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Combination effects of heavy metals and fluoranthene on soil bacteria   总被引:16,自引:0,他引:16  
The effects of (1) Cd, Cu, Zn, and fluoranthene (FLA), separately applied, and (2) combinations of one of these heavy metals with FLA on the growth of bacteria were studied in agar plate experiments. The bacteria were extracted from A horizons of a Eutric Regosol and a Calcic Chernozem. Significant reductions of bacterial counts were observed for both soils at concentrations > 1.0 mg Cd l–1, 0.5 mg Cu l–1, and 0.5 mg Zn l–1, respectively. Additions of FLA up to 100 mg l–1 did not result in increasing reductions of bacterial growth in the Regosol. Only 0.5, 2, and 100 mg FLA l–1 caused significant reductions of 22–27%. Bacterial counts were not affected by 0.2 mg FLA l–1. Low concentrations of heavy metals which were not affective when added separately were found to reduce bacterial growth when applied in combination with 0.2 mg FLA l–1. At higher levels of heavy metals up to 2.5 mg l–1, addition of FLA also increased the toxicity of the metals. It is assumed that the enhancement of toxicity by FLA is due to an alteration of the permeability of bacterial cell membranes. Received: 19 July 1996  相似文献   

5.
Calcium chloride–extractable (1:10 soil/solution ratio, w/v) nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), organic nitrogen (EON), and Ntotal fractions were measured in two long-term experiments. Both experiments are located in the Great Hungarian Plain. The first experiment was established on a Luvic Phaeozem soil and the second experiment was on a Calcic Chernozem soil. Researchers investigated the effects of long-term fertilization and irrigation on the amounts of nitrogen (N) fractions. Nitrogen rates caused significant increase in NO3-N and Ntotal fractions. These fractions were in close correlation (r = 0.87; r = 0.88) with nitrogen balance. The nitrate content of the 200-cm-deep soil layer of soils under different nitrogen- and water-supply conditions were also studied. As an effect of N overfertilization, the maximum nitrate accumulation on nonirrigated plots occurred in the 200-cm depth, whereas on irrigated plots a nitrate accumulation layer could not be observed in the 200-cm-deep soil layer.  相似文献   

6.
Data of the agrochemical survey of arable soils in Belgorod oblast during the period from 1964 to 2014 have been analyzed. The soil cover mainly consists of typical chernozems (Haplic Chernozems) and leached chernozems (Luvic Chernozems) in the forest-steppe zone and ordinary chernozems (Calcic Chernozems) in the steppe zone. Under long-term agricultural use (from 1964 to 2014), the content of mobile phosphorus in arable soils of the region under study has increased from 55 to 137 mg/kg, and the content of mobile potassium has increased from 105 to 147 mg/kg. During the period of 1976–2014, the share of acid soils has increased from 22.8 to 45.8%, including medium-acid soils from 1.5 to 12.6%. No significant changes in the weighted average content of soil organic matter are revealed for the period from 1985 to 2014. The value of this parameter is within the range of 4.8–5.0%. In the 2010–2014, 95.0% of arable soils belonged to the category of low supplied with mobile sulfur; 99.2, 96.9, 94.1, and 54.4% of soils were poorly supplied with zinc, copper, cobalt, and manganese, respectively. During the same period, the maximum average productivity of the crop area (3710 f. u./ha) was noted at the application of 4.8 t/ha organic fertilizers and 97.9 kg/ha organic fertilizers on the average. The maximum long-term yields of sugar beet (36.8 t/ha) and corn grain (4.97 t/ha) were obtained at the application of relatively low fertilizer rates.  相似文献   

