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941.
Fungal decomposition of and phosphorus transformation from spruce litter needles (Picea abies) were simulated in systems containing litter needles inoculated with individual saprotrophic fungal strains and their mixtures. Fungal strains of Setulipes androsaceus (L.) Antonín, Chalara longipes (Preus) Cooke, Ceuthospora pinastri (Fr.) Höhn., Mollisia minutella (Sacc.) Rehm, Scleroconidioma sphagnicola Tsuneda, Currah & Thormann and an unknown strain NK11 were used as representatives of autochthonous mycoflora. Systems were incubated for 5.5 months in laboratory conditions. Fungal colonization in systems and competition among strains were assessed using the reisolation of fungi from individual needles. After incubation, needles were extracted with NaOH and extracts were analysed using 31P nuclear magnetic resonance spectroscopy (NMR). Needle decomposition was determined based on the decrease in C:N ratio. Systems inoculated with the basidiomycete S. androsaceus revealed substantial decrease in C:N ratio (from 25.8 to 11.3) while the effect of ascomycetes on the C:N ratio was negligible. We suppose that tested strains of saprotrophic ascomycetes did not participate substantially in litter decomposition, but were directly involved in phosphorus transformation and together with S. androsaceus could transform orthophosphate monoesters and diesters from spruce litter needles into diphosphates, polyphosphates and phosphonates. These transformations seem to be typical for saprotrophic fungi involved in litter needle decomposition, although the proportion of individual phosphorus forms differed among studied fungal strains. Phosphonate presence in needles after fungal inoculation is of special interest because no previous investigation recorded phosphonate synthesis and accumulation by fungi. Our results confirmed that the 31P NMR spectroscopy is an excellent instrumental method for studying transformations of soil organic phosphorus during plant litter decomposition. We suggest that polyphosphate production by S. androsaceus may contribute to the phosphorus cycle in forest ecosystems because this fungus is a frequent litter colonizer that substantially participates in decomposition. 相似文献
942.
Ichikawa Yoichi Hayami Hiroshi Sugiyama Taishi Amann Markus Schöpp Wolfgang 《Water, air, and soil pollution》2001,130(1-4):301-306
In order to contribute to the analysis and solution of regional scale environmental problems in East Asia, we developed a tool for the comprehensive assessment of alternative policy options to improve air quality. This tool projects the future regional energy supply, calculates the emission levels of sulfur dioxide and estimates the geographical pattern of sulfur deposition resulting from emissions. Sulfur deposition in Japan through 2030 was forecasted for various energy supply and emission control scenarios using the analysis tool. Future sulfur depositions were calculated from the source-receptor matrix for 1995 and the growth rate of emission for the source subregion. In the case of the current legislation scenario, anthropogenic SO2 emissions in East Asia would grow by 34 percent and sulfur deposition in Japan would increase by approximately 20 percent between 1995 and 2030. This increase in sulfur deposition over these 35 years is sligthly less than the contribution from volcanic emission to sulfur deposition in Japan. In the case of the hypothetical dirty scenario for China, sulfur deposition in several grids which face the Sea of Japan would double by 2030. 相似文献
943.
Klimont Z. Cofala J. Schöpp W. Amann M. Streets D.G. Ichikawa Y. Fujita S. 《Water, air, and soil pollution》2001,130(1-4):193-198
Starting from an inventory of SO2, NOx, VOC and NH3 emissions for the years 1990 and 1995 in East Asia (Japan, South and North Korea, China, Mongolia and Taiwan), the temporal development of the emissions of the four air pollutants is projected to the year 2030 based on scenarios of economic development. The projections are prepared at a regional level (prefectures or provinces of individual countries) and distinguish more than 100 source categories for each region. The emission estimates are presented with a spatial resolution of 1×1 degree longitude/latitude. First results suggest that, due to the emission control legislation taken in the region, SO2 emissions would only grow by about 46 percent until 2030. Emissions of NOx and VOC may increase by 95 and 65 percent, respectively, mainly driven by the expected increase in road traffic volume. Ammonia, mainly emitted from agriculture, is projected to double by 2030. 相似文献
944.
