Field-based partition coefficients for trace elements in soil solutions

A total of 48 elements was detected in the soil solutions centrifuged from two acid sandy (humus-iron podzol) profiles from southern England. Concentrations ranged from mm for the major ions to mm for trace metals such as U and the rare earth elements. Field-based solid/solution partition coefficients, K_d, were determined by calculating the ratio of the amount of an element extracted by 0.43 m HNO₃ or a neutral salt (0.01 m CaCl₂ or 0.1 m Ba(NO₃)₂) to the concentration in the soil solution. These partition coefficients did not show the expected trend in selectivity. For example, Cd consistently had one of the highest K_d values, higher even than Cu. This was thought to be due in part to the nature of the K_d which reflects a balance between binding to the soil solids and to the dissolved organic carbon (DOC), which is present at relatively high concentrations (1–20 mm ) in the soil solutions. Because of the underlying functional similarity between metal binding by the solid and dissolved organic matter, the partition coefficient (and hence element mobility) will be relatively insensitive to changes in pH and metal-ion activity in the soil solution.     

江西鄱阳湖平原区农田土壤微量元素空间分异特征及其影响因素

【目的】开展土壤微量元素空间分异及其影响因素的分析,能更客观地阐明土壤微量元素变化的内在机理,对田间土壤肥力的有效管控和保障人类健康、保护土壤生态环境具有重要意义。【方法】在江西省丰城市鄱阳湖平原农田区,采用网格布点法布设283个采样点,每个采样点取0-20 cm表层土壤,对样点数据用三倍标准差法剔除异常值20个,实际利用样点数为263个,分析了土壤样品pH、质地、氮、磷、钾和硼(B)、锰(Mn)、钼(Mo)、硒(Se)、碘(I)、氟(F) 6种微量元素的含量。采用地统计学理论、方差分析、相关分析以及回归分析方法,对鄱阳湖平原区农田土壤6种微量元素的含量、空间分布特征及其影响因素进行分析。【结果】B、Mo含量均值处于丰富与上限值之间;Mn含量均值为330.24 mg/kg,处于缺乏水平;Se、I含量均值处于适量水平;F含量均值为474.59 mg/kg,处于边缘水平;6种微量元素含量均为中等程度变异,但各元素含量变异程度有所差异。B、Mn、Mo元素的最优插值模型为指数模型,Se、I、F均为球状模型。I元素的块金效应<25%,其他5种微量元素处于27.09%~41.77%。6种微量元素含量的空间分布格局差异较为明显,除Se元素不缺乏外,其余5种微量元素均处在缺乏水平。B、Mn、F含量均受到土壤类型、耕层质地的显著影响,Mn、Mo含量与坡度、pH间均达到极显著相关水平,Mn、Se、I含量与全磷含量显著相关,坡向与到河流的距离与6种微量元素含量未达到显著相关关系,其他影响因素仅对某些种元素表现出显著或极显著相关关系。在B、I含量的主要影响因素中,以耕层质地的影响最大;在Mn、Mo元素含量的主要影响因素中,以pH的贡献率最高;Se元素含量与土壤类型、全磷、坡度、高程之间达到显著或极显著相关水平,以全磷的影响程度最高;F元素含量与土壤类型、耕层质地、全氮含量相关显著,且全氮为主要影响因素。【结论】1)研究区域土壤B、Mo的含量总体较高,I、Se含量适量偏上,Mn总体上较为缺乏,F处于边缘水平;6种元素含量均为中等程度变异。2)土壤微量元素B、Mn、Mo的最优插值模型为指数模型,Se、I、F则为球状模型;除I具有强烈的空间自相关外,其余5种元素表现为中等程度的空间自相关。3)微量元素含量影响因素中,坡向、到河流的距离与各元素含量间未达到显著相关关系;B、I含量均受耕层质地的影响最大,Mn、Mo含量主要受pH的影响,Se含量主要受全磷的影响,F元素含量则主要受全氮的影响。     

云南山地胶园土壤肥力空间变化特征

对云南西双版纳、普洱、红河、临沧植胶区的16个橡胶种植农场开展系统规模化的土壤肥力普查及评价,以全面了解云南山地胶园的土壤肥力特征,为云南山地胶园橡胶树施肥方案制定和土壤质量提升提供依据.研究结果表明,云南山地胶园土壤肥力空间变异较大,不同植胶区胶园土壤肥力状况不尽相同,同一植胶区不同农场胶园土壤肥力状况亦有差异.云南...     

