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1.
Vincenzo Bagarello Vito Ferro Vincenzo Pampalone Paolo Porto Francesca Todisco Lorenzo Vergni 《Journal of Soils and Sediments》2018,18(12):3365-3377
Purpose
The USLE-MM estimates event normalized plot soil loss, Ae,N, by an erosivity term given by the runoff coefficient, QR, times the single-storm erosion index, EI30, raised to an exponent b1?>?1. This modeling scheme is based on an expected power relationship, with an exponent greater than one, between event sediment concentration, Ce, and the EI30/Pe (Pe = rainfall depth) term. In this investigation, carried out at the three experimental sites of Bagnara, Masse, and Sparacia, in Italy; the soundness of the USLE-MM scheme was tested.Materials and methods
A total of 1192 (Ae,N, QREI30) data pairs were used to parameterize the model both locally and considering all sites simultaneously. The performances of the fitted models were established by considering all erosive events and also by distinguishing between events of different severity.Results and discussion
The b1 exponent varied widely among the three sites (1.05–1.44) but using a common exponent (1.18) for these sites was possible. The Ae,N prediction accuracy increased in the passage from the smallest erosion events (Ae,N?≤?1 Mg ha?1, median error =?3.35) to the largest ones (Ae,N?>?10 Mg ha?1, median error =?1.72). The QREI30 term was found to be usable to predict both Ae,N and the expected maximum uncertainty of this prediction. Soil erodibility was found to be mainly controlled by the largest erosion events.Conclusions
Development of a single USLE-MM model appears possible. Sampling other sites is advisable to develop a single USLE-MM model for a general use.2.
Purpose
Soil microbes contribute significantly to soil respiration (SR) in boreal forests; however, there is limited knowledge on microbial contributions from long field investigations. The objective of this study was to estimate soil microbial respiration, as well as its primary controlling factors, for a period of three consecutive years.Materials and methods
A trenching method was used to distinguish soil microbial respiration (R Mic) in a 55-year-old mature Japanese larch (Larix kaempferi) plantation in Northern Japan; the soil in which developed originally from volcanic soils containing pumice. We used a portable CO2 detection system to measure the soil respiration rate during the growing season. Environmental factors, soil physiochemical characteristics, and soil microbial biomass carbon and nitrogen (MBC and MBN) were analyzed to explain the seasonal variations of SR and R Mic.Results and discussion
The results showed that the estimated contribution of soil microbes to SR was 78, 62, and 55% during the three successive years, respectively. Respiration attributable to decomposition of aboveground litter contributed approximately 19% to SR. The major environmental factor that affected R Mic was soil temperature at 5 cm depth, which accounted for more than 70% of the seasonal variation in R Mic observed. There were close relations among MBC, MBN, and soil water content, but the soil water content showed no significant relation with R Mic.Conclusions
The R Mic to SR varied from 78 to 55% following 3 years of trenching treatments. Our results demonstrated the important role of soil microbes on soil respiration in this larch forest. Soil temperature was the major positive factor that influenced R Mic, while soil water content had no significant effect. Global warming will increase the loss of C into the atmosphere by increasing the R Mic, and could accelerate climate change.3.
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.4.
