Boron in soils and plants of the West Transbaikal region

Some particularities of the distribution of boron in the main types of soils were studied. A close dependency between the boron content in the soils and its concentration in the soil-forming rocks (r = 0.85) was established, as well as the absence of a correlation between the content of boron and that of humus. It was found that boron is an element with an average intensity of accumulation in plants: the coefficient of its biological absorption from the soil of the steppe, meadow, and agrocenoses varied from 1.2 to 3.2. A correlation between the bulk content of boron in the soils and its accumulation in plants was absent (r = −0.07–0.11). The vegetation of a significant part of the steppe, dry-steppe, and forest-steppe landscapes had a boron deficiency (30–75%).     

Cadmium contamination of soils and rice plants caused by zinc mining

Characteristics of heavy metal contamination in paddy soils were discussed with respect to the soil and field conditions influencing the metal contents in rice.

1. In contaminated areas along the Kuzuryu River, the heavy metal contents of rice (expressed as the average of each area) were largely related to contents of paddy soils in 0.1 N HCl soluble forms as well as in total contents. A correlation was also found for the ratio of Cd to Zn in their soluble forms in the soil.

2. Within a given contaminated field plot, the heavy metal contents were not uniform, i.e: they were high around the irrigation inlet and decreased towards the outlet. However, these changes seemed to alter the Cd rice level much less than expected.

3. Soil pH and exchangeable Ca were negatively correlated with the Cd content of rice at a highly significant level. An un-drained field condition with a low soil Eh remarkably lowered the Cd content, particularly during rainy weather after the heading of the plant.

4. Based on a comparison of the extractable heavy metal contents in the waste ores and their contaminated soils, sulfide minerals derived from the mining appeared to be weathered more rapidly in the soil. With some extraction methods, the Cd origin was distinguished as the solubility of the metal in the soil among the waste products from the zinc mining and refinery.     

Risk assessment of Arbutus unedo L. fruits from plants growing on contaminated soils in the Panasqueira mine area,Portugal

Purpose

In the Panasqueira mine area, Arbutus unedo L. (arbutus tree) grows on soils developed on waste materials and on soils impacted by mining activity. The arbutus berry brandy is considered a product with economic value. The aims of this study were to evaluate the biogeochemical impact of the mining activity on soils and arbutus trees, to assess the possible risks associated with human consumption of the fruits and the derived brandy, and to evaluate the potential of the arbutus tree in phytostabilization.

Materials and methods

Soil samples (10–15 cm deep) developed on waste materials, on schists affected by seepage water or treatment plant effluents and on colluvium-alluvium materials were characterized (fraction <2 mm) for pH, particle size distribution, organic carbon (C_org), cation exchange capacity (CEC) and NPK by classical methodologies. Plant (A. unedo) samples (roots, leaves and twigs, and fruits) were collected at the same sites as the sampled soils, washed with tap and distilled water and dried at 40 °C. The elements’ concentrations in soils (total fraction—four-acid digestion and available fraction—diethylenetriaminepentaacetic acid extraction), plants (ashing followed by acid digestion) and brandy samples produced with fruits collected on contaminated and non-contaminated sites were determined by inductively coupled plasma atomic emission spectroscopy.

Results and discussion

The soils are mainly acid, silty loam, with variable values for C_org, CEC and NPK. They are contaminated with As (158–7,790 mg/kg), Cd (0.6–79 mg/kg), Cu (51–4,080 mg/kg), W (19–1,450 mg/kg) and Zn (142–12,300 mg/kg). The available fraction of the soils is quite variable between <0.04 and 76 % of the total, depending on the element. Trace elements’ concentrations, in leaves and twigs, are within the normal range for plants, except for Cd and Zn that, in some samples, are above the normal values, but without phytotoxic symptoms. Trace elements’ concentrations in fruits are low. The calculated hazard quotient for all trace elements in arbutus berry was <0.1. In the brandy, elemental concentrations are within the legal standards, except for Pb, whose higher concentrations may result from distillery equipment.

Conclusions

According to the EC 466/2001 legislation and with a hazard quotient of <1, the arbutus berry consumption does not constitute health risks for humans. The fruits can be used to produce local brandy. The concentration of copper in brandy is within the range established by the Portuguese legislation. Arbutus unedo can be used in the phytostabilization programs in the Panasqueira area, for it is a pioneer species and a non-accumulator of trace elements.     

