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1.
Phytoremediation is a developing technology that uses plants to clean up pollutants in soils. To adopt this technology to cadmium (Cd)–contaminated soils efficiently, a Cd hyperaccumulator with fast growth rate and large biomass is required. In the present study, we selected Caryophyllales as a potential clade that might include Cd hyperaccumulators because this clade had a high mean concentration of zinc (Zn), which is in the same element group as Cd. Three species in Caryophyllales and three species in different clades were grown with Cd. Among them, Amaranthus tricolor showed high accumulating ability for Cd under both water‐culture and soil‐culture conditions, whereas Brassica juncea, a known Cd hyperaccumulator, accumulated high concentrations of Cd in shoots only under water‐culture conditions. This result suggests that A. tricolor has Cd‐solubilizing ability in rhizosphere. Because A. tricolor has large biomass and high growth rate, this species could be useful for phytoremediation of Cd‐contaminated fields.  相似文献   

2.
The increasing number of degraded soil areas caused by open cast mining activities has brought about a critical damage to the environment. The mine spoil must be ameliorated with anthropogenic interferences which consist of revegetating soils after organic matter amendment and provision of microbial diversity, to guarantee basic conditions for a sustainable soil biological activity. Five woody species, Acacia mangium Willd., Inga edulis Mart., Mimosa caesalpiniaefolia Benth, Parkia multijuga Benth., and Schinus terebinthifolia Schlecht. & Cham were cultivated under greenhouse conditions to evaluate the potential of plant establishment on cassiterite mining waste, considering the contribution of mycorrhizal fungi inoculation, organic compost, and thermophosphate amendment. The shoot height, dry weight, and nitrogen and phosphorus shoot contents were determined. Three species of nodulating legumes, A. mangium, M. caesalpiniaefolia, and S. terebinthifolia showed a great positive response to organic compost, termophosphate, and mycorrhizal inoculation, increasing the plant height and the shoot dry weight. Plants inoculated with arbuscular mycorrhizal fungi and fertilized with organic compost also increased their nitrogen and phosphorus shoot contents. The addition of organic compost and mycorrhizal fungi were essential for plant development and the reforestation of mining areas should be initiated with mycotrophic and nodulating legumes.  相似文献   

3.
Abstract

Winter wheat shoot weight and phosphorus (P) concentrations, corn leaf weight and P concentrations, and soil AL, Olsen, H2O, Bray 1, Pi (Fe-oxide impregnated paper strip) and AERM (anion exchange resin membrane) contents were determined in a network of uniform Hungarian national long‐term field trials. P application had a significant effect on soil P test values at different P levels and sites. The relationship between the different soil P test methods was studied separately for different soil groups (all, acid, and calcareous soils). Corn leaf weight was influenced by the sites much more than by soil P supply level, whereas corn leaf P percentage was influenced by both sites and P levels. For winter wheat, both sites and soil P levels had a positive effect on wheat shoot weight. Wheat shoot P percentage was influenced by the soil P supply much more than by the sites. Correlation between corn leaf P percentage and the Pi or AERM extractable P and between wheat shoot P percentage and the Pi and AERM P values was logarithmic.  相似文献   

4.
Abstract

Spatial variability of soil nutrients is known to exist at distances of less than 1 m. Recently, an on‐the‐go system for application of nitrogen (N) fertilizer based on spectral measurements known as in‐season estimated yield (INSEY) improved N use efficiency (NUE) by as much as 17% in winter wheat. Six trials were conducted in 2001, 2002, and 2003 at Ardmore and Burneyville, OK, with an objective to develop an index similar to INSEY for use in predicting yield potential in bermudagrass (Cynodon dactylon L.) that can be used for adjusting fertilizer N rates. Initial results indicate that 55% of variation in predicted bermudagrass forage yield was explained by a Bermudagrass–INSEY (B‐INSEY) index and 54% of the variation in forage N uptake was explained using the normalized difference vegetative index (NDVI). The remaining challenge is to develop appropriate N fertilizer rates based on this information and apply these rates using on‐the‐go technology.  相似文献   

5.
Gaseous phosphine (PH3) in the inshore atmosphere was observed from October 2005 to August 2006 at a coastal site of the Yellow Sea in China. The concentration of PH3 ranged from 0.01 to 14.86 ng m?3 with an average of 1.14 ng m?3. The concentration showed a diurnal variation in PH3 with the peak occurring at morning and the lowest point at noon. An obvious seasonal variation of atmospheric PH3 was found, with the PH3 levels in the summer higher than those in the winter. The PH3 levels in the atmosphere were apparently affected by temperature, radiation, sources, and other meteorological factors. The data indicate that PH3 can be transported between the terrestrial and inshore atmosphere of Qingdao and the Yellow Sea or the East China Sea in both directions. The study increases evidence that PH3 participates within the global biogeochemical phosphorus cycle in P transport from land and inshore waters to the sea where commonly P is scarce and where PH3 inflow could be of important.  相似文献   