Peng Su Jun Lou Philip C. Brookes Yu Luo Yan He Jianming Xu 《Journal of Soils and Sediments》2017,17(3):674-684
Purpose
This work investigated changes in priming effects and the taxonomy of soil microbial communities after being amended with plant feedstock and its corresponding biochar.Materials and methods
A soil incubation was conducted for 180 days to monitor the mineralization and evolution of soil-primed C after addition of maize and its biochar pyrolysed at 450 °C. Responses of individual microbial taxa were identified and compared using the next-generation sequencing method.Results and discussion
Cumulative CO2 showed similar trends but different magnitudes in soil supplied with feedstock and its biochar. Feedstock addition resulted in a positive priming effect of 1999 mg C kg?1 soil (+253.7 %) while biochar gave negative primed C of ?872.1 mg C kg?1 soil (?254.3 %). Linear relationships between mineralized material and mineralized soil C were detected. Most priming occurred in the first 15 days, indicating co-metabolism. Differences in priming may be explained by differences in properties of plant material, especially the water-extractable organic C. Predominant phyla were affiliated to Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Firmicutes, Planctomycetes, Proteobacteria, Verrucomicrobia, Ascomycota, Basidiomycota, Blastocladiomycota, Chytridiomycota, Zygomycota, Euryarchaeota, and Thaumarchaeota during decomposition. Cluster analysis resulted in separate phylogenetic grouping of feedstock and biochar. Bacteria (Acidobacteria, Firmicutes, Gemmatimonadetes, Planctomycetes), fungi (Ascomycota), and archaea (Euryarchaeota) were closely correlated to primed soil C (R 2?=??0.98, ?0.99, 0.84, 0.81, 0.91, and 0.91, respectively).Conclusions
Quality of plant materials (especially labile C) shifted microbial community (specific microbial taxa) responses, resulting in a distinctive priming intensity, giving a better understanding of the functional role of soil microbial community as an important driver of priming effect.5.
Heterotrophic soil respiration (R H) and autotrophic soil respiration (R A) by a trenching method were monitored in four vegetation types in subtropical China from November 2011 to October 2012. The four vegetation types included a shrubland, a mixed-conifer, a mixed-legume, and a mixed-native species. The average R H was significantly greater in soils under the mixed-legume and the mixed-native species than in the shrubland and the mixed-conifer soils, and it affected the pattern of soil total respiration (R S) of the four soils. The change in R H was closely related to the variations of soil organic C, total N and P content, and microbial biomass C. The R A and the percentage of R S respired as R A were only significantly increased by the mixed-native species after reforestation. Probably, this depended on the highest fine root biomass of mixed-native species than the other vegetation types. Soil respiration sources were differently influenced by the reforestation due to different changes in soil chemical and biological properties and root biomass. 相似文献
6.
Zhenghui Cui Hongwei Fang Lei Huang Ke Ni Danny Reible 《Journal of Soils and Sediments》2017,17(12):2887-2898
Purpose
Adsorptive interaction at the solid-water interface plays an important role in the fate and behavior of phosphorus (P) in rivers and lakes and the resulting eutrophication. This study aims to investigate the contributions of heterogeneous morphology to P adsorption onto mineral particles.Materials and methods
The dominant minerals in Yellow River sediment, quartz, k-feldspar, and calcite are investigated with adsorption experiments and microscopic examinations. Taylor expansion is applied to quantitatively characterize the heterogeneous surface morphology.Results and discussion
The results reveal that locally concave or convex micro-morphology characterized by the second derivative term of the Taylor expansion, F 2, can be related to adsorption capacity due to its effect on surface-charge density and distribution. The distribution of adsorbed P as a function of F 2 was determined for selected particles composed of each of the pure minerals and was fit to a Weibull distribution. Each mineral was characterized by F 2a , the weighted average value of F 2, and Weibull distribution factors, and correlated with sorption isotherms. The developed relationships were used to accurately predict adsorption onto individual particles as well as pure mineral samples.Conclusions
Mineral particles have complex surface morphology, which affects the interface P adsorption. Micro-morphological characterization of F 2 and F 2a can be used to predict adsorption onto the pure minerals, and this study provides physical basis for predicting adsorption on sediment particles composed of these minerals.7.
Kobra Mahdavian Seyed Majid Ghaderian Masoud Torkzadeh-Mahani 《Journal of Soils and Sediments》2017,17(5):1310-1320
Purpose
This study investigated the extent of metal accumulation by plants colonizing a mining area in Yazd Province in Central Iran. It also investigated the suitability of these plants for phytoextraction and phytostabilization as two potential phytoremediation strategies.Materials and methods
Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization, whereas plants with both BCFs and TFs >1 may be appropriate for phytoextraction. In this study, both shoots and roots of 40 plant species and associated soil samples were collected and analyzed for total concentrations of trace elements (Pb, Zn, and Ag). BCFs and TFs were calculated for each element.Results and discussion
Nonnea persica, Achillea wilhelmsii, Erodium cicutarium, and Mentha longifolia were found to be the most suitable species for phytostabilization of Pb and Zn. Colchicum schimperi, Londesia eriantha, Lallemantia royleana, Bromus tectorum, Hordeum glaucum, and Thuspeinantha persica are the most promising species for element phytoextraction in sites slightly enriched by Ag. Ferula assa-foetida is the most suitable species for phytostabilization of the three studied metals. C. schimperi, L. eriantha, L. royleana, B. tectorum, M. longifolia, and T. persica accumulated Ag, albeit at low level.Conclusions
Our preliminary study shows that some native plant species growing on this contaminated site may have potential for phytoremediation.8.
