Colluvisols under cultivation in Schleswig-Holstein. 2. Carbon distribution and soil organic matter composition     

Lothar Beyer  Rüdiger Fründ  Uwe Schleuß  Christine Wachendorf 《植物养料与土壤学杂志》1993,156(3):213-217

Soils under intensive cultivation have altered due to water erosion. This study was conducted to determine whether soil organic matter (SOM) composition of the colluvial source (Ap horizons) differs from the colluvial sink (M horizons). The SOM of a sandy Catena with erodic Cambisols and colluvic soils (Colluvisols) in Schleswig-Holstein, Northwest Germany, was investigated. A wet chemical analysis was combined with CPMAS ¹³C-NMR spectroscopy. In one case a significant correlation between the SOM composition of the Ap horizon of the erodic Cambisol and the M horizon of the Colluvisol was high (r² = 0.904^-), whereas the correlation for the other set was much weaker (r² = 0.640*). Two possible paths of pedogenesis are discussed. About 70% of the SOM of the colluvial source is decomposed during translocation or after deposition. A selective preservation or new formation of humins in the M material is probable. These humins contain, obviously, large amounts of polysaccharides, which were not detected by the wet chemical analysis. Further investigations of colluvic and erodic soils are necessary in order to specify the SOM quality and its possible modification due to soil translocation and accumulation.  相似文献   

Structural identification of nonvolatile dimerization products of glucosamine by gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and nuclear magnetic resonance analysis     

Jun M  Shao Y  Ho CT  Koetter U  Lech S 《Journal of agricultural and food chemistry》2003,51(21):6340-6346

The degradation profile of glucosamine bulk form stressed at 100 degrees C for 2 h in an aqueous solution was studied. Column chromatography of acetylated product mixture led to isolation of two pure compounds (1b and 2b) and a mixture of at least three isomers (3b). 1a and 2a were identified as 5-(hydroxymethyl)-2-furaldehyde (5-HMF) and 2-(tetrahydroxybutyl)-5-(3',4'-dihydroxy-1'-trans-butenyl)pyrazine, respectively, by utilizing a variety of analytical techniques, such as GC-MS, LC-MS, on-line UV spectrum, (1)H and (13)C NMR, and DEPT, as well as (1)H-(1)H COSY. 3a was identified as 2-(tetrahydroxybutyl)-5-(2',3',4'-trihydroxybutyl)pyrazine, commonly known as deoxyfructosazine. In addition, glucosamine solid dosage form was exposed to 40 degrees C/75% relative humility for 10 weeks. Methanol extract of glucosamine solid dosage form was analyzed after acetylation by LC-MS, resulting in degradants 3b and 4b. 3a and 4a were, therefore, determined as deoxyfructosazine and 2,5-bis(tetrahydroxybutyl)pyrazine (fructosazine), respectively. Furthermore, the mechanisms of formation of identified degradation products are proposed and briefly discussed.  相似文献   

Model Experiments on the Influence of Artificial Humic Compounds on Chemodenitrification     

Kappelmeyer  Uwe  Kuschk  Peter  Stottmeister  Ulrich 《Water, air, and soil pollution》2003,147(1-4):317-330

Chemodenitrification is of importance in both soils and the treatment of some types of wastewater. During model experiments,the impact of various conditions, such as pH and especially artificial humic matter and oxygen on this process was studied to build upkinetic models. The chemodenitrification rate decreased due to the ongoingautoxidation/polymerization of hydroquinone to artificial humic matterfrom 11.02 μg (L h)^-1 after 7 days autoxidation to 5.38 μg (L h)^-1 after 14 days at pH 4 under aerobic conditionsand an initial nitrite concentration of 250 μg L^-1. At the same pH,with the same nitrite concentration, and in the presence of Roth humic matter(2 mg L^-1) under aerobic conditions, the chemodenitrification rate was0.73 μg (L h)^-1, whereas under anaerobic conditions itwas considerably higher (2.88 μg (L h)^-1). In anothermodel experiment, it was shown that the amount of nitrite incorporated into the artificial humic matter was less then 1%. Further, it was found that the main reaction product of chemodenitrification is NO.  相似文献   

Colluvisols under cultivation in Schleswig-Holstein. 1. Genesis,definition and geo-ecological significance     

Lothar Beyer  Carsten Köbbemann  Jens Finnern  Dirk Elsner  Uwe Schleuß 《植物养料与土壤学杂志》1993,156(3):197-202