6.
Eurasian Soil Science - Data on concentrations and distribution of tritium in soils of the “Atomic” Lake excavation explosion area of Semipalatinsk Nuclear Test Site (Kazakhstan, East...  相似文献   

7.
Erosion and transport of soil has worldwide implications for agriculture, landscape stability, climate, natural hazards, and clean, renewable resources of water and air. Assured access to clean water and a healthy and safe environment requires an ethic of conservation and protection. The minimum scale in which these principles apply successfully is basin wide. These are the fundamental concerns of the Sino-US Centers for Soil and Water Conservation and Environmental Protection.  相似文献   

8.
This study examines the synoptic conditions controlling NO x pollution in the metropolitan area of Tel Aviv, using a semi-objective synoptic classification for the eastern Mediterranean. A day in which NO x concentration exceeded the Israeli standard in ≥1 of the seven monitoring stations was defined an “exceeding day” and in ≥5 as an “extensive exceeding day”. For 1998–2004, 19% and 3% of the days were found exceeding and extensive exceeding days, respectively, over 85% of them in the winter months, November–March. The inter-annual variation in the occurrence of the synoptic types was found to explain 72% of the variations in the number of exceeding days. A significant negative trend in the occurrence of types with high pollution potential explained the decrease of 10% per year in the number of exceeding days during 1998–2004. The Red Sea Trough, though being cyclonic system, contributed 51% of the exceeding days, while highs, though being more frequent, contributed only 35%. The “pollution potential” of a synoptic type was defined as the percentage of exceeding days belonging to this type. The majority of synoptic types with the highest pollution potential were cyclonic, most being the Red Sea Trough with western axis, with 82% potential. Our findings indicate that the identity of the synoptic system as cyclonic or anticyclonic is not the key factor for the pollution potential in the study region, but rather, the ambient atmospheric conditions they induce, i.e., high temperatures, static stability, and weak easterly offshore flow. Local processes are the direct cause of the pollution and that the role of the synoptic conditions is to enable, or even to reinforce, the supportive meso-scale processes. This study is a first step in downscaling synoptic features to local NO x pollution potential, constituting a basis for alarming against pollution events, based on the predicted synoptic conditions.  相似文献   

9.
Several coagulants/flocculants have been studied in order to remove the color and turbidity of raw water, employing natural ones demonstrated advantages in relation to chemicals. Moringa oleifera Lam is a natural polymer that has been gaining prominence in water treatment. It acts as a clarifying agent, providing a cationic protein that destabilizes the particles contained in a liquid medium. The main objective of the present work is to study the efficiency in terms of removing color and turbidity of raw water in order to obtain drinking water. For this purpose, different coagulant solutions were obtained utilizing three solutions of KCl in different concentrations (0.01, 0.1, and 1 M) and pure water combined with M. oleifera Lam seed. Each coagulant solution obtained was studied with concentrations ranging from 50 to 600 ppm of Moringa in solution. The pH was varied (4.0, 6.0, and 8.0) with 25% and 50% sodium hydroxide solution (NaOH) and hydrochloric acid (HCl), respectively. The tests were conducted with the “Jar Test Device” and the efficiency of the process was evaluated regarding the reduction of color and turbidity. The best results were found employing the coagulant solutions extracted with 1 M salt solution, pH 8.0, and different concentrations of coagulant solution. It is important to explain that the best results were in various concentration ranges, as the concentration of protein in solution becomes higher, the greater is its power as a coagulant. The lowest content of protein was found in the solution extracted with water, which consequently had the lowest values of color and turbidity removal.  相似文献   

10.
Abstract

This work was undertaken to determine the ability of an isotopic exchange kinetics method to measure the fixation of P by soils. The parameter, Pfix, the ratio of introduced carrier‐free 32P over 32P remaining in solution after one minute of exchange, was determined on a wide range (n = 127) of samples from surface horizons of temperate and tropical soils. Pfix was compared to two parameters derived from adsorption isotherms, the maximum quantity of adsorbed P (Pmax) and the quantity of P to be adsorbed to reach a concentration in solution of 0.2 mg P/L (Po.2). Results showed that Pfix was at least as good as Pmax and Po.2 to estimate the soil fixing capacity. Pfix was correlated to the clay and iron oxide (Fed) contents, and highly significant correlations with Fed were observed for Pfix than for Pmax or Po.2. The isotopic exchange kinetics method can be recommended to determine the soil phosphate fixing capacity. Moreover, because of its accuracy and the minimal disturbance of the soil‐solution equilibrium, the method could be used for routine analysis of soil P‐fertility status.  相似文献   