Lead in boreal soils and food plants

The soils of the boreal zone, characterized by acidic, low-organic-matter sands in uplands and organic deposits in lowlands, represent unique environments for heavy metals. The mobility and plant uptake of Pb can be substantially different than in other soils. A survey of natural levels of Pb in northern Ontario revealed concentrations of 26 mg kg^–1 dry soil and 1.3 mg kg^–1 dry blueberry leaf, with an apparent plant/soil concentration ratio (CR) of 0.051. In outdoor lysimeters with an acidic sand profile (pH 4.9) and under a boreal climate, 67% of a pulse of Pb, applied as Pb(NO₃)₂, was essentially immobile over 4 yr. The 33% that leached may have been mobilized by soluble organic ligands or the N0₃ ^– companion ion. The solid/liquid partition coefficient (K_d) for this soil, using either applied ²¹⁰Pb or stable Pb, was very low: 20 L kg^–1 The CR for ²¹⁰Pb in the same soil was correspondingly high: 0.10 for blueberry and 0.059 over all crops studied. In two organic soils, the K_d values were 9 × 10³ L kg^–1 (Sphagnum, pH 4.8) and 3 × 10⁴ L kg^–1 (sedge, pH 5.5) with corresponding CR values of 8 × 10^–4 and 0.0085 for blueberries (0.0027 overall in the latter soil). The CR was most closely related to soil cation exchange capacity, although organic matter content and pH were undoubtedly important related factors. In combination, the acidic sand and organic soils of boreal settings represent extremes for the mobility of Pb.     

我国几种土壤中铁锰结核的元素组成和地球化学特点

The objective of this research was to isolate a dichlorvos （2,2-dichlorovinyl dimethyl phosphate）-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium （strain DDV-1） was successfully isolated and identified as an Ochrobactrum sp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L^-1 or 500 mg L^-1 dichlorvos and inoculated with 0.5% or 1.0% （v/v） strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation.     

Cadmium contamination of soils and rice plants caused by zinc mining IV. Use of soil amendment materials for the control of Cd uptake by plants

In view of the difficulty in practicing water management as a measure to prevent the production of high Cd rice, alkaline or calcareous soil amendment materials were examined, concerning their pH effect on the availability of soil heavy metals.

1. In the experiment conducted on the contaminated paddy field, the essential Cd uptake by the plant occurred after the ear-forming stage and was reduced remarkably by a basal application of the amendment materials followed by top application, depending on the activity of raising the soil pH. Combined use of calcium silicate and fused magnesium phosphate for a basal dressing was most effective on Cd uptake, producing rice of the lowest Cd content, one fifth of the control.

2. The content of Cu in rice also decreased with the treatment to an extent second to Cd, while that of Zn and Pb decreased in straw but hardly changed in rice. Cu seemed fastest in the straw-to-grain movement which was also promoted by the treatments.

3. Soil Cd and Cu were less soluble in 0.1 N HCl solutions than were Zn and Pb, with the application of fused phosphate. Soil Cd became more insoluble in the incubated soil in a submerged condition and its solubility appeared to be depressed by the addition of ammonium sulfate.

4. Based on the good results for the control of high Cd rice obtained through three years' survey in the problem area, it was recommended that these materials be used in sufficient quantity to raise soil pH, taking care not to cause delay in the first growth.     

Transport and accumulation of Cd ions in soils and plants

Direct measurements of adsorption coefficients of Cd-ions on soils were compared with adsorption coefficients derived from migration experiments in soil columns; reasonable agreement exists between the two sets of data. With the help of the adsorption coefficients, data from the literature on the uptake of Cd by plants and a mathematical model, the future accumulation of Cd was calculated for different types of soil to which Cd via sewage sludge will be applied. Cd-content of plants was also calculated. From the results it follows that if recently proposed Cd-application limits are adhered to these soils, accumulation will be prevented for a long time.     

