稻田土壤对铵的矿物固定对土壤保氮作用的贡献

为了定量评价土壤对铵的矿物固定作用在土壤对肥料氮的保持作用中的相对贡献,通过室内培养试验和分析测定,研究了湖南省几种主要母质发育的水稻土对添加铵的矿物固定作用及其对土壤保氮作用的贡献。结果表明:土壤对外源铵的矿物固定是土壤重要的保氮机制之一,但不同土壤对保氮作用的相对贡献大小不一,以河沙泥的固铵作用对土壤保氮作用的贡献最大,固铵量占总保氮量的51.5%,红黄泥最低,固铵量仅占总保氮量的17.1%,其余五种土壤的固铵作用对土壤保氮作用的贡献大小顺序依次是黄泥田(43.7%)、湖潮泥(35.5%)、紫泥田(35.4%)、灰泥田(25.0%)、麻沙泥(20.8%)。     

模拟酸雨对红壤铝形态的影响

用动态淋洗试验，研究了不同pH的模拟酸雨对红壤中铝形态和性质的影响．结果表明，酸雨淋洗引起红壤中盐基离子的淋失和土壤铝的溶出．随着酸雨溶液pH的降低，盐基淋矢量和铝溶出量增加．酸雨淋洗影响土壤铝形态的转化，使红壤中交换态铝上升，吸附态羟基铝有所下降．这说明在酸雨长期作用下，羟基铝溶解，并转化为交换态铝和引起铝的溶出，使铝进入环境，危害生态系统．     

Geochemical evidence of pollutants from coalfired generating stations in late Pleistocene palaeosols in the Dalijia Shan,northwestern China

Surface palaeosols in two tills and a diamicton from an area in northwestern China were analysed for geochemical pollutants. Elevated levels of Br, As and Sb indicate that pollution from coal-burning and/or coal-fired electricity generating stations is delivered by aeolian transport into palaeosols dating from the last glaciation. Because the climate in the field area is sub-humid (precipitation <760 mm) the relative movement of soluble elements in palaeosols dating from early and late stades of the last glaciation is not expected to be high. The glacial and aeolian parent materials of the palaeosols indicate differences that are probably related to their source areas and to the incorporation of geochemical pollutants.     

铜陵矿区土壤中镉存在形态及生物有效性

采取Tessier连续提取法，研究铜陵矿区不同功能区表层土壤中镉的化学形态分布和生物有效性。结果表明，各种土壤中的镉含量全部高于地区背景值，主要来源与矿业活动有关，部分样品还有矿体的风化富集叠加，土壤镉污染指数PCd为1．15～79。镉含量依次为矿体风化土壤→废矿堆下垫土→市郊菜地土→矿区铜草土、路边土和稻田土→其它土壤。其形态分布，酸性土壤中以Fe-Mn氧化态和可交换态为主，其余三态相对较低；碱性土壤中有机态和残渣态比例较高，碳酸盐态和可交换态所占的比例低。土壤中生物可利用态镉的含量较高，占土壤总镉的60．20%-98．3％，生物不可利用态仅占1．7％-39．2％。     

表面活性剂对可离子化有机化合物在黄土中吸附行为的影响

研究了2，4-二氯苯酚、2，4-二硝基苯酚和苯甲酸三种可离子化有机化合物在天然黄土和阳离子表面活性剂改性黄土中的吸附行为。讨论了DH值、离子强度和二价重金属阳离子对可离子化有机化合物在改性黄土中吸附的影响。提出了可离子化有机化合物在改性黄土中的吸附模型，吸附等温曲线可分解为两条分别代表离子和非离子形态的等温吸附曲线；其吸附行为可用双模式吸附理论来解释。在2，4-二硝基苯酚共存时，苯甲酸在改性黄土中的吸附量减小，证明竞争吸附的存在。     

Reconnaissance soil geochemical survey of Gibraltar

The extreme density of population of Gibraltar, situated at the southern tip of Spain, exerts considerable pressure on land use and thus future planning is of utmost importance. An initial reconnaissance soil geochemical survey of Gibraltar was based on 120 surface samples (0–15 cm) taken from a wide range of exposed, either bare soil or vegetated sites, to provide the optimum geographical distribution. The total elemental concentrations of 26 elements (Li, Na, K, Be, Mg, Ca, Sr, Ba, Al, La, Ti, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Pb, P, S, As) were determined by nitric/percholric acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The reconnaissance data shows that the spatial distribution of various elements depended on previous and present land use. Most elements (Ca, Cr, Mg and Mn excluded) exhibited relatively high concentrations in civilian and natural soils. Trends have been established for many elements, and concentrations exceeding guideline values have been found in certain areas of Gibraltar. This reconnaissance of Gibraltar is at present being followed by a more detailed baseline geochemical survey, which will establish the extent and magnitude of the variations in major and trace elements in soils and dusts, assess the impact of industrial, commercial and urban development on the geochemical landscape and to make recommendations concerning sustainable development.     