11.
12.
Abstract

The usefulness of the nitrate‐specific ion electrode (NE) for the determination of nitrate nitrogen (NO3‐N) in surface and ground water was determined. The NE method had several advantages that made it superior to the phenoldisulfonic acid (PDS) method in our environmental quality studies. Samples could be analyzed quickly and with a minimum of sample preparation. Sample coloration and soluble salts did not interfere with the performance of the electrode. Range of detection without dilution was much wider than by the PDS method. Also, the values obtained by the NE method, although slightly greater than those obtained by the PDS method, were satisfactory.  相似文献   

13.
A method is described for the rapid and simple assay of soil β-glucosidase activity. It involves colorimetric estimation of ρ-nitrophenol released by β-glucosidase activity when soil is incubated in McIlvaine buffer (pH 4.8) with ρnitrophenyl βd-glucoside and toluene at 30°C for 1 hr. The method has been applied to three different soils. The range of β-glucosidase activity in cultivated soils was from 10.1 to 15.2 mµ mole per min per gram of dried soil. Km value for ρ-nitrophenyl β-d-glucoside was 3.3 × 10-4 M. Optimum pH was 4.8.  相似文献   

14.
Soil greenhouse gas (GHG) emissions are complex, and their study requires considerable sampling of field spatial and temporal differences. Manual and simple automated gas‐collection techniques used at multiple sites during specific time intervals are labor intensive. The objective of this work was to construct a device that can independently collect GHG samples with the accuracy and precision of manually drawn samples. An automated collector of terrestrial systems (ACTS) is a 24‐h, 7‐d/week programmable sampler used in the field for real‐time gathering and containment of soil GHG emissions. The sampler opens and closes an exterior soil gas chamber, mixes gases in the chamber by turning fans on/off, and utilizes programmable circuits to purge the system and draw a sample from the chamber with a pneumatic‐driven syringe. Each sample was stored in an evacuated vial held in a 30‐vial capacity carousel. Vial content was analyzed for carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) at the U.S. Department of Agriculture (USDA)–Agricultural Research Services (ARS) Agroecosystem Management Research Unit (AMRU). A Tracor MT‐220 gas chromatograph (GC) configured with a thermal conductivity detector (TCD) was used for CO2 analysis, and an automated gas‐sampling system (AGSS) attached to a Varian 3700 GC configured with flame ionization detection (FID) and electron capture detection (ECD) was used for CH4 and N2O analysis. Field and laboratory mean values and coefficients of variation (standards and field concentrations of CO2, CH4, and N2O ranging from ambient to 71 kg ha?1 d?1 had coefficients of variation ranging from 1.2 to 4.2%) were similar between ACTS and manually drawn samples. Results showed strong correlation (R2 = 0.81 to 1.00) between sampling methods. The sampler design provides a realistic and inexpensive approach for collecting emission samples while reducing human error associated with adverse sampling conditions and fatigue. The ACTS has potential for use in monitoring and comparing management practices in terrestrial systems to determine their contribution to GHG emissions.  相似文献   

15.
Among the wheat prolamins, D-type glutenins display a highly repetitive sequence similar to ω-gliadins, but they contain a cysteine, that allows them to be included in the gluten macropolymers. An ω-gliadin-like D-type glutenin, an α-gliadin, and an ω5-gliadin-like D-type glutenin were obtained as recombinant proteins and compared using synchrotron radiation circular dichroism. This technique evidenced the strong thermostability of the ω5-gliadin-like protein. The IgE reactivity of recombinant proteins was evaluated using 45 sera from wheat-allergic patients. The sera from patients diagnosed with cutaneous hypersensitivity to hydrolyzed wheat proteins often reacted with the ω-gliadin-like D-type glutenin and α-gliadin, whereas the IgE reaction was less frequent after dietary sensitization. So, these two proteins could be useful to diagnose these diseases. The sera from patients with exercise-induced anaphylaxis recognized the ω5-gliadin-like protein as a positive control and, less frequently, the other proteins tested. Only some sera from patients with baker's asthma reacted with the proteins tested.  相似文献   