Land use dynamics and nutrient characteristics of soils and plants along topo-sequences in inland valley watersheds of Ashanti region,Ghana

Surveys on land use dynamics were conducted over a 3-year period along various toposequences in benchmark inland valley watersheds of the Ashanti region, Ghana. Six typical land use systems were selected for more detailed studies, Le., primary forest (PF), cacao farm (CP), fallow (Fallow), mixed cropping (MC), and lowland rice-based systems including both traditional rice (TR) and sawah{ft1} (paddy)-based rice farming (Sawah). Topsoil samples (0-20 cm) and samples of leaves and bark of various plants were collected from these land use systems for nutrient characterization using laboratory analyses. The remaining primary and secondary forests cover only a patchy area, accounting for less than 20%, in forest reserves and surrounding areas. Cacao farms were developed both in the upland areas, middle slopes, and lowland areas, which occupied about 20% of the watershed. Lowland rice farming is estimated to account for about 10% of the watershed. Oil palm cultivation is also common in the lowland areas. The remaining land use systems were mostly fallow and mixed cropping of maize, cocoyam, cassava, and plantain. Plant leaves of various species in the lowland traditional rice area showed higher concentrations of phosphorus and potassium but lower calcium and strontium concentrations than those of the leaves in the upland surveyed plots, especially, the forest area. Nitrogen, sulfur, magnesium, and the other mineral elements, however, did not show any clear differences among the six land use systems. Bark samples tended to exhibit lower concentrations of nitrogen, phosphorus, sulfur, magnesium, sodium, silicon, aluminum, iron, manganese, and copper but higher concentrations of calcium and strontium. Cacao leaves showed silicon-accumulator characteristics and the magnesium concentration was high too. Cacao bark contained potassium and zinc in appreciable amounts in compared to the leaves. Topsoil samples of the primary forest and cacao farms in the upland areas showed higher levels of TC, TN, exchangeable Ca and Mg, and eCEC while the levels of available P showed a rather reverse trend compared to the lowland traditional and sawah rice plots. Topsoil samples of the fallow and mixed cropping plots at upland and fringe sites showed intermediate levels. The pH at the mixed cropping site was the lowest. These general fertility trends along upland and lowland topo-sequences were different from those of monsoon Asia and Japan. With the implementation of the sawah rice-based farming system, the inland valleys could contribute to the enhancement of sustainable food production in the country.     

Magnesium in barley plants on magnesium-deficient soils

Working with fused phosphate containing Mg, we have known some of the Mg-deficient areas in Shizuoka prefecture as a field problem. In these areas, crop plants develop visual hunger signs, resulting in restricted growth and reduced yield. The manurial effect of Mg-salt added or fused phosphate is remarkably excellent in these areas or soils.     

Elemental composition of serpentine plants depends on habitat affinity and organ type

Serpentine soils represent a stressful growing environment for most plants due to a number of edaphic factors, including low concentrations of plant nutrients and high concentrations of heavy metals. Plants in these environments range from weakly resistant to strictly endemic, yet it remains unclear whether serpentine habitat affinity affects plant chemistry, including elemental distribution among various organs. We address this knowledge gap using three confamilial pairs of endemic and non‐endemic plants. First, we determined total and phytoavailable soil concentrations of four nutrients (Ca, Mg, P, K) and three heavy metals (Co, Cr, Ni) across 11 serpentine study sites. Next, we determined the concentrations of these elements in leaves, flowers, and seeds in plants of each species growing on serpentine soil. Soils at the study sites were characteristically high in concentrations of Mg, Ni, Co and Cr, and low in K, P and Ca relative to non‐serpentine soils. Habitat affinity was critical in determining the organ concentrations of Ca, Mg, K, and Co, although concentration often varied by organ type. Relative to non‐endemics, endemics had higher concentrations of Mg and K across all organ types, whereas Ca concentrations were higher for non‐endemics in the leaves but equal for the two reproductive organs. While no difference was observed in Ni or Cr concentrations, endemics contained 56% less Co than non‐endemics across all organ types. These results suggest that serpentine endemics are more effective at acquiring potentially limiting nutrients compared to non‐endemic species, but both endemic and non‐endemic plants exclude most phytotoxic heavy metals. Therefore, growth on serpentine requires common physiological responses of all plants, though high variation in uptake of some key nutrients and exclusion of some metals may reflect differential adaptation to serpentines by non‐endemic and endemic plants.     