基于土壤类型和微量元素辅助信息的土壤属性空间模拟

为探讨大尺度区域土壤属性空间化的方法,以吉林省为例,研究土壤养分（pH值、有机质、速效磷、速效钾和碱解氮）和地形地貌、微量元素等变量之间的关系;并在考虑土壤类型基础上,将相关性较高的变量作为协因子进行土壤养分的Cokriging插值研究。结果表明,pH值与经度、有效铁、锰和速效氮的相关系数分别高达-0.66、-0.71、-0.70和-0.67;有机质与经度、pH值、有效钙、锰的相关系数分别为0.55、-0.58、0.56和0.52;碱解氮与经度、纬度、pH值、有效铁、锌的相关系数分别为0.57、-0.57、-0.67、0.56、0.54;速效磷与速效钾、有效锌的相关系数分别为0.67和0.64。分析发现以相关性较高的微量元素作为协因子进行Cokriging插值精度均优于采用地形变量作为协因子的Cokriging插值。交叉检验和检验站验证结果表明,与普通Kriging相比,基于土壤类型和微量元素的Cokriging插值在增加估值精度方面有所提高。     

Spatial variation in soil phosphomonoesterase in irrigated and dry farmlands

Spatial variation in the content of acid and alkaline phosphatase was surveyed on two farmlands. Two adjacent plots, one irrigated and cultivated and the other nonirrigated and cultivated, were marked on a 300-m-long transect with 10-m spacing. Soil samples were collected at the depths of 0–30 and 30–60 cm and were then analyzed for acid and alkaline phosphatase and other soil parameters. The analytical results were then subjected to classical statistical and geostatistical analysis. The results showed that the correlation coefficients of the phosphatase and clay, the silt, the sand, the mean weight diameter, the geometric mean diameter, the equivalent CaCO₃, the pH, the electrical conductivity, the organic carbon, the respiration, the Olsen available phosphorus, and the vesicular arbuscular mycorrhizae (VAM) spore numbers of the soils in the transect studied were highly significant. In both layers of the irrigated farmland, the coefficients of the variation of the acid phosphatase were relatively high and the coefficients of the variation of the alkaline phosphatase were relatively low compared to those of the dry farmland. Although the acid and alkaline phosphatase in the topsoil and subsoil of the farmlands exhibited a spatial dependence at the sampled scale, the stability of the spatial structures were markedly low. Published in Russian in Pochvovedenie, 2006, No. 5, pp. 569–573. The text was submitted by the authors in English.     

典型绿洲区土壤盐分的空间变异特征

针对绿洲区存在的土壤盐化制约干旱区农业可持续发展问题,应用面域土壤信息调研采集,结合地统计学与GIS技术对新疆典型绿洲区土壤盐分空间变异特征进行研究。研究结果表明：0～30 cm耕层土壤盐分呈现强变异性,30 cm以下土层呈现中等变异。各土层土壤盐分均呈现中等空间自相关性,空间相关距离在24～28 km范围内。各等级盐化土在不同深度土层的分布方位基本一致。各土层非盐化土面积均占主导地位,都占研究区总面积的69%以上;其次为轻度盐化土面积,占研究区总面积的19%～30%;各土层中度盐化土面积都在3.4%以下;重度盐化土仅在0～30 cm土层有极少量分布。随着土层深度的增加,非盐化土和中度盐化土的面积逐渐减小,轻度盐化土面积逐渐增大。本研究对于指导干旱区绿洲农业生产、保障区域土壤资源可持续合理利用具有重要的理论价值和明确的实际应用前景。     

Spatial variation of peat soil properties in the oil-producing region of northeastern Sakhalin

Morphology and properties of medium-deep oligotrophic peat, oligotrophic peat gley, pyrogenic oligotrophic peat gley, and peat gley soils on subshrub-cotton grass-sphagnum bogs and in swampy larch forests of northeastern Sakhalin have been studied. Variation in the thickness and reserves of litters in the studied bog and forest biogeocenoses has been analyzed. The profile distribution and spatial variability of moisture, density, ash, and pH_KCl in separate groups of peat soils have been described. The content and spatial variability of petroleum hydrocarbons have been considered in relation to the accumulation of natural bitumoids by peat soils and the technogenic pressing in the oil-producing region. Variation of each parameter at different distances (10, 50, and 1000 m) has been estimated using a hierarchical sampling scheme. The spatial conjugation of soil parameters has been studied by factor analysis using the principal components method and Spearman correlation coefficients. Regression equations have been proposed to describe relationships of ash content with soil density and content of petroleum hydrocarbons in peat horizons.     