Anna M. Stefanowicz Marta L. Majewska Małgorzata Stanek Marcin Nobis Szymon Zubek 《Journal of Soils and Sediments》2018,18(4):1409-1423
Purpose
This study compared the effects of four invasive plants, namely Impatiens glandulifera, Reynoutria japonica, Rudbeckia laciniata, and Solidago gigantea, as well as two native species—Artemisia vulgaris, Phalaris arundinacea, and their mixture on soil physicochemical properties in a pot experiment.Materials and methods
Plants were planted in pots in two loamy sand soils. The soils were collected from fallows located outside (fallow soil) and within river valley (valley soil) under native plant communities. Aboveground plant biomass, cover, and soil physicochemical properties such as nutrient concentrations, pH, and water holding capacity (WHC) were measured after two growing seasons. Discriminant analysis (DA) was used to identify soil variables responsible for the discrimination between plant treatments. Identified variables were further compared between treatments using one-way ANOVA followed by Tukey’s HSD test.Results and discussion
Plant biomass, cover, and soil parameters depended on species and soil type. DA effectively separated soils under different plant species. DA on fallow soil data separated R. laciniata from all other treatments, especially I. glandulifera, native species and bare soil, along axis 1 (related mainly to exchangeable K, N-NH4, total P, N-NO3, and WHC). Large differences were found between R. laciniata and S. gigantea as indicated by axis 2 (S-SO4, exchangeable Mg, total P, exchangeable Ca, and total Mg). DA on valley soil data separated R. japonica from all other treatments, particularly S. gigantea, R. laciniata, and native mixture, along axis 1 (N-NO3, total N, S-SO4, total P, pH). Along axis 2 (N-NO3, N-NH4, Olsen P, exchangeable K, WHC), large differences were observed between I. glandulifera and all other invaders.Conclusions
Plant influence on soil differed both among invasive species and between invasive and native species. Impatiens glandulifera had a relatively weak effect and its soil was similar to both native and bare soils. Multidirectional effects of different invaders resulted in a considerable divergence in soil characteristics. Invasion-driven changes in the soil environment may trigger feedbacks that stabilize or accelerate invasion and hinder re-colonization by native vegetation, which has implications for the restoration of invaded habitats.9.
Li -Juan Chen Qi Feng Yong-Ping Wei Chang-Sheng Li Yan Zhao Hui-Ya Li Bao-Gui Zhang 《Journal of Soils and Sediments》2017,17(2):376-383
Purpose
Irrigation and fertilization can change soil environment, which thereby influence soil microbial metabolic activity (MMA). How to alleviate the adverse effects by taking judicious saline water irrigation and fertilization regimes is mainly concerned in this research.Materials and methods
Here, we conducted a field orthogonal designed test under different saline water irrigation amount, water salinity, and nitrogen fertilizer application. The metabolic profiles of soil microbial communities were analyzed by using the Biolog method.Results and discussion
The results demonstrated that irrigation amount and fertilizer application could significantly change MMA while irrigation water salinity had no significant effect on it. Medium irrigation amount (30 mm), least (50 kg ha?1) or medium (350 kg ha?1) N fertilizer application, and whatever irrigation water salinity could obtain the optimal MMA. Different utilization rates of carbohydrates, amino acids, carboxylic acids, and polymers by soil microbial communities caused the differences of the effects, and D-galactonic acid γ-lactone, L-arginine, L-asparagine, D-glucosaminic acid, Tween 80, L-threonine, and D-galacturonic acid were the indicator for distinguishing the effects.Conclusions
The results presented here demonstrated that by regulating irrigation water amount and fertilizer application, the effects of irrigation salinity on MMA could be alleviated, which offered an efficient approach for guiding saline water irrigation.10.