中国水稻土碳循环研究进展

文章首先分析了水稻土在碳循环研究中的地位和重要性，进而对我目水稻土碳循环的研究现状作了较为详尽的阐述，对其主要研究结论进行了深入的剖析。中国大而积的水稻土自1980年以来显示出有机碳库增加现象，说明水稻田对大气CO2可能产生汇效应。水耕熟化过程足有机碳的积累过程，水稻土的碳密度是早作土碳密度的2-3倍。水稻土的同碳能力与土壤的微团聚体的粒径有关。但对于水稻土中有机碳的分布和结合状态与农业管理措施、水稻土质量变化、农业生态环境变化的关系仍不清楚。因而建议就这一问题从土壤物理学、化学和生物学的相互作朋与土壤微团聚体中矿物质、有机质和微生物的相互结合关系的层面上进行多学科研究。同时提出了今后我困水稻土碳循环的重点研究方向和领域，即从整体和系统的角度来研究碳循环和平衡，从不同的时空区域来研究碳循环的过程和强度。     

Concentrations of Potentially Toxic Metals in Urban Soils of Seville: Relationship with Different Land Uses

Fifty-two samples of surface soils were taken in the urban area of Seville, to assess the possible influence of different land uses on their metal contents and their relationship with several soil properties. The samples corresponded to five categories or land uses: agricultural, parks, ornamental gardens, riverbanks, and roadsides. Sequential extraction of metal according to the procedure proposed by the former Community Bureau of Reference (BCR) was carried out, and pseudo-total (aqua regia soluble) metal contents were determined. Lower organic C, total N and available P and K contents were found in riverbank samples, probably due to the lack of manuring of those sites, left in a natural status. In contrast, significantly higher electrical conductivity was found in those sites, due to the tidal influence of the nearby Atlantic Ocean. Other land uses did not show significant differences in the general properties. Concentrations of Cu, Pb and Zn, both aqua-regia soluble and sequentially extracted, were clearly higher in soils from ornamental gardens, whereas the concentrations in the riverbank samples were slightly lower than the other categories. In contrast, other metals (Cd, Cr, Fe, Mn, Ni) were uniformly distributed throughout all land uses. A strong statistical association is found among the concentrations of Cu, Pb, Zn and organic C, suggesting that the larger contents of these metals in ornamental gardens are partly due to organic amendments added to those sites more frequently than to other kinds of sites. Considering the conclusions of previous studies, heavy traffic can also contribute to those `urban’ metals in urban soils. Periodic monitoring of the concentrations of urban metals in busy city centres and of the quality of amendments added to soils of recreational areas are recommended.     

A Geochemical Survey of Topsoil in the City of Oslo, Norway

The city of Oslo is situated centrally in the Oslo-graben, which is a Permian rift basin consisting of different kinds of volcanic and sedimentary rocks. In the summer of 1998, approximately 300 samples of surface soil (2–3cm) were taken systematically, 1km^–2. The investigated area covers about 500km². Samples were dissolved in 7M HNO₃ and analysed for 29 elements with ICP-AES, mercury with cold-vapour technique (CV-AAS) and arsenic and cadmium with a graphite furnace (GF-AAS). A factor analysis is frequently used to identify relationships among sets of interrelated variables. To describe the covariant relationships among the elements, a factor analysis has been completed. The first factor contains the elements Sc, Fe, Li, Co, Al, Cr, Be, K, Ni, V, Mg, Y, Ba, Zr, Mn and As (listed with decreasing communality). These elements are typical for the minerals in the area and most of these elements have a near normal distribution. Sources for this factor are probably geological. The second factor contains Cd, Hg, P, Zn, Cu, Ba and Pb. They have a log-normal distribution. Road traffic is probably one of the sources contributing to this factor. In Norway studded tyres are used frequently in the winter season which results in large amounts of road dust. Leaded petrol has been a major source for Pb but is not in use any more. Wear and tear of tyres and brakes contribute also to this factor. Other sources contributing to this factor are probably industry, rubbish incineration, crematoria and release of some of these elements from structural material by fire. Factors 3, 4 and 6 with elements such as Ca, Na, La, Ti and Sr probably have geological sources. They are associated with minerals like amphiboles, pyroxenes and feldspars and some of the elements are from sea aerosols. Factor 5 contains Mn, Cd, Zn, As and Pb. Manganese may be derived from many different sources such as rock weathering, windblown dust, agriculture and traffic. Since As and Mn are placed in both factor 1 and 5 they probably have both geological and anthropogenic sources. Concentrations of the elements in the second factor are much higher in the central parts of Oslo, than in the rest of Oslo. The median value of Hg in the centre is 0.48mgkg^–1, which is 8 times higher than that in the rest of the city. Also, the other elements have much higher levels in the centre. The industrial district north-east of the centre also has high values. The distribution of arsenic is regular throughout the whole city, but has a slightly higher level in the centre. Norm values for contaminated land used by the Norwegian authorities are 2mg As kg^–1 and 25mg Cr kg^–1. Of 297 samples, 61% contain more than 25mg Cr kg^–1 and 79% more than 3mg As kg^–1, which is the detection limit of the analysis. These samples will therefore be regarded as contaminated. Factor analysis places these elements in the geological factor. The Norm value of zinc is 150mgkg^–1, and 40% of the samples contain more than this. The Norm value of lead is 150mgkg^–1, and 35% of the samples contain. Road traffic is probably the major source for these elements.     

西安地区土壤CO2 释放量和释放规律

根据碱溶液吸收法,对西安地区不同植被条件下土壤CO2释放量进行了昼夜观测,观测资料显示,西安地区各月份土壤CO2释放量在一昼夜内具有明显的变化,从当日上午到次日上午,CO2释放量表现出由低变高再变低的规律,土壤CO2释放量变化与温度变化具有相同的特征,但释放量的变化具有滞后性,相对于温度的变化滞后4－6h左右,温度是决定土壤CO2释放量昼夜变化规律的主要因素,它的升高和降低分别造成了土壤CO2和放量的增加和减少,不同植被条件下,土壤CO2释放量不同,林地释放量大于草地,草地释放量大于裸地,夜间12h释放量大于白天12h释放量。