7.
不同培肥处理对土壤溶解性有机碳含量及特性的影响   总被引:21,自引:0,他引:21  
以黄土高原南部地区的长期肥料定位试验为研究对象,通过室内测定及培养试验研究了不施肥(CK)、撂荒(FA)、施氮磷钾肥(NPK)、氮磷钾配施有机肥(MNPK)和氮磷钾配施秸秆(SNPK)培肥处理土壤中溶解性有机碳(DOC)的含量、结构特性及其降解特性。结果表明,在0~20 cm耕层土壤中,不同培肥处理土壤中DOC的含量变化范围在4.65~8.94 mg kg-1之间,平均为6.42 mg kg-1,各培肥处理间差异明显,其大小顺序为MNPKSNPKNPKFACK。由DOC溶液的UV280吸收值和腐殖化指数(HIXem)可以得出,不同培肥处理土壤中溶解性有机物中结构相对复杂的芳香化合物所占的比例明显不同,其大小顺序为SNPKMNPKFANPKCK。经过7d的生物降解培养,不同培肥处理土壤DOC溶液的降解率变化范围在19.3%~48.5%之间,平均为28.6%,其大小顺序为CKFANPKSNPKMNPK。随着培养的进行,DOC溶液中结构较为复杂的溶解性有机物的比例上升。  相似文献   

8.
Carbonate pedofeatures of three chernozemic soils developed from loesslike loams in the foreststeppe zone of Lipetsk oblast under fallow plot (Luvic Chernozem (Clayic, Pachic)) and under forest (Calcic Chernozem (Clayic, Pachic)) and in the steppe zone of Dnepropetrovsk oblast (Calcic Chernozem (Episiltic, Endoclayic, Pachic)) were studied in the field and laboratory with the use of a set of methods, including the radiocarbon method, mass spectrometry, and micro- and submicromorphology. The morphological diversity of carbonate pedofeatures in these soils was represented by carbonate veins, coatings, disperse carbonates (carbonate impregnations), soft masses (beloglazka), and concretions. In the forest-steppe soils, disperse carbonates and soft masses were absent. The radiocarbon age of carbonate pedofeatures in the forest-steppe soils varied within a relatively narrow range of 3–4.3 ka cal BP with a tendency for a younger age of carbonate concretions subjected to destruction (geodes). In the steppe chernozem, this range was larger, and the 14C ages of different forms of carbonate pedofeatures were different. Thus, soft masses (beloglazka) had the age of 5.5–6 ka cal BP; disperse carbonates, 17.5–18.5 ka cal BP; and hard carbonate concretions, 26–27 ka cal BP. Data on δ13C demonstrated that the isotopic composition of carbon in virtually all the “nonlabile” carbonate pedofeatures does not correspond to the isotopic composition of carbon of the modern soil organic matter. It was shown that the studied chernozemic soils are polygenetic formations containing carbonate pedofeatures of different ages: (a) recent (currently growing), (b) relict, and (c) inherited pedofeatures. The latter group represents complex pedofeatures that include ancient fragments integrated in younger pedofeatures, e.g., the Holocene soft carbonate nodules with inclusions of fragments of the ancient microcodium.  相似文献   

9.
Information about the mineralization rate of compost at various temperatures is a precondition to optimize mineral N fertilization and to minimize N losses in compost‐amended soils. Objectives were to quantify the influence of the temperature on the mineralization rate and leaching of dissolved organic carbon (DOC) and nitrogen (DON), NO3, and NH4+ from a fresh (C : N = 15.4) and a mature (C : N = 9.2) organic household waste compost. Compost samples were mixed with quartz sand to ensure aerobic conditions, incubated at 5, 10, 15, 20, and 25°C and irrigated weekly for 112 days. For the fresh compost, cumulative CO2 evolution after 112 days ranged from 36% of the initial C content at 5°C to 54% at 25°C. The CO2 evolution was only small in the experiments with mature compost (1 to 6% of the initial C content). The data were described satisfactorily by a combined first‐order (fresh compost) or a first‐order kinetic model (mature compost). For the fresh compost, cumulative DOC production was negatively related to the temperature, probably due to leaching of some of the partly metabolized easily degradable fractions at lower temperatures. The production ratios of DOC : CO2‐C decreased with increasing temperature from 0.094 at 5°C to 0.038 at 25°C for the fresh and from 1.55 at 5°C to 0.26 at 25°C for the mature compost. In the experiments with fresh compost, net release of NO3 occurred after a time lag which depended on the temperature. Cumulative net release of NO3 after 112 days ranged from 1.8% of the initial N content at 5°C to 14.3% at 25°C. Approximately 10% of the initial N content of the mature compost was released as NO3 after 14 days at all temperatures. The DOC : DON ratios in the experiments using fresh compost ranged from 11.5 to 15.7 and no temperature dependency was observed. For the mature compost, DOC : DON ratios were slightly smaller (7.4 to 8.9). The DON : (NH4+ + NO3) ratio decreased with increasing temperature from 0.91 at 5°C to 0.19 at 25°C for the fresh compost and from 0.21 at 5°C to 0.12 at 25°C for the mature compost. The results of the dynamics of C and N mineralization of fresh and mature compost can be used to assess the appropriate application (timing and amount) of compost to soils.  相似文献   

