread over the region, averaged per soil group, can be used to assess acidification in specific forest areas. Results suggest that data obtained by this kind of geographical extrapolation do not differ significantly from measured data. In sandy soils however, a stop of acidification as measured by the pH(KCl), is observed at pH(KCl) values lower than 3.3.     

Decomposition and substrate quality of leaf litters and fine roots from three exotic plantations and a native forest in the southwestern highlands of Ethiopia

Substrate quality and decomposition (measured as CO₂ release in laboratory microcosms) of fresh leaf litter and fine roots of Cupressus lusitanica, Pinus patula, Eucalyptus grandis and native forest trees were studied. Changes in litter chemistry in each forest stand were analysed by comparing fresh leaf litter (collected from trees) and decomposed litter from the forest floor. Elemental concentrations, proximate fractions including monomeric sugars, and cross polarisation magic-angle spinning (CPMAS) ¹³C NMR spectra were analysed in leaf litters, decomposed litter and fine roots. Leaf litters and fine roots varied in their initial substrate chemistry with Ca concentration in leaf litters being higher than that in fine roots. In each stand, fine roots had a higher acid unhydrolysable residue (AUR) (except for the Pinus stand), higher holocellulose concentration and lower concentration of water-soluble extractives (WSE) and dichloromethane extractives (NPE) than fresh leaf litter. Likewise, ¹³C NMR spectra of fine roots showed lower alkyl and carboxyl C, and higher phenolic (except P. patula), aromatic and O-alkyl C proportions than leaf litters. Compared with fresh leaf litter, decomposed litter had lower concentrations of potassium, holocellulose, WSE, NPE, arabinose and galactose, similar or higher concentrations of Mg, Ca, S and P, and higher concentrations of N and AUR. CPMAS ¹³C NMR spectra of decomposed litter showed a higher relative increase in signal intensity due to methoxyl C, aromatic C, phenolic C and carboxylic C compared with alkyl C. In a microcosm decomposition study, the proportion of initial C remaining in leaf litter and fine roots significantly fitted an exponential regression model. The decomposition constants (k) ranged between 0.0013 and 0.0030 d⁻¹ for leaf litters and 0.0010-0.0017 d⁻¹ for fine roots. In leaf litters there was a positive correlation between the k value and the initial Ca concentration, and in fine roots there was an analogous positive correlation with initial WSE. Leaf litters decomposed in the order Cupressus>native forest>Eucalyptus∼Pinus, and fine roots in the order Pinus>native forest>Cupressus∼Eucalyptus. In each stand the fine root decomposition was significantly lower than the leaf litter decomposition, except for the P. patula stand where the order was reversed.     

Ecological niches of major soil types in Russia: Geographical aspects of the new Russian soil classification system

The factors of soil formation are not directly taken into account in the new profile-genetic Russian soil classification system; they are not reflected in the names and diagnostics of the soils. At the same time, as well as in many other modern soil classification systems, including the American Soil Taxonomy and the WRB system, the choice of the diagnostic criteria, the establishment of the relationships between them, and the setting of the quantitative boundaries between the soil taxa are based on our perception of soil geneses with due account for the factors of soil formation. In contrast to the ecological-genetic soil classification system of 1977, information on the factors of soil formation in the new system is encoded in the properties of the soil horizons. In some cases, this is insufficient for the definite geographic localization of soils and complicates the practical application of the new classification system. In this context, information on the ecological niches of soil types was included in the field manual on soil correlation-an abridged version of the soil classification system published in 2008—in the form of special tables developed for native and agrogenic soils. The analysis of these tables made it possible to outline certain geographic regularities in the distribution of soil types belonging to the trunk of postlithogenic soils.     

发酵床养猪废弃垫料的资源化利用评价

发酵床养殖技术是基于控制畜禽粪尿排放与污染的一种新型生态养殖模式,但其有机废弃物的处理和应用值得进一步研究.本文测定了我国山东、吉林两省5个发酵床养猪场的废弃垫料的有机质、氮、磷、钾、重金属元素、抗生素和盐分含量以及有害微生物数量.结果表明,废弃垫料中富含有机质、氮、磷、钾等营养元素.其中有机质含量为42.62％～54.12％,全氮1.54％～2.12％,全磷(P2O5)2.24％～5.55％,全钾(K2O)0.57％～2.15％;Cu、Zn、Cr、As、Ni、Pb、Cd、Hg等8种重金属元素含量均符合国家有机肥料农业行业标准(NY 525-2012)和城镇垃圾农用控制标准(GB 8172-1987)的限量标准;土霉素(Oxytetracycline,OTC)、四环素(Tetracycline,TC)、金霉素(Chlortetracycline,CTC)等四环素类抗生素含量低,环境风险小;蛔虫卵和大肠杆菌含量均超过NY 525-2012和GB 8172-1987的规定限值,蛔虫卵死亡率范围为90％～94％,总大肠杆菌的数量范围为1.29×105～2.24×106cfus/g;垫料盐分含量达到22.11～45.71g/kg.评价结论:发酵床废弃垫料具有有机肥料的基本性质,但是盐分含量偏高;肠道寄生虫卵严重超标,具有生物安全隐患,施用前必须对其进行无害化处理.     

北京养殖鸡舍发酵床废弃垫料资源化利用评价

发酵床养殖技术是基于控制畜禽粪便排放与污染而发展起来的一种新型养殖技术。通过对不同养殖场发酵床废弃垫料理化性质进行测定,判断其是否能够直接作为有机肥料施用到土壤中。结果表明,废弃垫料中富含有机质、全氮、全磷、全钾等营养元素。其中有机质43.19%~53.95%,全氮2.28%~2.66%,全磷(P2O5)2.36%~2.70%,全钾(K2O)2.80%~3.62%,均符合国家有机肥料农业行业标准(NY 525—2012)。但废弃垫料中p H值为8.03~8.93,EC为3 679~4 310μS/cm,大肠杆菌数量在48.00×104~52.00×104cfu/g之间,沙门氏菌数量在18.33×102~38.33×102cfu/g之间,种子发芽率指数为15.88%~31.52%。在废弃垫料资源化利用方面,发酵床废弃垫料虽具有有机肥料的基本性质,但是其p H值偏碱性,盐分含量偏高,存在使我国北方土壤碱化、土壤盐渍化风险;大肠杆菌严重超标,具有生物安全隐患;种子发芽率指数低,说明废弃垫料中存在抑制种子萌发的毒素。因此施用前必须对养殖发酵床废弃垫料进行无害化处理。