In Schleswig-Holstein, F.R.G., two typical soil associations from loamy boulder marl and loamy pleistocene sands were mapped and ecologically characterized in order to show the necessity of an adequate classification of Colluvic Cumulic Anthrosols (Colluvisols). More than 50% of the original soils have been altered by erosion. The depth of the colluvic wM horizon ranges between 10 cm and more than 100 cm. The amounts of soil organic matter and plant available nutrients are much higher in the Colluvisols than in the haplic soils. Soil classification does not deal with all these aspects with regard to mapping of colluvic soils. In the German soil classification adequate and ecologically significant definitions and instructions of the nomenclature of colluvic soils are not available. Therefore, a proposal is presented to classify colluvic soils. In addition the threshold value of 0.6% soil organic matter in sandy parent material is too low in order to distinguish a Bv from a M horizon; 1.0% would be a more acceptable value. It would be necessary to investigate yield on erodic, non-erodic and colluvic soils in order to determine the effect of erosion and accumulation on crop yield.  相似文献   

Comprehensive authentication of (E)-alpha(beta)-ionone from raspberries, using constant flow MDGC-C/P-IRMS and enantio-MDGC-MS     

Sewenig S  Bullinger D  Hener U  Mosandl A 《Journal of agricultural and food chemistry》2005,53(4):838-844

A new coupling system of GC-GC, connected via a Multi Column Switching Device MCS2 for measuring isotope ratios, is introduced. By means of several standard substances the precise and accurate measurement of isotopic values is proved. First applications concerning the authentication of raspberry aroma compounds are established. Consequently, the combination of constant flow multidimensional gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry (MDGC-C/P-IRMS) is applied to the authenticity assessment of (E)-alpha(beta)-ionone from six different raspberry cultivars. Furthermore, 12 commercially available raspberry products and samples of (E)-alpha(beta)-ionone, some declared to be natural, are investigated. delta(2)Eta(V)(-)(SMOW) and delta(13)C(V)(-)(PDB) values of (E)-alpha(beta)-ionone are determined, and characteristic authenticity ranges were concluded from raspberries by correlation of both delta(2)Eta(V)(-)(SMOW) and delta(13)C( V)(-)(PDB) values. The results are correlated with the determination of enantiomeric purities of (E)-alpha-ionone, using stir bar sorptive extraction enantio-multidimensional gas chromatography mass spectrometry (SBSE-enantio-MDGC-MS).  相似文献   

Screening of mango (Mangifera indica L.) cultivars for their contents of flavonol O- and xanthone C-glycosides, anthocyanins, and pectin     

Berardini N  Fezer R  Conrad J  Beifuss U  Carle R  Schieber A 《Journal of agricultural and food chemistry》2005,53(5):1563-1570

With respect to their browning potential and in consideration of a combined recovery of pectin and phenolic compounds, peels of 14 cultivars and the flesh of nine cultivars of mango (Mangifera indica L.) fruits were analyzed for their contents of flavonol O- and xanthone C-glycosides by high-performance liquid chromatography (HPLC)-diode array detection-electrospray ionization mass spectrometry (ESI-MS). While total amounts of up to 4860 mg/kg dry matter demonstrated the peels to be a rich source of phenolic compounds, only traces could be detected in the flesh. The profile of flavonol glycosides of the peels proved to be highly characteristic and may therefore serve as a tool for authenticity control of mango puree concentrate, which is often produced from unpeeled fruits and represents an important intermediate for the production of mango nectars. Two compounds were isolated by preparative HPLC, and their structures were elucidated on the basis of ESI-MS as well as NMR spectroscopy, establishing the two compounds as rhamnetin 3-O-beta-galactopyranoside and rhamnetin 3-O-beta-glucopyranoside, respectively. In the peels of red-colored cultivars, cyanidin 3-O-galactoside and an anthocyanidin hexoside so far not reported in mango could tentatively be identified. The contents and degrees of esterification of pectins extracted from the lyophilized peels ranged from 12.2 to 21.2% and from 56.3 to 65.6%, respectively, suggesting mango peels also as a promising source of high-quality pectin.  相似文献   

Detection of phloridzin in strawberries (Fragaria x ananassa Duch.) by HPLC-PDA-MS/MS and NMR spectroscopy     

Hilt P  Schieber A  Yildirim C  Arnold G  Klaiber I  Conrad J  Beifuss U  Carle R 《Journal of agricultural and food chemistry》2003,51(10):2896-2899

