Analysis of fiber content in flax stems by near-infrared spectroscopy     

Barton FE  Akin DE  Morrison WH  Ulrich A  Archibald DD 《Journal of agricultural and food chemistry》2002,50(26):7576-7580

The conventional means of measuring the fiber content of flax is time-consuming and laborious, and the results obtained vary with the analysis technique used. The plant tissues must first be "retted", a process by which the fibers are separated from the rest of the stem, either by indigenous organisms in the soil when the stems are left in the field or by water (anerobic bacteria) or enzymatic retting. The fiber content is then determined by mechanical or manual separation. In this study, fiber content of flax stems was measured rapidly and objectively by near-infrared spectroscopy (NIRS) using whole pieces of stem in a large cell, in reflectance mode. Compared to the conventional method, the standard error of performance of the NIRS method was between 0.96 and 1.45% (dry matter basis), depending on the model and data processing used. NIRS calibrations were generated by hand separation of fiber from water-retted specimens. The water retting procedure takes several days to complete and requires considerable trained labor to complete the hand separation step. The NIRS procedure was conducted on pieces of stem to simulate measurement in the field.  相似文献   

Soil-living parasitic Hymenoptera: comparison between a forest and an open landscape habitat     

Werner Ulrich 《Pedobiologia》2004,48(1):59-69

Community structures and local diversity patterns of parasitic Hymenoptera with soil and leaf litter hosts were studied in a German beech forest and a meadow. Hymenoptera appeared to be one of the most species-rich taxa associated with the soil. Eighty-eight species were found in the meadow (total density of 128 ind. m⁻² yr⁻¹) and 188 species (149 ind. m⁻² yr⁻¹) in the forest. The mean parasitism rates were above 60% for parasitoids of mycetophagous Diptera and between 7% and 26% for parasitoids of saprophagous Diptera. Species overlap between both habitats was higher than expected from a random sample model. Species common to both habitats were primarily parasitoids of predatory Coleoptera. High mean densities of these species support the hypothesis of a positive correlation between local abundance and range size.  相似文献   

Die Beeinflussung der Bodenlösung durch Saugkerzen aus Ni-Sintermetall und Keramik     

W. Hetsch  F. Beese  B. Ulrich 《植物养料与土壤学杂志》1979,142(1):29-38

Influencing soil solution by suction cup material (Ni, ceramics) The influence of suction cup material (ceramics, Ni) on the chemical composition of the soil solution was tested in the laboratory by percolating soil solutions of different concentration (pH ～ 4.0). Ceramic cups of P 80 material can be used for the collection of soil solution and its determination for the concentrations of H, Na, K, NH₄, Ca, Mg, Mn, Al, S, Cl and NO₃. They can't be used to determine P-concentrations. The cups must be prepared and preconditioned by leaching large amounts of equilibrium soil solution which should not be oversaturated with respect to the solubility product of AlOHSO₄. The changes in the concentration of extracted soil solution when it passes through the cups depend upon the extracted volume. The lower the volume, the greater are the changes. Sintered Ni-cups show many severe disadvantages (decreasing permeability, insufficient resistence against acid solutions, large variability among single cups), and can only be used for cases where Na, Ca, K, and S are to be determined. Ceramic cups of the type ‘Czeratzki’ are comparable with those of P 80. However, they can only be used, when the concentrations don't vary too much and large amounts of water can be extracted.  相似文献   

VDI-Bericht 500: Saure Niederschläge–Ursachen und Wirkungen. 432 Seiten, 244 Abb., 120 Tab.; VDI-Verlag GmbH,Postfach 1139, 4000 Düsseldorf 1; 236,– DM     

B. Ulrich 《植物养料与土壤学杂志》1984,147(5):645-645

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Aspects of phytoremediation of organic pollutants   总被引：1，自引：0，他引：1  

Stefan Trapp  Ulrich Karlson 《Journal of Soils and Sediments》2001,1(1):37-43

Phytoremediation is a quite novel technique to clean polluted soils using plants. In theory, phytoremediation methods are cheap, are accepted by the public and, compared to physical or chemical approaches, are ecologically advantageous. Until today, however, there are only a few examples of successful applications. One reason is that the processes involved are complex, and a full clean up may require many years. Plants affect the water balance of a site, they change redox potential and pH, and stimulate microbial activity of the soil. These indirect influences may accelerate degradation in the root zone or reduce leaching of compounds to groundwater. Compounds taken up into plants may be metabolised, accumulated, or volatilised into air. Based on these processes, several phytoremediation methods have been developed: Phytoextraction, rhizofiltra-tion, phytostabilisation, rhizo and phytodegradation, pump and tree, land farming, phytovolatilisation, hydraulic control and more. Already in use are plants (and here willow, poplar and grass) for the degradation of petroleum products, aromatic hydrocarbons (BTEX), chlorinated solvents, explosives and cyanides. However, phytotoxicity and pollutant mass balances were rarely documented. Often, the success of the projects was not controlled, and only estimates can be made about the applicability and the potential of phytoremediation. This lack of experience about possibilities and limitations seems to be a hindrance for a broader use of these techniques.  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   