Cobalt in soils and plants of the Selenga River delta

The contents and distribution of cobalt in soils and plants of the Selenga River delta (the Buryat Republic) have been studied. It is shown that the cobalt content in the studied soils does not exceed the clarke value and is somewhat higher than the regional background value. Its distribution in the soil cover of the region is rather uniform. The concentration of cobalt in the aboveground phytomass is usually lower than its normal concentration in the vegetation of the world.     

酚类物质对土壤和植物的作用机制研究进展

酚类物质是重要的植物次生代谢物质之一,它对植物的生长、养分吸收、生理特性、酶活性以及生长环境中的土壤、微生物等都存在影响。本研究对酚类物质对土壤和植物的作用机制、植物生态系统中酚类物质的含量分布、酚类物质对植物生理生化特性的影响以及对土壤理化特性的影响进行探讨,展望农林生产实践中酚类物质的研究趋势,为解决农业和林业生产中因酚类物质的影响引起生产力下降问题提供依据。     

Macromolecular organic phosphorus in decomposing plants and in pasture soils

The acid-insoluble organic P in hayed-off phalaris was extracted at pH 7.0 using a detergent, and a macromolecular fraction (G50 phosphorus) was separated by gel filtration. Approximate amounts of nucleic acid P in this fraction were calculated from the purine base content of the fraction. Changes in the above organic P fractions were then monitored during plant decomposition. Acid-insoluble P increased as a result of decomposition whereas changes in G50 P and nucleic acid P were less pronounced.The neutral detergent extracted only a portion of the soil organic P from unimproved and improved pasture soils. The higher total organic P content of the improved soil was reflected in the G50 P content of the extract but not in its nucleic acid content.Microbial assimilation of the G50 P isolated from undecomposed and decomposed phalaris was rapid and virtually complete, and so most of the organic P in this fraction could not be expected to accumulate in soil. The assimilation of that portion of the G50 P which was eluted off ion exchange cellulose was much slower for soil samples than plant samples. The unassimilated portion from the soil samples was found to be free of nucleic acid bases and warrants further chemical examination.     

攀枝花矿区土壤对钒的吸附特征研究

钒(V)作为人和动植物所必需的营养元素,近年来日益受到人们的重视。钒具有造血功能,但在人体内过量则会引起急性或慢性中毒,损害皮肤、心脏及肾脏。钒的毒性随化合价的升高而增大,以V2O5及其他5价钒盐毒性最大。20世纪80年代末,联合国环境规划署已建议将钒列入环境危险元素清单表的优先位置[1]。鉴于钒对人体健康和生态安全的影响,国际化学物质安全署(IPCS)、联合国环境规划署(UNEP)和世界卫生组织(WHO)指出:“应在监测的基础上,加强钒的环境行为和生物毒理研究[2,3]”。因此,控制环境中钒污染具有重要意义。土壤中的钒主要来自工业废渣、废气中钒的扩散、大气沉降、积累;含钒废水灌溉农田;金属矿     

Elemental,functional group and infrared spectroscopic analysis of actinomycete melanins from brazilian soils

Eleven actinomycete melanins were characterized by elemental and functional group and infrared analysis. A soil humic acid from a Brazilian topsoil, a darkred latosol under savanna grassland, analysed previously, was used for comparative purposes. C, N, total acidity, COOH, and phenolic OH contents were within the ranges reported for soil humic acids and fungal melanins. Compared to the soil humic acid, the actinomycete melanins showed greater detail, indicative of higher aliphaticity. Most of these were, in varying degrees, similar to the type III IR spectra of humic acids, which are characteristically high in proteinaceous material, and with variable amounts of polysaccharides. The exceptions were two melanin spectra that showed more resemblance to the humic acid from the dark-red latosol, which belongs to the type I spectra of soil humic acids, a category that includes most soil humic acids. The probable participation of melanic actinomycetes in the formation of humic polymers in discussed.     