Spatial variation of tracer distribution in a structured clay field soil

Within the sensitive soils of the River Oder Basin (E Brandenburg, Germany), chloride‐tracer transport was studied with respect to soil‐surface conditions of the well structured clayey topsoil (disturbed vs. undisturbed) and irrigation mode (flooding vs. sprinkling). The spatial variation of chloride and dye distribution was sampled in a regular grid within different soil depths. Different methods were used for the analysis of spatial heterogeneity: a heterogeneity index HI derived from fitting parameters of the cumulative distribution function, semivariogram analyses to identify the spatial representativity of observations and to classify the spatial variation, and Spearman's rank correlations to examine the spatial similarity of tracer distribution across different soil depths. Soil aggregation was obvious throughout the soil profile, and macropores and fractures were preferred flow paths for the tracer. Flood irrigation resulted in more “uniform” distribution than sprinkling did. However, preferential flow was identified for all treatments, where, once established below the surface layer, flow paths led to heterogeneity indices manifesting nonuniform flow and reduced lateral mixing between macropores and soil matrix. Within the flooded plot, spatial structure of chloride concentration was moderate unlike the strongly structured variation within the sprinkled plots. For purposes to generalize and to assess regional risk of the water and solute transport within the topsoil of the River Oder Basin, spatial autocorrelation ranges of about 15 cm should be considered and included into concepts of soil protection and land‐use management, soil‐sampling strategies, or modeling approaches.     

三工河流域绿洲土壤微量元素有效含量特征分析

土壤微量元素的含量与分布特征是反映特定地区环境状况的一个重要因素,对土地资源的合理开发和利用具有重要意义.本研究以天山北坡三工河流域冲积平原型绿洲为研究区,选择盐土、潮土和灰漠土3种土壤类型,分析其B、Mn、Zn、Fe、Cu等微量元素的有效含量特征.结果表明:⑴以"全国农业系统的土壤速效微量元素丰缺指标"为标准,土壤有效Mn含量属于极低水平,有效Zn和Fe含量属于中等水平,有效Cu属于丰富水平,有效B属于极富水平;⑵三工河流域绿洲土壤中有效Mn、Zn、Fe、Cu含量与土壤pH呈负相关关系;土壤有机质对有效Fe、Cu含量影响很大;有机质和Mn的关系不明显,这和湿润地区研究结果存在显著差异;⑶不同的土壤类型对于土壤有效B、Zn和Fe的含量影响显著;潮土中微量元素的有效含量与盐土、灰漠土中含量相比有显著差异.     

沧州市优质果品产区土壤中碘的空间变异特征

以沧州市优质果品产区泊头、沧县和献县3县表层土壤(0～20cm)全碘为研究对象,利用地统计与GIS技术相结合的方法研究了该地区土壤中全碘的空间变异特征。结果表明沧县和献县表层土壤中全碘数据呈正态分布,符合指数模型,泊头表层土壤中全碘数据经对数转换后符合高斯模型。沧县和献县表层土壤全碘具有较强的空间相关性,说明受气候、土壤母质、地形、土壤类型等自然结构性因素影响较大;泊头表层土壤全碘具有中等的空间相关性,说明由人类活动等随机因素引起的空间变异起很大作用。采用Kriging最优插值法得到了3县表层土壤全碘含量的空间分布图,结果表明研究区内3县表层土壤全碘的空间分布不均匀,主要受当地的水文地质地形影响,河流两岸及低洼地带全碘含量较高,反之则低,而某些地区全碘含量由于受到人类活动的影响也表现出局部的异常性。     

吉林省中部平原区土壤有效态中微量元素的空间变异特征

运用地统计学方法结合GIS技术研究了吉林省中部平原农业区土壤中微量元素的空间分布特征,通过对数转化、域法处理和Box-Cox转化3种数据处理方法对土壤有效钙、有效镁、有效硼、有效铜和有效锌进行了正态分布性检验。结果表明,Box-Cox转化成功地使有效钙、有效镁、有效铜、有效锌含量数据更好地服从正态分布,而域法处理能使有效硼含量数据更好地服从正态分布,削弱了异常值的影响。应用地统计学分析方法进行了半方差函数的计算和最适合模型的拟合,得出各元素最好的理论模型,并绘制了各养分元素的空间分布图。半方差分析的结果显示,各元素具有中等空间相关性。     

Spatial distribution of soil trace element concentrations along an urban-rural transition zone in the black soil region of northeastern China

Journal of Soils and Sediments - Urbanization is an important process that changes land use pattern and the sustainability of agroecosystems in the urban-rural transition zone. Through intensified...     

