THE TRAPPING OF FLY-ASH PARTICLES IN THE SURFACE LAYERS OF SPHAGNUM-DOMINATED PEAT

The movement of fly-ash particles in a sequence ofSphagnum moss was studied in laboratory experiments and field investigations. The data obtained in the laboratory show that only 0.8% of particles, placed on the surface of a 6–10 cm thickSphagnum layer, were washed out with water (700–750 mm) during the 241 days of the experiment. The majority of added particles were fixed in the upper part (90% in 1–3 cm) of the moss layer. A SEM study indicates that sorption is slightly species-dependent due to the micromorphological parameters of theSphagnum species. The storage of particles bySphagnum mosses allows the use of natural sequences to study the history of atmospheric pollution. The distribution of particles in the upper part of moss layers in Viru Bog (50 km east of Tallinn, North Estonia) shows good agreement with the known air pollution history in Tallinn.     

REAL-TIME MEASUREMENT AND INTERPRETATION OF THE CONDUCTIVITY AND pH OF PRECIPITATION SAMPLES

A microprocessor-based acid rain monitor was used to make real-time measurements of conductivity and pH of rainwater within individual storms. The automated measurements were compared with laboratory analyses of a subset of the samples taken. The laboratory measurements tended to overestimate the pH because of temperature induced changes in dissociation and Henry's Law constants affecting ionic compounds in the rainwater. The measurement artefact due to these effects may result in average hydrogen ion concentrations being underestimated by approximately 10 to 15% at UK sites. The greatest systematic discrepancies would be anticipated at highly polluted sites and during low temperature acidic episodes. The concept of a rainwater acid fraction was investigated and found to be useful fro quality control and interpretative purposes. The field measurement of conductivity of low ionic strength samples was slightly lower than the corresponding laboratory measurement, possibly caused by limited resolutio nof the conductivity probe or dissolution of fine particulate material.     

用~(32)P标记测定楝科植物油对柑桔木虱的拒食作用

<正> 本文报道用~(32)P 标记柑桔枝芽条,研究楝科植物油对柑桔木虱(DiaphorinaCitri Kuwayama)的拒食作用。用定标器测得处理组(喷楝科植物油)虫体中的~(32)P 强度明显比对照组虫体巾的~(32)P 强度低,表明处理组的虫子比对照组的虫子吸食量小,2%苦楝(Melia azedarach)油和2%印楝(Azadirachta indica)油对柑桔木虱成虫在非选择条件下具有一定的拒食作用。用处理组和对照组的虫子所做     

土壤盐分分布特征评价

通过室内积水入渗土壤盐分运移模拟试验 ,分析了水盐迁移特征 ,并针对盐碱地干排法的特点 ,提出了一些土壤盐分变化特征量。同时分析了这些土壤盐分变化特征量和水盐迁移特性间的关系 ,为确定合理的盐碱地改良措施提供指导     

THE PERCOLATION OF RAINWATER THROUGH SOIL DEMONSTRATED BY FLUORESCENT DYES

Twelve fluorescent dyes were tested in the laboratory for their stability under conditions of alternate wetting and drying, and persistence of fluorescence in the presence of an acid soil. The strongly fluorescing Pyranine cone, was most suitable for tracing water percolating through soils. In the field this dye could be detected in the soil after several months and couldbe photographed in ultraviolet light. The greater percolation of water against tree trunks and lateral movement in the humus layer were demonstrated.     

THE APPLICATION OF MULTIVARIATE ANALYSIS TO SOIL STUDIES

The assumption that the variation of soil can be characterized by the variation of a set of relatively few soil properties is examined. Different sets of properties describing the same soil profiles, in particular those measured in the field, and those measured in the laboratory, are used to group these profiles by principal components analysis. This numerical method is used so that each set is grouped by exactly the same procedure. Data from the Riverina plains of New South Wales and some Cotswold (Gloucestershire) beechwoods are examined in this way and a close correspondence found between grouping based on field and laboratory data separately. The results cannot be generalized, though the method is suitable for any area. In particular, the results are unlikely to hold if comparisons are made between single properties.     

青藏高原的隆起对高山土壤形成的影响

素有“世界屋脊”之称的青藏高原是地球上最年青的大高原,也是一个独特的土壤区域.本文主要论述青藏高原的隆起对高山土壤形成的影响,对本区主要土壤类型和区域特征也有所讨论,意欲对高山土壤的发生、分类和土壤区划提供一些资料.     

THE INFLUENCE OF IONIC ENVIRONMENT ON THE NATURE OF IRON OXIDES IN SOILS

The colour in a sequence of soils formed on basalt in the Burnie area of Tasmania changes from red to red-brown near sea level to a yellow-brown in the more elevated areas. This colour change reflects the variations in the goethite/haematite ratio which in turn has been positively correlated to the proportions of Ca plus Mg on the exchange complex. The results support the laboratory observations of Schellmann that the adsorption of Ca and Mg ions by freshly precipitated iron oxide gel directs the ageing towards haematite.     