Ana M. García-López Ramiro Recena Manuel Avilés Antonio Delgado 《Journal of Soils and Sediments》2018,18(3):727-738
Purpose
The effect on P uptake by plants after inoculation with P-mobilizing microorganisms may be modulated by soil properties, including natural microbiota. However, to put this theory into practical use, research is needed to shed new light on the soil factors which affect the capability of improving P nutrition in plants. The aim of this study was to assess how two P-mobilizing microorganisms, Trichoderma asperellum T34 and Bacillus subtilis QST713, influence P uptake by wheat plants in different soils; this will allow us to identify the soil properties which affect the efficiency of P nutrition in plants.Materials and methods
In a completely randomized experiment, wheat was grown in pots in a growing chamber in soils with Olsen P values ranging from 4.8 to 8.7 mg kg?1. The plants were inoculated with three treatments: T34, B. subtilis, and a non-inoculated control.Results and discussion
Overall, B. subtilis was more effective in increasing plant P uptake and in mobilizing soil P (measured as Olsen P values) than T34. In some soils, B. subtilis was the only treatment which increased Olsen P in the rhizosphere after cultivation. However, the effect of both microorganisms differed depending on the soil. For B. subtilis, phytase hydrolysable P, Olsen P, carbonates, the Feca/Fecbd ratio, and citrate-soluble P accounted for 92% of the variation in P uptake in inoculated plants (compared with the non-inoculated control). Most of these soil properties also accounted for 87% of the variation in the levels of shoot dry matter (DM) in B. subtilis-inoculated plants compared with shoot DM in the control plants. In addition, Olsen P, the Feca/Fecbd ratio, and phytase hydrolysable P in the NaOH extracts accounted for 82 and 74% of the variation in the effect of T34 on P uptake and shoot DM, respectively. Overall, the lower the initial Olsen P in the soil, the higher the P uptake caused by microorganisms.Conclusions
The initial availability of P and organic P in soil, in addition to other properties affecting P dynamics in the soil, may explain the triggering and efficiency of the P-mobilizing mechanisms in microorganisms. These are crucial in explaining the potential benefits to crops and, as a result, their practical use as a bio-fertilizer.11.
Yaling Zhang Hong Chen Shahla Hosseini Bai Carl Menke Manyun Zhang Zhihong Xu 《Journal of Soils and Sediments》2017,17(10):2400-2409
Purpose
This study aimed to assess the effects of biochar on improving nitrogen (N) pools in mine spoil and examine the effects of elevated CO2 on soil carbon (C) storage.Materials and methods
The experiment consisted of three plant species (Austrostipa ramossissima, Dichelachne micrantha, and Lomandra longifolia) planted in the N-poor mine spoil with application of biochar produced at three temperatures (650, 750, and 850 °C) under both ambient (400 μL L?1) and elevated (700 μL L?1) CO2. We assessed mine spoil total C and N concentrations and stable C and N isotope compositions (δ13C and δ15N), as well as hot water extractable organic C (HWEOC) and total N (HWETN) concentrations.Results and discussion
Soil total N significantly increased following biochar application across all species. Elevated CO2 induced soil C loss for A. ramossissima and D. micrantha without biochar application and D. micrantha with the application of biochar produced at 750 °C. In contrast, elevated CO2 exhibited no significant effect on soil total C for A. littoralis, D. micrantha, or L. longifolia under any other biochar treatments.Conclusions
Biochar application is a promising means to improve N retention and thus, reduce environmentally harmful N fluxes in mine spoil. However, elevated CO2 exhibited no significant effects on increasing soil total C, which indicated that mine spoil has limited potential to store rising atmospheric CO2.12.
