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1.
Pelvis size plays an important role to prevent dystocia in cattle caused by the foeto-maternal disproportion in commonly primiparous females. The reproducibility and repeatability are two important aspects for the reliability of the measurements to use in the selection of cattle for culling. Pelvic measures were taken with a Rice pelvimeter from 224 young cattle (180 females and 44 males) of four beef breeds in South Africa. One experienced and two inexperienced observers each measured pelvic height and width twice. The proportion measurements with a maximum difference of 0.5 cm within animal compared with the first measurement by the experienced observer are around 80% and by the inexperienced observers around 50% for pelvic height and around 60% for pelvic width. Breed and sex do not affect the reliability of pelvimetry by an experienced observer. Under- and overestimation of pelvis size were observed in inexperienced observers, which seems to be unrelated to breed and sex.  相似文献   
2.
With the electro–ultrafiltration (EUF) technique, the plant availability of several plant nutrients in soils can be characterized. The basic principle of EUF is that an electric field is induced using platinum electrodes. Ions in the soil suspension move either to the cathode or to the anode and are filtrated through ultra‐membrane filters. In the standard EUF procedure, two extractions steps are used: 30 min at 20°C and 5 min at 80°C. However, the determination of micronutrients and heavy metals with the standard EUF procedure is not possible, because the solubility of these elements in water is low and most of the watersoluble elements are precipitated when passing the platinum electrodes. The addition of DTPA, a well known complexing agent, during a third EUF fraction (5 min at 80°C) enables extraction of micronutrients and heavy metals. Highest concentrations in the 33 soils of the study were found for iron, followed by zinc, manganese, lead, copper, and nickel. Lower concentrations were obtained for cobalt, chromium, cadmium, and molybdenum. For two soils, the EUF/DTPA procedure was compared to CaCl2/DTPA and EDTA soil extraction methods, showing that higher or comparable amounts were found with CaCl2/DTPA and much higher amounts with the EDTA method. These results reveal that the EUF/DTPA technique in principle can be used for the determination of plant‐available micronutrients and heavy metals. However, in a next step the relationship between EUF/DTPA‐extractable elements and their availability for plants needs to be quantified.  相似文献   
3.
Silviculture, forest conversion and technical tools of ecosystem management, such as forest liming, display their effects at the landscape level. Therefore their planning and control should take place at the same scale. The primary objective of this work was to assess soil chemical properties and their changes in relationship to ecosystem management, especially forest conversion and forest liming. We calculated scenario models, based on regression analysis, which allow such an examination in the context of understanding landscape processes which can be expected to operate in the sampling region. Stepwise multiple linear regression analysis was used to predict soil chemical attributes (base saturation, pH, C/N content and stock, exchangeable stocks of Ca and Mg) as indicators of site stability or off-site effects of forest ecosystems such as effects on clean drinking water from forested watersheds. Because of space limitations, in this paper only the modelling results of base saturation are presented. Base saturation was used as an integrative example for other soil chemical properties. The transformation of measurements to the regional scale, i.e., the regionalization, was calculated for the forested parts of two test regions in the Black Forest on the basis of measured chemical properties of 90–150 soil profiles per test region. The models have a spatial resolution of 50×50 m, which is a spatial scale relevant for forestry practice and forest management. Topographic variables (e.g., elevation, aspect, slope gradient, and slope length), the stratigraphic classification of the geologic substrate, stand characteristics from forest inventory data, and finally technical information about forest liming were the auxiliary variables (secondary site properties) that provided indirect information about base saturation and were available for the whole forested area of the test regions. Base saturation could be predicted with an accuracy of ~50–70% (in terms of the multiple R2) by using these properties as predictor variables in multiple linear regression analyses. The explained proportion of variance was unexpectedly high considering the high geomorphological heterogeneity of the two test regions. Based upon the regionalization models, it was possible to establish scenarios showing the landscape-related effects on base saturation that may be achieved by forest conversion towards a higher proportion of forests with broad-leaved mixed stands and by forest liming. These scenarios allow the interactions between several influencing factors and management strategies and the impacts on the target variable to be synoptically judged. Thus the presented regionalization models achieve the role of decision support tools for the planning of forest management at the landscape level. They allow an assessment of the environmental effects of forest management strategies in terms of site sustainability or preservation of water resources in forested catchments.  相似文献   
4.
Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (LC-APCIMS) was employed for the identification of eight lutein monoesters, formed by incomplete enzymatic saponification of lutein diesters of marigold (Tagetes erecta L.) by Candida rugosa lipase. Additionally, the main lutein diesters naturally occurring in marigold oleoresin were chromatographically separated and identified. The LC-MS method allows for characterization of lutein diesters occurring as minor components in several fruits; this was demonstrated by analysis of extracts of cape gooseberry (Physalis peruviana L.), kiwano (Cucumis metuliferus E. Mey. ex Naud.), and pumpkin (Cucurbita pepo L.). The assignment of the regioisomers of lutein monoesters is based on the characteristic fragmentation pattern: the most intense daughter ion generally results from the loss of the substituent (fatty acid or hydroxyl group) bound to the epsilon-ionone ring, yielding an allylic cation. The limit of detection was estimated at 0.5 microg/mL with lutein dimyristate as reference compound. This method provides a useful tool to obtain further insight into the biochemical reactions leading to lutein ester formation in plants.  相似文献   
5.