The phenolic profile of strawberry fruits (Fragaria x ananassa Duch., Rosaceae) was investigated by high-performance liquid chromatography with photodiode array detection. A peak displaying retention time and UV spectral data identical to those of phloridzin (phloretin 2'-O-beta-d-glucoside), a dihydrochalcone glucoside so far considered characteristic of apples, was monitored. For further characterization, crude extracts of strawberries were purified on polyamide, and the target compound was isolated by preparative and analytical HPLC. Structure elucidation was performed on the basis of APCI- and ESI-MS in the negative ion mode as well as by 1D and 2D NMR spectroscopy using authentic phloridzin for comparison. The d-configuration of the sugar moiety was established by HPLC analysis of the corresponding acyclic 1-deoxy-1-(N-acetyl-alpha-methylbenzylamino)alditol acetate. Apart from its chemotaxonomic relevance, this first report on the occurrence of phloridzin in strawberries is of particular interest for the authenticity control of strawberry products such as juices, jams, and fruit preparations since phloridzin has so far been used for the detection of fraudulent admixtures.  相似文献   

Large‐scale identification of hot spots for soil carbon demand under climate change and bioenergy production          下载免费PDF全文

Uwe Franko  Felix Witing  Greta Jäckel  Martin Volk 《植物养料与土壤学杂志》2015,178(2):199-208

Global change scenarios predict an increased risk for declining amounts of soil organic matter (SOM) for Central Germany. Within this region the production of bioenergy is one important strategy to counteract the rising anthropogenic CO₂‐emissions. Both issues have a close connection: SOM is an important basis for soil productivity and requires a steady reproduction flux. Bioenergy production requires productive soils and partly consumes plant biomass C. Therefore, the available amount for SOM reproduction is reduced. This study provides a methodology for the large‐scale identification of areas with possible conflicts between bioenergy production and SOM reproduction based on (1) the prediction of climate change impact on SOM reproduction and (2) an analysis of the regional distribution of biogas plants. With the C demand index (CDI) and the capacity index (CAP), two indicators were developed which enable the identification of hot spots of high carbon demand for SOM reproduction due to climate change and the usage of bioenergy. As a result of low data requirements, the indicators are widely applicable and transferable to other large‐scale studies. The proposed methodology was applied to Central Germany as a pilot region. Results indicate a growing demand (10–40%) of fresh organic C from biomass for SOM production in comparison to the current level. The analysis reveals that the bioenergy C demand is not evenly distributed within the study region. It also shows some regional clustering. Furthermore, the analysis identifies certain hot spots of a high C demand, where a high capacity of biogas production may conflict with rising demands for biomass to mitigate climate change effects on SOM storage. The hot spot areas—identified and selected on a large scale—can subsequently be analyzed in more detail on a local to farm scale by using high‐resolution data and models which enable the quantification of soil C dynamics.  相似文献   

Anaplasmosis in cattle in Switzerland   总被引：1，自引：0，他引：1  

U Braun  G Winkler  P Wild  R Eicher 《Schweizer Archiv für Tierheilkunde》1987,129(3):113-124

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Sources of uncertainty in pharmacokinetic prediction     

W H Braun  J M Waechter 《Journal of animal science》1983,56(1):235-243

Assessment of the hazard associated with residues in food animals must be based on an accurate estimate of the residue levels present in the final food product, as well as animal toxicology studies to determine the potential untoward effects of these residues. Extrapolation of residue levels or toxic effects produced by the administration of a chemical in one species to predict residue levels or toxicology that may be produced by lower doses in the same species or by equivalent or lower doses in another species is associated inextricably with knowledge of the pharmacokinetics of the chemical. There are several factors that may influence the pharmacokinetics of xenobiotics which, if left unconsidered, may introduce uncertainty in the predictions of toxicity following any chemical exposure. Two of these factors are dose level and species differences. Because initial toxicity studies are designed to characterize the type of toxicity and to elucidate target organ effects the use of high doses is the accepted practice. However, because biotransformation and excretion of many chemicals are capacity-limited processes, extrapolation of toxicity to lower doses, without adequate pharmacokinetic information at those lower dose levels may result in overestimation of predicted toxicity. Furthermore, determination of tissue residue levels following administration of doses that saturate these processes may result in an overestimation of residues remaining following lower doses. Finally extrapolation of toxicity results across species may result in an over or underestimation of hazard without adequate information on the pharmacokinetics of the chemical in both species.  相似文献