10.
Most studies on dissimilatory nitrate reduction to ammonium (DNRA) in paddy soils were conducted in the laboratory and in situ studies are in need for better understanding of the DNRA process.In this study,in situ incubations of soil DNRA using 15 N tracer were carried out in paddy fields under conventional water (CW) and low water (LW) managements to explore the potential of soil DNRA after liquid cattle waste (LCW) application and to investigate the impacts of soil redox potential (Eh) and labile carbon on DNRA.DNRA rates ranged from 3.06 to 10.40 mg N kg 1 dry soil d 1,which accounted for 8.55%-12.36% and 3.88%-25.44% of consumption of added NO 3-15 N when Eh at 5 cm soil depth ranged from 230 to 414 mV and 225 to 65 mV,respectively.DNRA rates showed no significant difference in paddy soils under two water managements although soil Eh and/or dissolved organic carbon (DOC) were more favorable for DNRA in the paddy soil under CW management 1 d before,or 5 and 7 d after LCW application.Soil DNRA rates were negatively correlated with soil Eh (P < 0.05,n=5) but positively correlated with soil DOC (P < 0.05,n=5) in the paddy soil under LW management,while no significant correlations were shown in the paddy soil under CW management.The potential of DNRA measured in situ was consistent with previous laboratory studies;and the controlling factors of DNRA in paddy soils might be different under different water managements,probably due to the presence of different microfloras of DNRA.  相似文献   

11.
Microbial decomposition of extracted and leached dissolved organic carbon (DOC) and nitrogen (DON) was demonstrated from three pasture soils in laboratory incubation studies. DOC concentration in water extracts ranged between 29 and 148 mg C L?1 and DON concentration ranged between 2 and 63 mg N L?1. Between 17 and 61 % of the DOC in the water extracts were respired as CO2 by microbes by day 36. DON concentrations in the extracts declined more rapidly than DOC. Within the first 21 days of incubation, the concentration of DON was near zero without any significant change in the concentration of NO3 ? or NH4 +, indicating that microbes had utilized the organic pool of N preferentially. Decomposition of leached DOC (ranged between 7 and 66 mg C L?1) and DON (ranged between 6 and 11 mg N L?1) collected from large lysimeters (with perennial pasture; 50 cm diameter?×?80 cm deep) followed a similar pattern to that observed with soil extracts. Approximately 28 to 61 % of the DOC in leachates were respired as CO2 by day 49. The concentration of DON in the leachates declined to below 1 mg N L?1 within 7–14 days of the incubation, consistent with the observations made with extractable DON. Our results clearly show that DOC and DON components of the dissolved organic matter in pasture soils, whether extracted or leached, are highly decomposable and bioavailable and will influence local ecosystem functions and nutrient balances in grazed pasture systems and receiving water bodies.  相似文献   