THE MEASUREMENT OF SOIL-WATER HYSTERETIC RELATIONSHIPS ON A SOIL MONOLITH

Soil water properties of an undisturbed uniform soil monolith were studied under laboratory conditions. Water content, hydraulic conductivity and soil water suction were measured simultaneously on a full cycle starting from saturation, drying to a small water content and then wetting until saturation was reached again. The results showed clearly the hysteretic nature of the relations between water content and suction and between hydraulic conductivity and suction, but not between hydraulic conductivity and water content.     

土壤的干湿变异与片状结构的发展

一、片状结构形成的原因很多,但在地表常见的一种可能不是沉积、水冻或压力等原因造成,而系常经干湿变异的结果。二、在干湿变异条件下产生的片状结构分布地区甚广,可能其形成与土壤种类无直接关系。凡地面少植被、原缺乏结构的土壤,如不受人为翻动,露于地面一定时期后,多半会产生不同明显程度的片状结构。三、土壤在干湿变异条件下产生片状结构可能为一简单的机械作用。即土块湿润时膨胀,体积变大,再经干燥,体积不能恢复,留下横向裂隙于土中,遂成片状结构。在所研究的各因子中,干湿变异次数多、干湿变异程度大以及干湿变异中脱水速率快均能促使土块膨胀,所以能使片状结构形成更为明显。如对土块施以压力,不予膨胀,虽土块具有各方面生成片状结构的良好条件,仍不能形成片状结构。对田间具片状结构土块的试验中,说明它可能与室内人工片状结构有相同的成因,一方面也说明了这种结构的不稳定,易于破坏,但如条件适合,形成也不困难。四、此种片状结构因系土块干燥时产生横向裂隙所形成,所以结构横轴生成的方向主要决定于水分的蒸发面而经常与之平行。这种关系在野外具体表现为结构横轴常与地表平行,在室内的几项试验结果与此也相符合。此外结构横轴形成的方向是否与土块湿润时水分进行的...     

马颊河流域影响土壤盐渍化的几个因素的研究

本研究是根据马颊河流域区域水盐动态监测预报分区定量化的要求进行的室内模拟试验,采用了扰动土的土柱法。试验进行分干土柱的毛管水上升湿润锋的观测与湿土状态的蒸发两个阶段。共3个组合21个处理,在人为控制条件下,仅就地下水(潜水)矿化度、耕层土壤有机质、土体构型等三因素对土壤盐渍化的影响,进行了观测。试验表明:地下水矿化度与土壤积盐量之间存在着极显著的正相关;耕层有机质的含量在1.5%开始有明显的抑制土壤盐渍化的作用;明确了在有粘土夹层的土体中,不能以在风干土柱的毛管水上升速度来推测土壤表层返盐的快慢,而应以在湿润土时,土壤水的蒸发速度为依据。粘土夹层的抑盐作用是随其厚度的增加和层位的升高而加强。     

VARIABILITY IN THREE AREAS OF THE DENCHWORTH SOIL MAP UNIT. III. SOIL GROUPING BASED ON CHEMICAL COMPOSITION

Data from a chemical determination of 21 elements plus seven Soil Survey routine laboratory measurements for three horizons of 30 soil profiles have been treated by multivariate techniques to find relationships and grouping of soil properties in soils mapped as Denchworth series. The samples profiles were developed in parent materials of Oxford, Kimmeridge and Gault clay origin. The Oxford clay grouping was confirmed, but the Kimmeridge and Gault clay soils were better represented by three rather than two classes.     

THE RESIDUA SYSTEM OF CHEMICAL WEATHERING: A MODEL FOR THE CHEMICAL BREAKDOWN OF SILICATE ROCKS AT THE SURFACE OF THE EARTH

The residua system of chemical weathering is here defined as the chemical sink towards which the bulk of earth's surface materials (i.e. the silicate rocks) trend during weathering. Chemically the system is defined in terms of four major components, SiO₂–Al₂O₃–Fe₂O₃–H₂O, evidence being derived from relative solubilities of components under earth-surface conditions; from experiments in which weathering environments have been simulated in the laboratory; and from field studies of rocks and their weathered mantle. The residua system can be used as a framework to construct mineral facies diagrams showing assemblages of the commonest earth-surface minerals that occur within it: quartz, gibbsite, goethite, kaolinite, halloysite. In a qualitative manner the facies diagrams can then be interpreted in terms of the partial pressure of water (PH₄O) and the temperature, T. The usefulness of this approach in systematizing studies of soil genesis is illustrated with reference to the weathering of granite.     