Yaling Zhang Carl Menke Barbara Drigo Shahla Hosseini Bai Ian Anderson Zhihong Xu Hong Chen Manyun Zhang 《Journal of Soils and Sediments》2017,17(10):2410-2419
Purpose
Re-establishment of soil nitrogen (N) capital is a priority in mine rehabilitation. We aimed to evaluate the effects of biochar addition on improving mine spoil N pools and the influence of elevated CO2 concentration on mine rehabilitation.Materials and methods
We assessed the effects of pinewood biochar, produced at three temperatures (650, 750 and 850 °C, referred as B650, B750 and B850, respectively), on mine spoil total N concentrations with five different plant species, including a tree species (Eucalyptus crebra), N-fixing shrubs (Acacia floribunda and Allocasuarina littoralis) and C3 and C4 grasses (Austrodanthonia tenuior and Themeda australis) incubated at ambient (400 μL L?1) and elevated (700 μL L?1) atmospheric CO2 concentrations, as well as the effects of elevated CO2 on mine rehabilitation.Results and discussion
Soil total N significantly improved following biochar incorporation under all plant species (P < 0.05) except for T. Australis. E. crebra had the highest soil total N (0.197%, 0.198% and 0.212% for B650, B750 and B850, respectively). Different from the negligible influence of elevated CO2 on soil properties under the grasses and the N-fixing shrubs, elevated CO2 significantly increased soil water and hot water extractable organic C (WEOC and HWEOC, respectively) and decreased total C under E. crebra, indicating that the nutrient demands were not met.Conclusions
Biochar addition showed the potential in mine rehabilitation in terms of improving soil N pool, especially with E. crebra. However, it would be more difficulty to rehabilitate mine spoils in future with the rising atmospheric CO2 concentration.13.
Qiang Feng Wenwu Zhao Jingyi Ding Xuening Fang Xiao Zhang 《Journal of Soils and Sediments》2018,18(3):775-790
Purpose
We attempt to describe the cover and management (C) factor more comprehensively through the use of a simple and efficient method.Materials and methods
We measure the coverage of each vegetation layer and C factor for 152 sampled plots in the Ansai watershed. We propose four stratified coverage indices (green coverage (V G), total coverage (V T), probability coverage (V P), weight coverage (V W)), derive green and yellow vegetation indices from Landsat 8 OLI images to reflect green and residue cover, and construct and validate C factor estimation models from stratified coverage and remote sensing indices, respectively.Results and discussion
(1) V T and V P present C factor estimation advantages for grassland and shrub land. V W can better illustrate the C factor due to the relatively complete spatial structuring of woodland and orchard land. For cropland, four stratified coverage indices present the same estimation capacities for the C factor. Except for cropland and grassland, the estimation capabilities of V G are relatively low because the residue layer is ignored. (2) The C factor is more sensitive to yellow vegetation indices, which indicates that senescent fractional cover and litter are important and cannot be ignored. The linear and non-linear models can explain 56.6 and 61.8% of C factor variation, respectively, and the linear model is more accurate than the non-linear model. (3) Compared to traditional indices (projective coverage and single remote sensing indices), stratified coverage indices and a combination of several remote sensing indices can estimate the C factor more effectively.Conclusions
At the field scale, the C value estimation model can be selected according to the land-use type. At the watershed and regional scales, a linear model is recommended for C factor estimation.14.
Isabel Párraga-Aguado Pedro Alcoba-Gómez Héctor M. Conesa 《Journal of Soils and Sediments》2017,17(10):2469-2480
Purpose
The use of municipal solid wastes (MSWs) as a low-cost source of organic matter for soils should be considered after discarding the environmental risks related to their metal(loid) load. The goal of this work was to assess the employment of a MSW as an organic amendment in two types of soil (an agricultural soil, A, and a metal(loid)-enriched mine tailings soil, T) attending to changes in soil properties and in plant growth, nutrition and metal(loid) translocation from roots to aerial parts of Zea mays L. (stalk, leaves, tassel, husk, cob and kernel).Materials and methods
After a comprehensive characterisation of each soil treatment (A, A + MSW, T, T + MSW), a pot-designed experiment was carried out. Soil solution was monthly monitored throughout the experiment, and metal(loid) concentrations were measured.Results and discussion
The MSW improved some fertility-related parameters in both soils, A and T: increased total and dissolved organic carbon, total nitrogen and soil microbiology. However, an increase in 0.01 M CaCl2-extractable metal(loid) concentration was also observed. No differences in dry biomass were found between amended and not amended treatments. A fractionation of metal(loid) concentrations among plant organs occurred. For instance, the highest Cu and Pb concentrations were found in roots, while for Zn occurred in the stalk and the cob. The amended treatments favoured the accumulation of Mn in all plant organs. Kernels showed in general the lowest metal(loid) concentrations.Conclusions
The addition of municipal solid wastes as organic amendment could be a suitable tool to increase soil fertility. However, due to the high metal(loid) content of this particular MSW, its use on agricultural soils would not be appropriate. By other hand, along with the improvement of soil fertility, the MSW was useful to promote plant development in the mine tailings soil which should be then considered as a potential tool to promote plant establishment in those metal(loid)-impacted soils.15.