玉米生长后期的根系分布研究

为了研究玉米生长后期根系的生长发育规律,利用中国气象局固城农业气象试验站大型根剖面系统,采用微根管观测系统及方形整段标本法和地下根系室玻璃窗,对‘屯玉46号’玉米根系的生长状况进行了试验研究。结果表明:垂直方向上,方形整段标本法和微根管法测得的根长密度占整层总根长密度比例的变化趋势一致,相关系数分别为0.987和0.717,且两种方法在0~20 cm土层的根长密度比例均为最大。0~60 cm土层为玉米根系生长活跃区,方形整段标本法测得根长密度生长量为其余层的4倍。两种方法测得的根长密度无显著差异,相关系数为0.830,均匀性水平较好。玉米成熟期根系的水平幅度较乳熟期窄,下层根系仍处于生长中,垂直深度增加。玻璃窗与方形整段标本法观测的根深测定结果存在差异,这可能与观测环境条件不一致有关。     

Monthly variation of forage and soil minerals in central Florida II. trace minerals

Abstract

A two‐year study was conducted to determine the trace mineral status of cattle grazing forages (bahiagrass) and soils on a ranch in central Florida. Forage and soil samples were collected every month for two years. Month effect (P < 0.05) on soil trace mineral concentrations were observed in manganese (Mn) and zinc (Zn) in years 1 and 2, and in copper (Cu) and iron (Fe) only in year 2. All soil trace minerals studied showed higher (P < 0.05) concentrations in year 2. Month differences (P < 0.05) in forage trace mineral concentrations were found in cobalt (Co), Cu, Fe, Mn, molybdenum (Mo), selenium (Se), and Zn. The majority of forage trace minerals were higher in spring‐summer months. Year means were similar (P > 0.05) in forage trace mineral concentrations. Few and low correlation coefficients were observed between and within soil and forage trace minerals concentrations. Percentages of total forage collected with trace minerals below critical values (in parentheses) and suggestive of deficiency were as follows: in forage, Co (0.1 ppm), 93%; Cu (8 ppm), 98%; Fe (50 ppm), 75%; Mn (40 ppm), 41%; Mo (> 6 ppm), 0%; Se (0.2 ppm), 98%; and Zn (25 ppm), 84%; in soil, Cu (0.3 ppm), 77%; Fe (2.5 ppm), 7%; Mn (5 ppm), 91%; and Zn (1.5 ppm), 53%.     

Chloroform-labile trace elements in soil via fumigation-extraction: Steps towards the soil microbial ionome beyond C:N:P

Secondary and trace elements may be limiting soil microbial functioning, albeit microbial demand and content remain largely unknown and methods for their in situ detection are limited. Thus, the objective of the present study was to take the first step towards the method development for the assessment of the soil microbial ionome, that is, the elemental composition of soil microbial communities. Chloroform (CHCl₃) fumigation extraction was used for the detection of microbial CHCl₃-labile secondary and trace element concentrations in soils. The suitability of two extractants (NH₄NO₃, CaCl₂) for the quantification of CHCl₃-labile concentrations of phosphorus, sulphur, potassium, sodium, and magnesium, as well as selenium, iron, zinc, manganese, copper, cobalt, nickel, molybdenum, vanadium, boron, silicon, barium, arsenic, and cadmium, were tested in six agricultural soils. Additionally, three soil to extractant ratios (1:5, 1:10, and 1:20) and two extraction durations, 1 or 2 h, were tested in a subset of two soils. Out of the two extractants tested, 0.01 M CaCl₂ was found to be the best-suited extractant. For CaCl₂, a soil-to-extractant ratio of 1:20 with an extraction time of 1 h was best for the majority of elements in the two soils tested. In a limited number of agricultural soils, we were able to show that CHCl₃ fumigation extraction can successfully be applied to the elements phosphorus, sulphur, potassium, sodium, magnesium, zinc, manganese, copper, nickel, vanadium, boron, silicon, and barium to yield a CHCl₃-labile element fraction. Conversion values to microbial biomass, accounting for elements contained in the cell envelope components, which are mostly not extractable, and to account for adsorption to soil colloids during extraction are yet to be determined in a larger variety of soils. To overcome some of the limitations of the fumigation extraction approach for secondary and trace elements, a pre-extraction step may provide a suitable solution.     