THE EFFECT OF TEMPERATURE ON THE MICROBIAL TRANSFORMATION OF [14C] GLUCOSE DURING INCUBATION IN SOIL

When two different soils were incubated after the addition of [¹⁴C] glucose in the dark at winter temperatures or at 5°C in the laboratory and then hydrolysed, radioactivity was detected in all seven common soil sugars except arabinose. In contrast, in incubations at 20°C, little radioactivity was found in the xylose. Examination of the microflora showed that the number of viable bacteria was one-tenth at the lower temperatures, whereas the numbers of yeasts, fungi, and actinomycetes were unaffected. Analysis of cultures of representative microbial isolates showed that none of the fungi or actinomycetes and only 3 per cent of the bacteria synthesized xylose, compared with 85 per cent of the yeasts. It is concluded that when these soils are incubated at low temperatures xylose is synthesized principally by yeasts.     

MINERALOGY AND MORPHOLOGY OF SALT EFFLORESCENCES ON SALINE SOILS IN THE GREAT KONYA BASIN, TURKEY

Samples from fifteen salt crusts from the central Great Konya Basin, Turkey, were studied in the laboratory. Chemical analyses data were combined with the results of X-ray diffraction. In the mineralogical systems studied, three types of salt efflorescences of different morphology were distinguished, with mirabilite/thenardite, bloedite, and bloedite/epsomite/halite as major mineral associations. These crusts seal the surface soil more or less effectively, thus reducing evaporation and thereby preventing cracking of the saturated soils. The effectiveness of this sealing depends on the morphology of the accumulated salt minerals rather than on their chemical composition. Reclamation of salt-encrusted spots therefore requires understanding of the mineralogy and the morphology of the efflorescent salts.     

小麦根-土界面磷的分布规律

在人工气候室采用32P标记土壤和土-根平面系统研究小麦根际磷的分布。结果表明，小麦根-土界面磷呈亏缺分布，但在报表0.5mm以内，大约培养15天左右磷常出现相对累积。磷的亏缺强度在高含水量和低空气湿度时较大。随培养时间的延长，磷亏缺量和亏缺范围随之增大。此外，磷亏缺量以中下部根系较大。根-土界面磷分布以方程C／Co＝a＋blnX或C／Co＝aXb拟合为优;时（t）空（X）作用下的磷分布可用t和X三次非线性多项式拟合。     

STUDIES ON THE DECOMPOSITION OF PLANT MATERIAL IN SOIL. IV. THE EFFECT OF RATE OF ADDITION

Different amounts of ryegrass roots and tops, both uniformly labelled with ^{1 4} C, were mixed with soil and allowed to decompose for 155 days under controlled conditions in the laboratory at 25°C. Initially the roots decomposed more slowly than the tops but by 155 days this difference had disappeared. About a third of the added plant C remained in the soil at the end of 155 days, about as much as when the same plant materials were incubated in the same soils for 6 months in the field. To a first approximation, the amount of labelled CO₂–C evolved was directly proportional to the amount of labelled plant C added. This held throughout the incubations. However, a slightly smaller percentage of the added plant C was evolved with small additions than with large, although this effect was on the limits of detection. Slightly more labelled plant C was retained in a soil rich in organic matter (2.43% C) than in an otherwise similar soil with less organic matter (0.97% C).     

非均质饱和土壤盐分优先运移的随机模拟

在室内使用特殊形状的土柱隔板成功地填装了在水平横截面上呈“川”字型分布、由质地相差较大的两种土壤相间构成的非均质土柱。当土柱出流达到稳态后，灌入CaCl2溶液，监测土柱出流液的浓度动态。通过计算表征氯离子迁移时间随机特征的概率密度函数，对出流盐分的优先运移采用传递函数模型进行仿真，并对构成非均质土柱的两种均质土壤分别进行了条件类似的水盐入渗实验和模拟。在此基础上获得了参与氯离子输运的土壤水运移体积和可动体积以及土壤溶液中氯离子的体积平均驻留浓度。     

南京近郊不同质地黄棕壤水分动态及其与杉木生长的关系

土壤水作为一个肥力因素,与林业生产有着密切的关系,许多国家的土壤学者都把它作为评价森林土壤生产力的关键因素之一^[6]。Zahner对于水分张力与林木生长曾作过详述^[7];而对于土壤有效水与杉木生长的关系,我国也曾有过报道^[3]为了进一步研究不同质地土壤的水分动态,近年来我们在南京近郊东善桥吉山附近本所幼龄杉木试验林,选择不同土壤质地的标准地,进行土壤含水量和杉木生长量的定位观察研究,以探索不同质地土壤水分动态与衫木生长的关系。现将试验结果叙述如下。