贵州东部地区茶园土壤甲螨种类调查研究

报道了贵州东部地区茶园土壤甲螨111种，分属38科。以奥甲螨科、单翼甲螨科、盲甲螨科、菌甲螨科、上罗甲螨科等为茶园土壤甲螨优势类群，新小奥甲螨、卵角单翼甲螨、棒菌甲螨等为茶园土壤甲螨类动物常见种类。     

影响钴在新疆荒漠区土壤中的形态分布因素研究

[目的]考察不同pH、重金属钻初始浓度、陈化时间和离子强度对土壤中钴化学形态分布和生物有效性的影响。[方法]采取经典Tessier连续提取技术。[结果]随着处理土壤pH的升高,有机物结合态含量呈下降趋势,两者间有极显著的负相关（相关系数=0．800～,P〈0．01）,残渣态随pH升高呈上升趋势,生物有效性在pH5时达到最大值。在研究初始钴浓度范围内,随着外源钴浓度的浓度的增加,土壤中钴的碳酸盐结合态和可交换态所占总钴的比例减小,生物有效性系数（K）呈明显的递减趋势,当钴浓度大于250mg／L时,K递减趋势较大;土壤环境离子强度在O．01mol／L附近时,除残渣态外各形态钴在土壤中分布的比例达到最大值,当离子强度大于0．01mol／L时,生物有效性系数降低,限制了土壤中钴的迁移性。在考察陈化时间内,土壤陈化10d时,钴的生物有效性系数最大。[结论]各形态含量均随土壤介质pH、重金属钴初始浓度、陈化时间和离子强度有所变化,不同程度地影响着重金属钴在土壤中的富集状况。     

On the determination of total heavy metal content in saline soils and soils rich in organic matter

Abstract

Methods of soil decomposition for determination of heavy metal total content were considered. Two saline soils (chloride and sulphate solonchak solonetz) and one rich in organic matter were uzed for investigation. It has been established that decomposition by using HF‐HCl with a preliminary ignition at 500°C is a very suitable method. The type of the studied soils and the results obtained allow for this method to be recommended for decomposition of various soils.

On the basis of experiments with modelled soils it has been proved that possibilities for heavy metal losses on ignition are created when NaCl content and the percentage of weakly bound heavy metals (water‐soluble, exchangeable, etc.) are high. Under the conditions of the experiment (acid soils ‐ pH 4.3 and 5.0) losses of Zn and Pb but not of Cu have been incurred. Although these cases are not typical, this requires the applicability of the method for such particular occasions to be checked.     

Influence of residual phosphate fertilizer on labile and extractable zinc in hawaii soils

Abstract

Zinc availability was studied using five soils from Hawaii which had histories of massive phosphorus applications. Heavy phosphate fertilization usually increased extractable Zn, irrespective of the extractant used. The extra extractable Zn associated with the added P probably came from Zn as an accessory element in the fertilizer. Treble superphosphate commonly used in Hawaii contains about 1400 ppm Zn. The Zn content of phosphate fertilizers must be considered before making statements about the effect of fertilizer P on Zn solubility and availability in soils.

Two solutions (0.1N HCl and 0.005M DTPA) were compared as Zn extractants for Hawaii soils. DTPA extracted less Zn than 0.1N HCl. Zinc extracted by repeated HCl treatment was more closely related to the labile Zn pool (E‐values and L‐values) than was DTPA‐extractable Zn. The results suggest that 0.1N HCl extractable Zn, Zn E‐value and Zn L‐value measured the quantity of a single fraction of soil Zn.

Repeated extraction of soil with 0.1N HCl seems to be a suitable procedure for evaluating the Zn status of acid, highly weathered soils of Hawaii.     