It has been suggested that lutein and zeaxanthin may decrease the risk for age-related macular degeneration. Surprisingly, oleoresins rich in zeaxanthin are not yet available on the market. Several authors have reported enhanced stability of esterified xanthophylls, so plants containing zeaxanthin esters were investigated to establish valuable sources for the production of durable oleoresins. Liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [LC-(APCI)MS] was used to unequivocally identify zeaxanthin esters of a standard mixture and in several plant extracts. Zeaxanthin esters were quantified on the basis of their respective molecular masses using zeaxanthin for calibration; total zeaxanthin was determined after saponification of aliquots of the extracts. Thus, dried wolfberries (Lycium barbarum), Chinese lanterns (Physalis alkekengi), orange pepper (Capsicum annuum), and sea buckthorn (Hippophae rhamnoides) proved to be valuable zeaxanthin ester sources. The present LC-MS method allows for an even more detailed analysis of zeaxanthin esters than reported previously.  相似文献   
6.
Assembled results from 20 European long-term experiments (LTE), mainly from the first decade of the twenty-first century, are presented. The included LTEs from 17 sites are the responsibility of institutional members of the International Working Group of Long-term Experiments in the IUSS. Between the sites, average annual temperatures differ between 8.1 and 15.3°C, annual precipitation between 450 and 1400 mm, and soil clay contents between 3 and 31%. On average of 350 yield comparisons, combined mineral and organic fertilization resulted in a 6% yield benefit compared with mineral fertilization alone; in the case of winter wheat, the smallest effect was 3%, the largest effect, seen with potatoes, was 9%. All unfertilized treatments are depleted in soil organic carbon (SOC), varying between 0.36 and 2.06% SOC. The differences in SOC in unfertilized plots compared with the respective plots with combined mineral (NPK) and organic (10 t ha?1 farmyard manure) fertilization range between 0.11 and 0.72%, with an average of 0.3% (corresponding to ~15 t ha?1). Consequently, the use of arable soils for carbon sequestration is limited and of low relevance and merely depleted soils can temporarily accumulate carbon up to their optimum C content.  相似文献   
7.
8.
The effect of Diesel fuel on stability of aggregates, plasticity index and shear strength of two soil materials The influence of Diesel fuel contamination on mechanical properties of soil are investigated with regard to the retreatment of materials after a cleaning process. Following aspects are examined in laboratory tests: waterstability of aggregates, plasticity index and shear strength parameter. The used soil materials are mixed samples of a Luvisol (=Bt) and a tidal influenced alluvial clay sediment of a Gley (=Klei). The aggregate stability of Bt material is rising at increasing Diesel fuel contaminations due to a hydrophob effect on the surfaces of the aggregates. This influence cannot be shown for clay material. On the other hand the plasticity index shows a decrease for low Diesel fuel contaminations, because the Diesel fuel acts directly to the particle surfaces. At increasing contaminations these effects are overlayed by increasing viscosity and shear strength of water and Diesel fuel phases or emulsions. The increase in stability of aggregates is not evident in a shear box test. The Diesel fuel shows no influence to angle of internal friction for both investigated materials. On the other hand there is an effect to the cohesion. This phenomenon could be explicated with above mentioned increase in cohesion due to an increase in shear strength and viscosity of a two phase system.  相似文献   
9.
The use of earthworms in monitoring soil pollution by heavy metals Total heavy metal contents (HNO3-soluble) and exchangeable fractions (Ca(NO3)2-soluble) of Pb, Zn and Cd were measured in soils, litter layers and earthworms (dry masses) from forest, arable and pasture sites in a transect of the main wind direction and varying distances (1.5, 5.4, 11.4, 15.6 km) to a lead smelter near Bad Ems, Germany. Additionally, cast materials of Lumbricus terrestris-individuals were collected from the surface of the pasture sites. In the observed area total soil contents of Pb and Cd exceeded the C-level and total contents of Zn the B-level of the “Netherland-list”. Heavy metal contents in soils and earthworms decreased with increasing distance to the smelter. Pb showed the best correlation. Correlation between total contents of Pb and Cd in soils and earthworms were significant (rs = 0.66; p < 0.05 and rs = 0.67; p < 0.01, respectively). The uptake of heavy metals by Lumbricus rubellus, L. terrestris and Aporrectodea caliginosa was metal specific rather than species specific with factors of accumulation being <1 (Pb), 2.7–7.6 (Zn) and 19.5–85.5 (Cd). The heavy metal contents of the observed cast materials signified the different transfer of elements from soil material via earthworm individuals to the faeces. In the cast materials the amounts of Pb were high and the amounts of Zn and Cd were low. This indicates a high accumulation rate for Zn and especially for Cd in the tissues of the observed earthworm individuals. The present data support the necessity of ecotoxicological threshold levels.  相似文献   
10.
Extraction of a copper contaminated soil material by the percolation of an amino acid containing residue hydrolysate. 2. Time course of amino acid elution and input/output balance of amino acids During 16 days an amino acid containing blood meal hydrolysate (amino acid concentration: 188 mMol·L?1) was percolated through a column packed soil material (soil content per column: 4.1 kg dry weight, four parallels). The copper contaminated material (soil type: Typic Udifluvent, soil texture: sandy loam, loamy sand) was sampled from an area formerly used for cultivation of hop (Humulus lupus). Besides the investigation of the copper liberation the experiments aimed to determine the elution dynamic and input/output balance of amino acids (time span for amino acids balance 14 days). In total 11.7 L of hydrolysate, containing 2.2 Mol of amino acids, were introduced into each column. The mean amino acid output with the column effluent was 1.13 Mol. This corresponds to an elution degree of 51.2%, related to the sum of applicated amino acids, and to a mean substance specific elution degree of 48.4% reflecting the elution of 15 compounds. The substance specific elution ranged from 9.6% (serine) to 75.5% (valine). The highest concentrations of serine and threonine were determined in the effluents after two days, whereas the histidine concentration was highest at the last sampling. The differences in the percolation properties of the amino acids are discussed in terms of important retention and elimination processes (biodegradation, ad-/desorption, intercalation).  相似文献   
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