12.
Phosphorus (P) speciation in 21 basaltic and four non-basaltic Irish grassland soils was determined by NaOH–EDTA extraction and 31P NMR spectroscopy. Organic P in basaltic soils ranged between 30 and 697 mg P kg−1 and consisted of phosphate monoesters (84–100%), DNA (0–16%) and phosphonates (0–5%). Inorganic P was mainly phosphate (83–100%) with small concentrations of pyrophosphate (0–17%). Phosphate monoesters were more important as a proportion of extracted P in basaltic soils, probably because of their greater oxalate-extractable Fe and Al contents. Phosphate monoesters appeared to be strongly associated with non-crystalline Al and increased with total soil P concentration, indicating that they do accumulate in grassland soils. In non-basaltic soils myo -inositol hexakisphosphate constituted between 20 and 52% of organic P, while scyllo -inositol hexakisphosphate constituted between 12 and 17%. These compounds were not quantified separately in basaltic soils because of poor NMR resolution in the phosphate monoester region, but appeared to represent a considerable proportion of the organic P in most samples. DNA concentrations were greater in basaltic soils compared with non-basaltic soils and were associated with acidic pH and large total C contents. The inability of the Olsen P test to assess effectively the P status of basaltic soils may result from strong phosphate sorption to Fe and Al oxides, inducing plant utilization of soil organic P. Phosphorus nutrient management should account for this to avoid over-application of P and associated financial and environmental costs.  相似文献   

13.
Composts are considered to be one of the best soil amendments. However, the effects of composts with added polymeric materials on soil physical,hydraulic, and micromorphological properties have not been widely discussed. Changes in soil physical properties influence the numerous services that soils provide. We studied the impacts of composts with the addition of three different polymers(F1–F3) produced from polyethylene and thermoplastic corn starch on the physical, hydraulic, and micromorphological properties of two soils, a Cambic Phaeozem and a Luvic Phaeozem. Applying composts with polymers had limited or no significant effect on soil bulk density and porosity, but increased the field water capacity by 18%–82% and 3%–6% and the plant-available water content by 15%–23% and 4%–17% for the Cambic Phaeozem and Luvic Phaeozem, respectively. The application of composts with polymers had a greater effect on the Cambic Phaeozem than on the Luvic Phaeozem. It was suggested that the use of modified composts led to changes in soil physical properties and micromorphological features and this effect was dependent on the compost application rate. Composts made with the addition of composite synthetic and natural material-derived polymers during composting were found to be a composite mixture that can be successfully used in agriculture.  相似文献   

14.
The amount and composition of rhizo‐deposition as an important component of dissolved organic carbon (DOC) in forest soils is largely unknown. The objective of our study was to examine one component of DOC production in forest soils, namely rhizo‐deposition, under conditions of low, moderate, and high inorganic‐nitrogen (N) input. Two‐year‐old Picea abies saplings were incubated in hydroponic solution for a period of 2 weeks, comprising an adaptation and an experimental period of each 1 week. Treatments included 0 (zero N), 1, 10 (moderate N), and 100 (high N) mg N L–1 nitrogen addition split equally between nitrate and ammonium. Quantity and quality of dissolved‐organic‐carbon (DOC) production were investigated. Cumulative DOC production ranged between 3.7 and 8.8 mg C (g root dry weight)–1 (7 d)–1 and was significantly reduced in zero‐ and high‐N treatments. In turn, the specific UV absorbance as a measure of the aromaticity increased significantly in zero‐ and high‐N treatments, indicating a reduced contribution of microbial products to rhizo‐deposited C. Mineralization of rhizo‐deposited DOC was not significantly different between N treatments at day 1 of the experimental period, but by day 7, 69% of rhizo‐deposition in zero‐N hydroponic solution was mineralizable compared to 37%–49% for the moderate‐ and high‐N treatments. Increasing N input tended to result in decreased degradability. We conclude from this short‐term experiment that rhizo‐deposited DOC from Norway spruce displays a fast response to changes in inorganic N.  相似文献   