Specificity of soil functioning and formation on gas-bearing areas

Background, aim, and scope  Exploited gas fields and underground gasholders are specific sources of increasing methane concentration. Methane migrates into the soils by diffusion and convection through natural and technogenic cracks in geological structures and influences the function of the soils. Soil cover of gas-bearing area functions as a specific, bilateral, periodically penetrating, geomembrane. Soils shield, transform, and differentiate migrating fluxes of technogenic-allochthonous methane, preventing its emission to the atmosphere. Problems of methane’s emission are rather current at the present, as methane is the second in importance after CO₂ greenhouse gas, since its concentration in the atmosphere annually grows by approximately 1%. By global estimations, methane emissions in the gas industry make about 8% of annual receipt to the atmosphere, equal on the average to 500 Тg per a year (Cicerone and Oremland, Global Biogeochem Cy 2:299–327, 1988). But these calculations are based on the account of the technological losses making 3–12% from the mining of natural gas. The contribution of migratory methane fluxes to the atmosphere, as a rule, is not considered. The need for research of soil cover functioning on gas-bearing areas is explained by the fact that processes of methane oxidation, its transformation in soils, and emission to the atmosphere at these objects are now practically not being studied. The aim of our study was to reveal specific processes of soil function and formation on gas-bearing areas by an example of underground gasholder. Materials and methods  The material was sampled in 1998–2003 at the territory of underground gasholder located in Albeluvisol’s zone in Russia. According to the comparative-geographical method, 51 soil profiles have been studied in similar litologically geomorphological conditions in various geochemical zones: in the industrial zone, in the zone of gas dissipation, and at the regional background. The total square of investigated territory is about 60 km². Six soil profiles were investigated in seasonal dynamics. Samples of soils for physical, chemical, and microbiological analyses were taken from each horizon of soil profiles (202 samples). Samples of soil air for a definition of methane concentration were taken from depths of 20, 40, and 60 cm. Methane emission to the atmosphere was measured near soil’s cuts and, in addition, on all area of the investigated territory at knots of squares network through 700–1,000 m, in total at 32–42 points in May, July, and November. Years of investigation have been split by technological and hydrothermal conditions. The periods with the normal and lowered compression of gas in gasholder, dry and warm, and damp and cool years have been allocated. It has influenced the soil function processes and considered an interpretation of the data received. Results  The changes of functional parameters of soils at a gas-bearing area influenced by methane fluxes migrating from gas deposits, in comparison with background soils, are revealed. Such functional parameters are methane concentration in the soils, activity of its bacterial oxidation, methane emission to the atmosphere, and oxidation–reduction potential. Spatial and temporary dynamics of these parameters at gas-bearing and background territory are investigated. Discussion  Methane interaction with soil’s air is in its ascending (descending) and lateral diffusion and convection in soils. Methane fluxes dissipate in porous space of soils forming gas anomalies. The technogenic-allochthonous methane concentration strongly varies in soil’s air on gas-bearing area (1–10,500 ppm) and, on average, exceeds the autochthonous, microbiologically produced methane at background territories. Migratory methane is deposited on diffusion and sorption barriers. The capacity of diffusion barrier depends on effective coefficient of diffusion, the attitude of air and general porosity, and granulometric composition and sharply differs in auto-, semi-hydro-, and hydromorphic soils reaching maximum in hydromorphicity and among the soils with identical water content—in heavy soils. The capacity of the sorption barrier is defined by abiotic methane absorption and a specific surface of soils and grows with their increasing intensity in soils to a heavier granulometric composition or into soils with peat and gleyic horizons. The low sorption capacity leads to an increase of methane concentration in the soil’s air and decreases its utilization by microorganisms, in which its quantity depends on sorption properties. The central component of functioning that promotes a number of essential transformations in soils on gas-bearing areas is methane interaction with the biotic phase. The periods of methane deposition by diffusion and sorption barriers are used for biological methane oxidation and formation of biogeochemical barriers in soils. The activity of bacterial methane oxidation is characterized by spatial variability and depends on the entrance of methane, defined by granulometric composition, soil moisture, the attitude of air and general porosity, Eh, organic matter content, and salinization. During interaction between technogenic-allochthonous methane and soil on diffusion, sorption, and biogeochemical barriers, its transformation occurs, accompanied by a strengthening of variability of oxidation–reduction potential and formation of pedogenic, bacteriomorphic, and nanodispersic magnetic oxides of iron. Conclusions and perspectives  Specificity of soil functioning on a gas-bearing area is in interaction of technogenic-allochtonous methane with solid, liquid, gaseous, and living substance of the soil system. Spatial laws of soils functioning on gas-bearing area in the Albeluvisol’s zone are revealed. Distinctions of soil functions depending on litologically geomorphological conditions are shown. The greatest changes of parameters of functioning under the influence of technogenic-allochthonous methane occur in automorphic soils, and it is less in semi-hydromorphic soils. Activity of bacterial methane oxidation in soils, emission, and consumption from the atmosphere and their spatial laws are characterized by the time dynamics depending on hydrothermal and technological conditions of seasons and years. During oxidation in soils of gas-bearing areas, carbon of methane is concentrated on a biogeochemical barrier that is shown in the increase of methylotrophic microorganisms’ biomass and leads to a high variability and decrease of Eh and to the formation of magnetic oxides of iron. Recommendations  Results of research can be used for carrying out ecological monitoring and an estimation of tightness of objects of the gas industry. Activity of bacterial methane oxidation, Eh, and magnetic oxides of iron can be used as diagnostic parameters of soils on gas-bearing areas. This paper has been developed from a presentation at the conference SUITMA-4 (Soils in Urban, Industrial, Traffic, Mining and Military Areas) Nanjing, China, 2007     