Spatial variation of soil respiration in a coastal protection forest in southeastern China

Purpose

Forest soil respiration is an important component of global carbon budgets, but its spatial variation is inadequately understood. This research aimed to measure soil respiration (R _s), soil water content (M _s-5), soil temperature (T), and carbon dioxide (M _co2) in a coastal protection forest (CPF), which is one kind of man-made forests designed for coastal protection primarily along the coast in China, to determine the relationships among them, and to analyze their spatial distributions in a small scale.

Materials and methods

We measured R _s, M _s-5, T, and M _co2 of 100 plots in an approximately flat grid (totally 4 hm²) by LI-8100A in a Casuarina equisetifolia L. forest on a state-owned forest farm of 326 hm² in SE China. Traditional statistics and geo-statistics including semivariance, Moran’s I index, and fractal dimension were used to analyze data.

Results and discussion

Key findings were that (1) the spatial mean of R _s, M _s-5, T, and M _co2 were 1.194 μmol m^?2 s^?1, 11.387 mmol mol^?1, 14.153 °C, and 407.716 ppm, respectively, in the forest; (2) the relationship between soil respiration and the other three factors was weak, while M _s-5, T, and M _co2 have strong relationships with each other; and (3) the four factors, especially soil respiration, had strong autocorrelation within given limits and showed great heterogeneity with 95 % confidence intervals around the means in the study area, all of which can provide important value for the study of carbon cycling and for the sustainable management of coastal protection forests.

Conclusions

According to geo-statistical analysis and field investigations, soil respiration in the coastal forest is less than in some broad-leaf forests but higher than in some conifers. Strong heterogeneity and autocorrelation are clear; however, its relation with other three factors is weak. CPF is a considerable potential forest for carbon conservation if it is well managed.

     

A multivariate approach for anomaly separation of potentially toxic trace elements in urban and peri-urban soils: an application in a southern Italy area

Purpose

Geogenic soil enrichment and anthropogenic pollution by potentially toxic trace elements (PTEs) are two processes acting together. Although it is often difficult, it is necessary to separate the two processes for risk assessment and understanding the environmental implications. The aim of this study was to analyse the soil concentrations of various PTEs in a southern Italy area in order to: (1) determine their different correlation structure to isolate sources of variation acting at different spatial scales and (2) to define potential anomalies based on the correlation structure.

Materials and methods

In the urban and peri-urban area of Cosenza-Rende, 149 topsoil samples were collected (0.10 m) and analysed for different elements by X-ray fluorescence spectrometry. Principal component analysis and factorial kriging analysis were used to map the spatial distribution of PTEs in topsoil and to identify the main factors influencing their spatial variability.

Results and discussion

Two groups of PTEs were identified: the first group included As, Pb and Zn; and the second one Al, Co, Cr, Fe, La, Nb, Ni, Ti and V. The first group was related to anthropogenic causes, while the second one was more related to parent rock composition. The regionalized factors at different scales of variability allowed to aggregate and summarize the joint variability in the PTEs and consider the probable causes of soil pollution.

Conclusions

The study allowed analysing and quantifying the sources (environmental or anthropogenic) of variation of PTEs acting at different spatial scale and defining the spatial anomalies based on the correlation structure associated at the different spatial scales.     

基于多源数据的土壤水分反演及空间分异格局研究

温度植被干旱指数(TVDI)是一种通过反演土壤水分来反映土壤干旱状况的重要方法。在TVDI的基础上引入数字高程模型(DEM)数据对地表温度进行校正,能够减少地形起伏对能量二次分配的影响。用阈值将研究区分割成不同土地利用类型,结合野外同步实测数据,用分段反演模型反演渭-库绿洲土壤水分分布图,并对渭-库绿洲土壤水分的空间格局和分异规律进行分析。结果表明:(1)地形校正后的TVDI能够更好地反映土壤水分状况;(2)土壤水分总体上从西至东,由北向南降低,在绿洲内部较为稳定,在交错带变化较为剧烈,土壤水分垂直变异系数呈现幂函数递减的整体变化趋势;(3)针对研究区不同土地利用类型用分段反演模型进行反演,有效地实现优势互补,总体上提高了土壤水分的反演精度,在区域土壤水分研究中值得关注和应用。     

Patterns in trace elements in lichens

Water, Air, & Soil Pollution - Epiphytic lichens were sampled in a Dutch national monitoring survey, which was carried out twice within 5 yr. The samples were analyzed by neutron activation...