16.
OBJECTIVE: To evaluate compliance with the World Health Organization's International Code of Marketing of Breast-milk Substitutes in primary care, after the introduction of strict local infant feeding guidelines. DESIGN: An audit form was sent to all community-based health professionals with an infant feeding remit. Walking tours were conducted in a random sample of community care facilities. SETTING: Greater Glasgow Primary Care Division. SUBJECTS: (1) Primary-care staff with an infant feeding remit; (2) community health-care facilities. MAIN OUTCOME MEASURES: Contact with manufacturers of breast-milk substitutes (BMS) and BMS company personnel, free samples or incentives, and advertising of BMS. RESULTS: Contact with company personnel was minimal, usually unsolicited and was mainly to provide product information. Free samples of BMS or feeding equipment were rare but childcare or parenting literature was more prevalent. Staff voiced concerns about the lack of relevant information for bottle-feeding mothers and the need to support the mother's feeding choice. One-third of facilities were still displaying materials non-compliant with the Code, with the most common materials being weight conversion charts and posters. CONCLUSIONS: Contact between personnel from primary care and BMS companies was minimal and generally unsolicited. The presence of materials from BMS companies in health-care premises was more common. Due to the high level of bottle-feeding in Glasgow, primary-care staff stated a need for information about BMS.  相似文献   

17.
We investigated the influence of fire return interval length on the ectomycorrhizal (ECM) community of a Pinus pinaster dominated forest and on the potential for common ECM networks (CMNs) between understorey shrubs and P. pinaster. ECM root tips were sampled from five shrub species belonging to the genera Arbutus, Cistus and Halimium and from maritime pine in four areas of central Portugal characterized by differing fire return interval length. Fungal symbionts were identified using molecular techniques with direct sequencing of the nrDNA ITS region.Twenty nine ECM species and sixteen non-ECM root inhabitants were identified. Six years after wildfire disturbance ECM species richness did not differ significantly between unburnt and burnt areas. Nine ECM fungal species were common to pine and shrubs and both their frequency of occurrence and proportion were significantly higher in the unburnt area when compared with both areas subjected to fire.Our study revealed that while the potential for CMNs between understorey shrub species and pine seemed to be maintained in the long fire return interval area, recurrent fires significantly reduced the frequency of occurrence and the proportion of common symbiont species. High fire frequencies could therefore delay the process of re-colonization by pine seedlings limiting their dispersal in new settings.  相似文献   

18.
19.

Purpose

The vegetation of the Campinaranas occurs in humid areas with hydromorphic sandy soils at the Amazon region. Thus, the determination and in situ monitoring of moisture content in Campinarana soils, besides the detection of subsurface layers are key measures for studying these soil–vegetation systems. Also, the application of ground penetrating radar (GPR) in deep sandy sedimentary sequence of Amazonia is a promising tool to enhance the knowledge on depositional and soil formation features.

Materials and methods

We studied representative soils of the Campinaranas at the National Park of Viruá, state of Roraima (Brazilian Amazonia), through the use of geophysical methods (soil moisture sensors and GPR). The study was applied in four sandy soils. Besides chemical and physical analysis of soils, soil moisture sensors were installed for monitoring during an entire hydrological year (2010/2011), and performed the calibration of sensors , coupled with imaging of the soil along transects with GPR.

Results and discussion

As a result of calibration of the soil moisture sensors we obtained a general equation with an R 2 greater than 0.9. There is an influence of soil moisture content and soil temperature in the distribution of vegetation types in Campinaranas. The use of GPR identified some determinants characteristics in these soils for the differentiating the Campinaranas, represented by spodic and C horizons.

Conclusions

The spodic horizons in soils under Forest Campinarana provided potential errors in the determination of soil moisture, requiring calibration data for the precise use of this device. The investigation of the soil through the GPR showed interesting results, which allowed continuous visualization of the main soil horizons along transects in the phytophysiognomies of Campinaranas.  相似文献   

20.
Exploitation of wildlife for meat in the tropics (‘bushmeat’) is a critical threat for biodiversity, particularly in Africa. Here, we investigate the importance of protected areas (National Parks and other forest parks) as sources for the trade by exploring patterns in pricing and condition of bushmeat carcasses. We surveyed carcass prices in a large sample of trading points (87 markets surveyed, over a 35,000 km2 area) in Cameroon and Nigeria in the Cross–Sanaga region of West Africa. We assessed evidence for national parks as the source of animals traded as bushmeat. The study area included rural and urban centers (Calabar, Nigeria, and Douala, Cameroon) close to important protected areas: the Cross River National Park in Nigeria, and Korup National Park in Cameroon. Both parks host very high species diversity, including a range of endemics. Prices increased with distance from national park boundaries, particularly in Cameroon, where parks may be less depleted than in Nigeria. There was evidence that trading points closer to parks were more likely to function as wholesalers, with meat moving onto further trading points, rather than being sold to the end consumer. Carcasses were more often smoked (a treatment aimed at preservation) if they were not sold to their final consumers; smoking was also commoner at larger trading points. Prices were higher close to the road network, where opportunities for further trade were more available. We consider how wildlife harvests in and around protected areas may be managed to minimize depletion of animal populations, and if protected areas may, on the principle of marine no-take zones, be sustainable sources for regulated harvests.  相似文献   

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