Stipanovic AJ Hennessy PJ Webster FX Takahashi Y 《Journal of agricultural and food chemistry》2004,52(8):2301-2308
The potential utility of micrometer-sized particles as controlled-release devices for the volatilization of insect pheromones for mating disruption applications is evaluated in this study for two pheromone/model compound systems (codlemone/1-dodecanol and disparlure/1,2-epoxyoctadecane). To expedite the measurement of release rates from these particle devices, two techniques based on thermogravimetric analysis (TGA) have been exploited: isothermal TGA (I-TGA) at elevated temperatures (40-80 degrees C) with N(2) convection and volatilization temperature (VT) by dynamic TGA. A correlation between these two methods has been established. Samples that exhibit a higher VT provide a lower release rate from a particle substrate. Using these techniques, it has been demonstrated that chemical interactions between adsorbed liquids and particle surfaces may play a small role in defining release characteristics under conditions of low surface area, whereas parameters associated with total surface area and micropore structure appear to be much more significant in retarding evaporation for uncoated particles containing an adsorbed liquid. Additional regulation of release rates was achieved by coating the particle systems with water-soluble or water-dispersible polymers. By careful selection of particle porosity and coating composition, it is envisioned that the evaporation rate of pheromones can be tailored to specific insect control applications. 相似文献
945.
José?CrossaEmail author Rong-Cai?Yang Paul?L.?Cornelius 《Journal of Agricultural, Biological & Environmental Statistics》2004,9(3):362-380
In agriculture and plant breeding the most important genotype × environment interaction pattern is crossover genotype × environment
interaction. Procedures using linearbilinear models are used to find disjoint subsets of sites or genotypes with negligible
crossover genotype × environment interaction. In terms of correlations, these subsets of sites or genotypes should be such
that pairs of sites have nearly perfect positive genetic correlations. Perfect positive genetic correlation between sites
is a sufficient, but not a necessary, condition for a non-COI pattern. The main objective of this study was to use the mixed
model theory to confirm that the subsets of sites and genotypes formed by using the linear-bilinear models have negligible
crossover genotype × environment interaction. If there is no significant crossover interaction in a subset of sites or genotypes,
then the mixed model should be able to confirm this by nonrejection of the hypothesis that the covariance structure has perfect
genetic correlation. Mixed model analysis of results from two multisite cultivar trials confirmed the validity of the procedures
using linear-bilinear model methods for clustering sites and genotypes into noncrossover genotype × environment interaction
subsets. 相似文献
946.
Topsoils affected by surface mining suffer severe physical degradation and lose most of their earthworm populations. After mining, replaced soils are planted to grassland and managed to improve soil structure. Earthworm inoculation into selected restored areas produced populations similar to those of undisturbed soils within 3 years. Soil properties in inoculated areas were compared with those of controls to evaluate the contribution of casts to bulk soil aggregation, and soil organic matter and root content responses to earthworm activity. Crumb porosity and coarse particle content were measured in water-stable macro-aggregates and earthworm casts to establish whether aggregates were formed by earthworms. Over a 5- to 6-year period, inoculation increased stable aggregation (>2 μm, >60 μm and >3 mm), even at 0- to 5-cm depth where it reduced soil organic matter content. Productivity and root content were also increased by inoculation; roots and organic matter were re-distributed to greater depth. Crumb porosity decreased with casts > aggregates (inoculated plots) > aggregates (control plots). Coarse particle content increased with casts < aggregates (inoculated plots) < aggregates (control plots). Coarse particle and porosity data were consistent with much of the newly aggregated soil being processed and formed by earthworms as casts. Whilst levels of soil organic matter were often closely associated with percentage stable aggregation, root content showed weaker associations. Aggregation percentage was most closely associated with abundance of Aporrectodea longa , although at particular depths significant correlations were also obtained for Aporrectodea caliginosa and Lumbricus terrestris . Results suggest that earthworms, rather than plant roots, initiate aggregation in severely degraded grassland soils. 相似文献
947.