Absorption of atmospheric NO2 by plants and soils

Tomato, sunflower and com plants were grown in culture solution containing three different concentrations of ¹⁵N-Iabelled KNO₃ (260 ppm N, 105 ppm N, and 26 ppm N) as a nitrogen nutrient, and fumigated with 0.3 ppm NO₂ for 2 weeks during their vegetative stages. The amount of NO₂ nitrogen absorbed into the plants was estimated by “difference method” and “¹⁵N method.” “¹⁵N method” was found to give more probable values than “difference method.” According to “¹⁵N method,” the nitrogen derived from NO₃ was about 16% (tomato), 22% (sunflower), and 14% (com) of the increased amount of total nitrogen in the whole plants in the 105 ppm N plot, and these percentages increased in the 26 ppm N plot. Difference in nitrogen concentration of the culture solution resulted in big change in the dryweight increase of the tomato and sunflower plants, but the absorption rate of NO₂ nitrogen based on the dry weight changed slightly. The absorption rate of NO₂ nitrogen was around 0.8 mg (gDW)^-1 day^-1 in tomato and sunflower plants, and 0.3 mg (gDW)^-1 day^-1 in com plant. Leaves were found to be an active sink of NO₂ and the nitrogen of NO₂ seemed to be rapidly transformed into compounds of high molecules in the leaf cells.     

Microbiological characterization and nitrate reduction in subsurface soils

Summary Two borings (20 m depth) were performed in a sandy-clayey soil over a limestone bed and in a sandy soil with lumps of clay in some depths. Bacteria were found in the deeper soil layers of both profiles. The methods used to detect bacteria were those normally used for topsoil layers, plate counts of bacteria, ATP content, and direct microscopy. Measurements of CO₂ evolution showed that the potential for bacterial activity was present in all depths of the two profiles. However, the activity was strongly dependent on the presence of easily available organic C. An indication of the denitrification potential was obtained by measuring the N₂O evolution. Under aerobic incubation without the addition of glucose, N₂O was detected only in the topsoil. When glucose was added to the soil samples, N₂O was found at a low level in the deeper soil layers. Under anaerobic incubation, N₂O was detected in all deeper layers, and increased markedly when glucose was added to the soil samples.     

Uptake of fluoride and aluminum by plants grown in contaminated soils

Soils collected from areas at different distances from an aluminum smelter were studied to determine the soluble and labile F and soluble Al contents and availabilities to selected plants. Red maple seedlings (Acer rubrum L.) and orchard grass (Dactylis glomerata L.) were grown in pots containing the soils and after 3 mo foliar tissues were sampled and analyzed for the two elements. The soluble and labile contents of soil F as predictors of foliar F were compared. Significant decreases in soluble and labile F and soluble Al in soils were found with increasing distance from the smelter. As F levels in the soils increased, the F in the foliage of both orchard grass and maple increased. As Al in the soil increased, Al in maple foliage increased. Overall, F concentrations in plant foliage were below those considered as background. The results imply that, at least in the soils studied, the soil F content is not an important source of F to plants and therefore to herbivores in the area. Labile F values in the soils were significantly greater than soluble F at all sites, but, contrary to previous studies, soluble F was a better predictor of foliar F than was labile F.     

Psychrotolerant actinomycetes of plants and organic horizons in tundra and taiga soils

It has been revealed that in organic horizons and plants of the tundra and taiga ecosystems under low temperatures, actinomycetal complexes form. The population density of psychrotolerant actinomycetes in organic horizons and plants reaches tens and hundreds of thousands CFU/g of substrate or soil, and decreases in the sequence litters > plants > soils > undecomposed plant remains > moss growths. The mycelium length of psychrotolerant actinomycetes reaches 220 m/g of substrate. Application of the FISH method has demonstrated that metabolically active psychrotolerant bacteria of the phylum Actinobacteria constitute 30% of all metabolically active psychrotolerant representatives of the Bacterià domain of the prokaryotic microbial community of soils and plants. Psychrotolerant actinomycetes in tundra and taiga ecosystems possess antimicrobial properties.     

Recultivation in the Lusatian mining region —Targets and prospects

For more than 100 years, lignite is mined in open-cast mines in the Lusatian region of northeastern Germany. The increase of output quantities in the former GDR of up to about 200 million tons per year lead to problems for recultivation and loss of public acceptance. By 1993, about 39,000 ha of land were reclaimed, but 75,000 ha of land had been utilized by open-cast mining operations until that date. Forest recultivation has a tradition of more than 60 years and shows the ways for an economically acceptable recultivation by the mining industry. Agricultural recultivation of dumps is also performed successfully. Today, the future mining operation of LAUBAG being reduced to 5 open-cast mines uses specific overburden removal technologies in order to create favourable conditions for the arrangement of a safe, variable and Lusatia-typical post-mining landscape — the beginnings are already visible.