华北北部沙质潮土区冬小麦需肥特征及施肥技术

华北北部沙质潮土区冬小麦产量较低,为摸清区域内冬小麦养分吸收规律,提高施肥效率,通过田间试验研究了区域内冬小麦养分吸收动态及不同肥料因子对产量的影响,结果表明:该区域冬小麦养分吸收速率最快时期出现在拔节期至抽穗期,生育后期的养分吸收比例相对较低;氮磷钾配合施用不仅可以提高冬小麦的养分吸收量,还可以促进养分向子粒中运转;增加冬小麦有效穗数及调节产量构成因素间的平衡关系,是提高产量的有效田间管理措施;控制养分投入数量,调整养分投入比例,保持养分持续供应强度,增强土壤对养分投入的缓冲能力是提高产量的有效施肥技术。     

Straw Management Effects on Organic Matter Mineralization and Salinity in Semiarid Agricultural Soils

The impact of straw incorporation (6 Mg ha -1 year -1 ) into agricultural soils compared with straw removal on organic matter mineralization and salinity was studied. The mineralization coefficient (CO 2 -C evolved/organic C ratio) was obtained to evaluate organic matter mineralization. Soil salinity was measured as means of electrolytic conductivity of saturation paste extract. Both parameters were measured seasonally during two years in two salt-affected soils of the semiarid Central Ebro Valley (northeast Spain), a saline soil and a saline-sodic soil. The electrolytic conductivity (ranging from 2.5 dS m -1 to 24.3 dS m -1 ) and the mineralization coefficient (ranging from 5.9 10 -4 day -1 to 37.9 10 -4 day -1 ) varied widely during seasonal samplings of both soils. The lowest electrolytic conductivity values, coincided with the highest mineralization coefficient values. Straw mulching and burying decreased significantly the average seasonal electrolytic conductivity of both soils: 2.5 times in the saline soil, and 1.9 times in the saline-sodic soil. The EC reduction only increased significantly (P < 0.05) the mineralization coefficient on saline soil (1.6 times). Straw amendment, followed by rainy periods, allowed the soluble salts leaching but did not modify significantly sodium content. A logarithmic regression was found between mineralization coefficient and electrolytic conductivity (r 2 = 0.41), considering both soils. Infiltration, water aggregate stability, and qCO 2 were improved with the straw amendment, but only in saline soil. Soil differences showed the existence of a double effect: an osmotic and a specific ion effect.     

几种土壤在单一Zn及Cd Cu共存条件下对Zn的吸附

研究了Zn2+在单一及与Cd2+、Cu2+共存条件下在塿土、黄绵土、黑垆土、黄褐土、砂土5种土壤中的吸附特征,并探讨了其吸附机制。结果表明,在20℃、30℃下,Zn2+在各供试土样中吸附等温线总体上均呈I或III型等温线形式,总体上黑垆土、塿土对Zn2+吸附最强,而砂土的吸附总是最差;塿土、黄绵土和黄褐土中Zn2+吸附的温度效应呈现升温正效应特征,砂土中则总体上表现出随温度上升呈下降趋势,黑垆土中Zn2+吸附的温度效应则与重金属处理有关。Freundlich模型是描述Zn2+吸附等温线最佳模型。Cd2+、Cu2+的共存对Zn2+的吸附均具有显著的拮抗作用,但对Zn2+吸附规律的影响不同。机理分析表明,Zn2+在土壤中的吸附主要以化学吸附为主,Cu2+由于其与Zn2+相似的化学吸附特点而竞争Zn2+化学吸附点位,但Cd2+吸附主要竞争以电性引力形式吸附的Zn2+,因而Cu2+对Zn2+吸附的影响较大,而Cd2+影响较小。     

海南砖红壤的微形态特征以及南方网纹红土与砖红壤环境意义的差异

主要运用土壤微形态学、粘土矿物学和土壤化学方法,对海南岛三个不同母质的砖红壤剖面的微形态特征和成壤过程进行研究,并将网纹红土和砖红壤进行比较.结果表明,砖红壤典型的微形态特征为易风化矿物颗粒和粘粒胶膜的缺失、均质状的b-垒结以及风化成因铁锰质结核的出现;典型的成壤过程为强烈的化学风化、红化、均质化、淋溶以及显著的脱硅富铝化过程.随着成土母质和土壤排水条件的变化,砖红壤的微形态特征亦有所差异.而我国南方的网纹红土的发育程度低于砖红壤,不宜被划分为砖红壤或氧化土,而更趋向归入老成土,在我国土壤发生学分类中大致相当于红壤.