Cécile?VillenaveEmail author Khadi?Leye Jean-Luc?Chotte Robin?Duponnois 《Biology and Fertility of Soils》2003,38(3):161-169
Ten leguminous trees, four exotic species (Australian Acacia) and six indigenous species (three Sahelian Acacia spp. and three Sesbania spp.), were grown for 4 months in a natural Sahelian soil inoculated with or without the endomycorrhizal fungus, Glomus intraradices. In control trials, the determinant factor structuring the soil nematode fauna was the plant species, related plants having a similar influence on the nematode community in the soil. Soil nematode abundance increased from exotic acacias (3.3 g-1 dry soil) to native acacias (11.5 g-1 dry soil) and Sesbania species (17.6 g-1 dry soil). Plant feeding nematodes (mainly Scutellonema and Tylenchorhynchus) were significantly less abundant under exotic acacias (1.4 g-1 dry soil) than under native acacias (7.2 g-1 dry soil) or Sesbania species (7.3 g-1 dry soil). Bacterial feeding nematode density increased from exotic acacias (1.2 g-1 dry soil) to native acacias (3.0 g-1 dry soil) and Sesbania species (7.7 g-1 dry soil) as total densities. However, the differences in the structure of the nematode communities between plant groups were suppressed in the presence of the mycorrhizal fungus. In fact, no difference in nematode densities remained between plant groups when G. intraradices developed in several dominant taxa belonging to different trophic groups, particularly: Tylenchorhynchus, Apelenchina, Cephalobus and Dorylaimoidea. This study clearly indicated that inoculation with the arbuscular mycorrhizal fungus G. intraradices diminished the plant-specific effect on the structure of the soil nematode community. 相似文献
948.
Brent?A.?CoullEmail author Maura?Mezzetti Louise?M.?Ryan 《Journal of Agricultural, Biological & Environmental Statistics》2003,8(3):253-270
This article uses a Bayesian hierarchical model to quantify the adverse health effects associated with in-utero exposure to
methylmercury. By allowing for study-to-studyas well as outcome-to-outcome variability, the approach provides a useful meta-analytic
tool for multi-outcome, multi-study environmental risk assessments. The analysis presented here expands on the findings of
a National Academy of Sciences (NAS) committee, charged with advising the United States Environmental Protection Agency (EPA)
on an appropriate approach to conducting a risk assessment for methylmercury. The NAS committee, for which the senior author
(Ryan) was a committee member, reviewed the findings from several conflicting studies and reported the results from a Bayesian
hierarchical model that synthesized information across several studies and for several outcomes. Although the NAS committee
did not suggest that the hierarchical model be used as the actual basis for a methylmercury risk assessment, the results from
the model were used to justify and support the final recommendation that the risk analysis be based on data from a study conducted
in the Faroe Islands, which had found a positive association between in-utero exposure to methylmercury and impaired neurological
development. We considera variety of statistical issues, but particularly sensitivity to model specification. 相似文献
949.
Using segmented regression models to fit soil nutrient and soybean grain yield changes due to liming
Xiufu?ShuaiEmail author Zhijun?Zhou Russell?S.?Yost 《Journal of Agricultural, Biological & Environmental Statistics》2003,8(2):240-252
Frequently soil-plant relationships and responses are complex combinations of increases-level-decreases consisting of linear
segments of differing slope. Segmented regression is very useful to express and quantify such relationships and responses.
Fitting segmented regression models to such data, however, remains a challenge. The problem is in estimating the join points
and coefficients. We use median functions to express segmented regression models, and estimate the join points by standard
estimation routines such as Marquardt, Newton, and doesn’t use derivatives (DUD) methods that are available in statistical
software such as SAS. Segmented straight-line models are fit to data reflecting soil Manganese (Mn), Calcium (Ca), Phosphorus
(P), and soybean yield changes under different soil pH conditions due to liming. A systematic comparison of the slopes and
join points suggests that different mechanisms are limiting soybean yield at different intervals as soil pH increased. 相似文献
950.
Gas chromatographic determination of clopidol in chicken tissues 总被引:1,自引:0,他引:1
L G Ekstr?m J Kuivinen 《Journal of the Association of Official Analytical Chemists》1984,67(5):955-957
A method has been developed for the determination of clopidol residues in chicken tissues. After extraction and cleanup, clopidol is esterified in a 2-phase system to clopidol propionate, which is determined by gas chromatography. The 2-phase system includes, in addition to the clopidol dissolved in methanol, aqueous borax solution, hexane, propionic anhydride, and pyridine. Use of these reagents precludes the use of explosive or carcinogenic chemicals in the derivatization step, and the method is therefore suitable for routine laboratory analysis. Levels of 0.5 ppb clopidol in tissue can be determined. 相似文献