Heinrich Walter: Bekenntnisse eines Ökologen. Gustav Fischer Verlag Stuttgart, 2. Auflage, 345 S. mit 12 Abb. und 7 Kartenskizzen, 1982     

B. Ulrich 《植物养料与土壤学杂志》1982,145(4):421-421

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The Transfer of Chemical Elements within a Heath-Ecosystem (Calluna vulgaris) in Northwest Germany     

E. Matzner  B. Ulrich 《植物养料与土壤学杂志》1980,143(6):666-678

The purpose of this investigation was to describe the element budget of a heathland area in Northwest Germany by measuring the fluxes of elements within the ecosystem. The following fluxes were considered: input by precipitation, canopy-drip, mineralisation, ion uptake, litterfall, output with seepage water. The elements H, Na, K, Ca, Mg, Mn, Fe, Al, S, P, CI, NO, NH, N_org were analysed, the period of investigation was one year. The results demonstrate the high importance of deposited nutrients like N (especially No3), Ca and Mg for the element budget and the stability of a heath-ecosystem. The internal turnover of K, Ca, Mg and Mn within the ecosystem mainly took place by leaching. No leaching was found for N, P, AI, Fe, S, CI, Na. For these elements litterfall was the dominant internal way of cycling. The humus layer was a sink for total-N, NO, Ca, Mg, Mn, Fe and S. NO, Ca, Mg, Mn and S were removed from the percolating solution, while for Fe and especially N and Mn an inhibition of mineralisation was found. The element balance for the mineral soil showed that this part is a sink for Hand a source mainly for Al, Ca and Mg, less for K and Na. From the cation/anion balance of the storage changes in mineral soil the ecosystem-internal H ion production was calculated as 0.4 keq per ha and year. It may be traced back to an uptake of NH, and dissociation of fulvic acids in the mineral soil. The results are discussed with respect to the development, stability and management of heath-ecosystems.  相似文献   

Phosphate Fractionation in Soils and the Isotopically Exchangeable Phosphate of Various Phosphate Fractions     

P. K. Khanna  B. Ulrich 《植物养料与土壤学杂志》1967,117(1):64-65

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Natural and anthropogenic components of soil acidification   总被引：2，自引：0，他引：2  

Bernhard Ulrich 《植物养料与土壤学杂志》1986,149(6):702-717

The following 8 theses are theoretically founded and experimentally quantified. 1. Rocks contain only bases and no acid precursors. Therefore, with the exception of sulfide containing rocks, soils cannot acidify as a result of atmospheric rock weathering. 2. A consumption of protons in rocks and soils results in a decrease of their acid neutralizing capacity (ANC) and can result in the buildup of a base neutralizing capacity (BNC). Strong soil acidification leads to the formation of stronger acids from weaker acids in the solid phase; this may be connected with a decrease in the BNC. 3. Weak acids (carbonic acid) lead in geological times to the depletion of bases without a larger accumulation of labile cation acids. Strong acids (HNO₃, organic acids, H₂SO₄) can lead within a few decades to soil acidification, i.e. to leaching of nutrient cations and the accumulation of labile cation acids. 4. The acid input caused by the natural emission of SO₂ and NO_x can be buffered by silicate weathering even in soils low in silicates. 5. The cause of soil impoverishment and soil acidification is a decoupling of the ion cycle in the ecosystem. 6. Acid deposition in forest ecosystems which persists over decades leads to soil acidification. 7. Formation and deposition of strong acids with conservative anions (SO₄, NO₃) shifts soil chemistry into the Al or Al/Fe buffer range up to great soil depth. In such soils eluvial conditions prevail throughout the solum and even in upper part of the C horizon: in connection with the decomposition of clay minerals, Al and eventually Fe are being eluviated. The present soil classification does not include this soil forming process. 8. In the long run, soil acidification by acid deposition results in the retraction of the root system of acid tolerant tree species from the mineral soil, and in water acidification.  相似文献