15.
根迹土壤根诱导的化学变化对植物吸收重金属的影响   总被引:4,自引:0,他引:4  
K. R. KIM  G. OWENS  R. NAIDU 《土壤圈》2010,20(4):494-504
It is increasingly recognized that metal bioavailability is a better indicator of the potential for phytoremediation than the total metal concentration in soils; therefore, an understanding of the inffuence of phytoremediation plants on metal dynamics at the soil-root interface is increasingly vital for the successful implementation of this remediation technique. In this study, we investigated the heavy metal and soil solution chemical changes at field moisture, after growth of either Indian mustard (Brassica juncea) or sunffower (Helianthus annuus L.), in long-term contaminated soils and the subsequent metal uptake by the selected plants. In addition, the fractions of free metal ions in soil solution were determined using the Donnan membrane technique. After plant growth soil solution pH increased by 0.2-1.4 units and dissolved organic carbon (DOC) increased by 1-99 mg L-1 in all soils examined. Soluble Cd and Zn decreased after Indian mustard growth in all soils examined, and this was attributed to increases in soil solution pH (by 0.9 units) after plant growth. Concentrations of soluble Cu and Pb decreased in acidic soils but increased in alkaline soils. This discrepancy was likely due to a competitive effect between plant-induced pH and DOC changes on the magnitude of metal solubility. The fractions of free Cd and Zn ranged from 7.2% to 32% and 6.4% to 73%, respectively, and they generally decreased as pH and DOC increased after plant growth. Metal uptake by plants was dependant on the soil solution metal concentration, which was governed by changes in pH and DOC induced by plant exudates, rather than on the total metal concentrations. Although plant uptake also varied with metal and soil types, overall soluble metal concentrations in the rhizosphere were mainly inffuenced by root-induced changes in pH and DOC which subsequently affected the metal uptake by plants.  相似文献   

16.
Long‐term monitoring data from eastern North America and Europe indicate a link between increased dissolved organic carbon (DOC) concentrations in surface waters over the last two decades and decreased atmospheric pollutant and marine sulphur (S) deposition. The hypothesis is that decreased acidity and ionic strength associated with declining S deposition has increased the solubility of DOC. However, the sign and magnitude of DOC trends have varied between sites, and in some cases at sites where S deposition has declined, no significant increase in DOC has been observed, creating uncertainty about the causal mechanisms driving the observed trends. In this paper, we demonstrate chemical regulation of DOC release from organic soils in batch experiments caused by changes in acidity and conductivity (measured as a proxy for ionic strength) associated with controlled SO42? additions. DOC release from the top 10 cm of the O‐horizon of organo‐mineral soils and peats decreased by 21–60% in response to additions of 0–437 µeq SO42? l?1 sulphuric acid (H2SO4) and neutral sea‐salt solutions (containing Na+, Mg2+, Cl?, SO42?) over a 20‐hour extraction period. A significant decrease in the proportion of the acid‐sensitive coloured aromatic humic acids (measured by specific ultra‐violet absorbance (SUVA) at 254 nm) was also found with increasing acidity (P < 0.05) in most, but not all, soils, confirming that DOC quality, as well as quantity, changed with SO42? additions. DOC release appeared to be more sensitive to increased acidity than to increased conductivity. By comparing the change in DOC release with bulk soil properties, we found that DOC release from the O‐horizon of organo‐mineral soils and semi‐confined peats, which contained greater exchangeable aluminium (Al) and had lower base saturation (BS), were more sensitive to SO42? additions than DOC release from blanket peats with low concentrations of exchangeable Al and greater BS. Therefore, variation in soil type and acid/base status between sites may partly explain the difference in the magnitude of DOC changes seen at different sites where declines in S deposition have been similar.  相似文献   

17.
Agricultural soil landscapes of hummocky ground moraines are characterized by 3D spatial patterns of soil types that result from profile modifications due to the combined effect of water and tillage erosion. We hypothesize that crops reflect such soil landscape patterns by increased or reduced plant and root growth. Root development may depend on the thickness and vertical sequence of soil horizons as well as on the structural development state of these horizons at different landscape positions. The hypotheses were tested using field data of the root density (RD) and the root lengths (RL) of winter wheat using the minirhizotron technique. We compared data from plots at the CarboZALF‐D site (NE Germany) that are representing a non‐eroded reference soil profile (Albic Luvisol) at a plateau position, a strongly eroded profile at steep slope (Calcaric Regosol), and a depositional profile at the footslope (Anocolluvic Regosol). At each of these plots, three Plexiglas access tubes were installed down to approx. 1.5 m soil depth. Root measurements were carried out during the growing season of winter wheat (September 2014–August 2015) on six dates. The root length density (RLD) and the root biomass density were derived from RD values assuming a mean specific root length of 100 m g?1. Values of RD and RLD were highest for the Anocolluvic Regosol and lowest for the Calcaric Regosol. The maximum root penetration depth was lower in the Anocolluvic Regosol because of a relatively high and fluctuating water table at this landscape position. Results revealed positive relations between below‐ground (root) and above‐ground crop parameters (i.e., leaf area index, plant height, biomass, and yield) for the three soil types. Observed root densities and root lengths in soils at the three landscape positions corroborated the hypothesis that the root system was reflecting erosion‐induced soil profile modifications. Soil landscape position dependent root growth should be considered when attempting to quantify landscape scale water and element balances as well as agricultural productivity.  相似文献   