Pernilla Carlsson Jaromír Literák Ladislav Dušek Jakub Hofman Thomas D. Bucheli Jana Klánová 《Journal of Soils and Sediments》2016,16(6):1718-1726
Purpose
The scope of this article was to investigate the spatial and temporal variability of enantiomeric fractions (EFs) of persistent organic pollutants (POPs) in soil compared to the uncertainty of the analytical data.Materials and methods
Soil samples were taken with high spatial resolution at two sites in Czech Republic in 2008 to investigate variability on a small spatial scale. In addition, composite soil samples were taken from ten sites in 2005 and 2008 to investigate temporal variations. All samples were analysed for a suite of soil properties as well as concentrations and EFs of polychlorinated biphenyl (PCB) -95, PCB-132 and PCB-149; α-hexachlorocyclohexane (HCH); o,p′-dichlorodiphenyltrichloroethane (DDT); and o,p′-dichlorodiphenyldichloroethane (DDD).Results and discussion
Median EFs of PCB-95 and PCB-149, α-HCH, o,p′-DDT and o,p′-DDD did not change significantly on the sites sampled in 2005 and again in 2008, while PCB-132 changed from EF?=?0.38 to EF?=?0.53. The sampling methodology is therefore very important, and composite samples will not be the best option if enantioselective degradation processes are investigated. Non-racemic EFs of POPs in the subsampled sites in 2008 were correlated to soil parameters, such as total organic carbon (TOC), total nitrogen and humic acids. These parameters are site specific and might vary on a small scale. This can explain why certain soil parameters are reported as significantly correlated with non-racemic EFs of chiral POPs in some studies, but not always in other similar studies.Conclusions
While composite samples may still represent the overall prevailing EF range, they are not ideally suited to study enantiomeric degradation processes, which are taking place at a relative small scale, depending on the heterogeneity of soil parameters such as TOC, total organic nitrogen (TON) and humic acids.16.
Mohammad Wahsha Mandana Nadimi-Goki Claudio Bini 《Journal of Soils and Sediments》2016,16(4):1300-1305
Purpose
The present paper concerns the distribution and mobility of heavy metals (Cu, Pb, Zn and Fe) in the soils of some abandoned mine sites in Italy and their transfer to wild flora.Materials and methods
Soils and plants were sampled from mixed sulphide mine dumps in different parts of Italy, and the concentrations of heavy metals were determined.Results and discussion
The phytoremediation ability of Salix species (Salix eleagnos, Salix purpurea and Salix caprea), Taraxacum officinale and P?lantago major for heavy metals and, in particular, zinc was estimated. The results showed that soils affected by mining activities presented total Zn, Cu, Pb and Fe concentrations above the internationally recommended permissible limits. A highly significant correlation occurred between metal concentrations in soils.Conclusions
The obtained results confirmed the environmental effects of mine waste; exploring wild flora ability to absorb metals, besides metal exploitation, proved a useful tool for planning possible remediation projects.17.
Marina Rafiq Muhammad Shahid Saliha Shamshad Sana Khalid Nabeel Khan Niazi Ghulam Abbas Muhammad Farhan Saeed Mazhar Ali Behzad Murtaza 《Journal of Soils and Sediments》2018,18(6):2271-2281
Purpose
This study delineated the effect of calcium (Ca) and ethylenediaminetetraacetic acid (EDTA) addition on arsenic (As) accumulation and physiological attributes of Vicia faba L.Materials and methods
Two separate experiments were performed. In the first experiment, V. faba seedlings, grown under hydroponic conditions, were exposed to three levels of As (25, 125 and 250 μM) in the presence and absence of three levels of EDTA (25, 125, 250 μM) and calcium (CaCl2: 1, 5 and 10 mM). The effect of EDTA and Ca on As accumulation and physiological attributes of V. faba was assessed by determining As contents in roots and shoot, chlorophyll contents, H2O2 contents, and lipid peroxidation in young and old leaves. In the second experiment, V. faba seeds were grown in As-contaminated sand culture using the same treatment plan.Results and discussion
The accumulation and toxicity of As to V. faba plants increased with increasing As levels in nutrient solution. Arsenic exposure enhanced the production of reactive oxygen species (ROS) in both roots and leaves, which resulted in lipid peroxidation and decreased chlorophyll contents. The presence of both EDTA and Ca, in general, significantly decreased As accumulation by V. faba seedlings, Ca being more effective than EDTA. Both the amendments decreased As-induced reactive oxygen species (ROS) production and lipid peroxidation. In the case of chlorophyll contents, EDTA significantly decreased chlorophyll contents, while Ca significantly increased chlorophyll contents compared to As. The effect of all the treatments was more pronounced in roots than leaves and in young leaves compared to old leaves.Conclusions
It is proposed that EDTA and Ca greatly affect As accumulation and toxicity to V. faba, and the effect varies greatly with their applied levels as well as type and age of plant organs. The germinating seedlings of V. faba may be preferred for risk assessment studies, while transplanting 1-week-old V. faba seedlings to As-contaminated soils can decrease its toxicity.18.
Junqiang Zheng Yuzhe Wang Nan Hui Haibo Dong Chengrong Chen Shijie Han Zhihong Xu 《Journal of Soils and Sediments》2017,17(4):949-959
Purpose
Our aim was to examine linkages between mass loss, chemical transformation and CH4 production during decomposition of leaf litters submerged under water. We hypothesised that (i) labile leaf litters would fuel a rapid, high rate of methane (CH4) production and that recalcitrant litters would fuel long-lasting but lower emissions, (ii) leaf litters experiencing a greater alteration to chemical properties would stimulate increased CH4 production and (iii) nitrogen (N) addition would increase CH4 emissions.Materials and methods
Litters from six plant species were collected from a riparian ecosystem adjacent to Wyaralong Dam, located in Queensland, Australia, i.e., Lophostemon confertus, Cynodon dactylon, Heteropogon contortus, Chamaecrista rotundifolia, Chrysocephalum apiculatum and Imperata cylindrica. We evaluated the rate of mass loss and CH4 emissions for 122 days of incubation in inundated microcosms with and without N addition. We quantified the chemical changes in the decomposing litters with 13 C-cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectrum.Results and discussion
The inundation treatment of plant litters significantly affected decomposition rates. All litters decomposed in either inundated or aerobic microcosms were quite distinct with regard to the NMR spectra of their initial litters. N addition altered the NMR spectra under both inundation and aerobic conditions. The N treatment only marginally influenced the decomposition rates of I. cylindrica and C. apiculatum litters. The diurnal patterns of CH4 production in the H. contortus, C. rotundifolia and C. apiculatum litters under inundation incubation could be expressed as one-humped curves, with the peak value dependent on litter species and N treatment. N addition stimulated CH4 emission by C. rotundifolia and C. apiculatum litters and inhibited CH4 emission from microcosms containing the litters of the three gramineous species, i.e., I. cylindrica, C. dactylon and H. contortus.Conclusions
Our results provide evidence that labile leaf litters could fuel a rapid, high rate of CH4 production and that recalcitrant litters fuelled a lower CH4 emission. We did not find that leaf litters with altered chemical properties stimulated increased CH4 production. We also found that N addition was able to increase CH4 emissions, but this effect was dependent on the litter species.19.