18.
The recent identification of scyllo-inositol hexakisphosphate in alkaline soil extracts by solution 31P NMR spectroscopy allowed us to investigate this compound in soils by re-analyzing spectra from two previously published studies. Concentrations of scyllo-inositol hexakisphosphate in 29 temperate pasture soils from England and Wales ranged between 11 and 130 mg P kg−1 soil and accounted for between 4 and 15% of the soil organic phosphorus. The ratio of scyllo-inositol hexakisphosphate to myo-inositol hexakisphosphate ranged between 0.29 and 0.79. In a 10 month pot experiment with six grassland soils from New Zealand, growth of pine seedlings (Pinus radiata D. Don) decreased scyllo-inositol hexakisphosphate concentrations by between 10 and 46%. Growth of ryegrass (Lolium perenne L.) decreased scyllo-inositol hexakisphosphate in three low-nutrient soils by 5-21%, but increased it in three other soils by 11-16%. We conclude that scyllo-inositol hexakisphosphate is an important component of soil organic phosphorus with potential ecological significance.  相似文献   

19.

Purpose

Soils that develop on the dumps in historical arsenic mining sites contain high concentrations of As thus constituting a serious environmental risk. This study was aimed to examine the changes in arsenic solubility in mine soils as induced by organic matter introduced with forest litter.

Materials and methods

Four large samples of initially developed soils were collected from the dumps remaining in former mining sites and were incubated for 90 days at various moistures: 80% of maximum water holding capacity and 100% (flooded conditions), with and without addition of beech forest litter (BL), 50 g/kg. Soils contained up to 5.0% As. Soil pore water was collected periodically with MacroRhizon suction samplers and examined on As, Mn, and Fe concentrations, pH, Eh, and dissolved organic carbon (DOC). The properties of dissolved organic matter were characterized by UV-VIS spectroscopic parameters A4/A6 and SUVA254.

Results and discussion

Application of BL resulted in an intensive release of As from soils, particularly at 100% moisture. As concentrations in soil pore water increased strongly during the first 2 or 4 weeks of incubation and then started to decrease in all cases, except for one flooded soil. As was released particularly intensively from carbonate-containing soils. The mechanisms of As mobilization, including reductive dissolution of Mn and Fe oxides and the competition with DOC for sorption sites on the oxides, were discussed as related to soil properties. Pore water concentrations of DOC were increasing at the beginning of incubation and started to decrease after two or four weeks. Spectroscopic parameters of dissolved organic matter in ZS soils indicated increasing aromaticity and progress of humification.

Conclusions

Forest litter introduced to mine dump soils causes a mobilization of As into soil pore water. This effect, particularly strong in carbonate-rich soils, is apparently related to high concentrations of DOC and usually declines with time, which may be explained by the progress in humification. The relationships between DOC properties and As speciation in soil pore water should be dissected for better interpretation of experimental results.
  相似文献   

20.
Data on the dynamics of the temperature and moisture of four soils in a catena (Luvisol, calcaric Regosol, gleyic-calcaric Regosol, and Anthrosol) in the western Kraichgau region (Germany) were analyzed. The statistical processing of the data involved methods of time series analysis, including Census I decomposition, as well as analysis of variance (ANOVA) for repeated measurements using SAS PROC MIXED. From the ANOVA results, a reliable difference in the average values of the soil temperature and moisture was revealed, as well as the amplitudes of their annual variations. The highest dynamics of the parameters studied were typical for the calcaric Regosol.  相似文献   

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