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31.
The effect of cereal straw with added mineral N fertilization on crop yields, N uptake, total organic C content and hot water soluble C content in topsoil and on the relationships between organic C content in topsoil and organic matter balance was evaluated in a long-term field experiment established in 1966. The effect of straw plus mineral N fertilization was similar to the effect of farmyard manure (FYM) in the dry matter yields and also in the N uptake by plants. The effect of straw and mineral N fertilization on the organic C accumulation in soil was inferior to the effect of farmyard manure. Relationships between organic matter balance and total organic C content in the topsoil was positive and statistically significant. A favourable effect of mineral NPK fertilization on the C sequestration to soil was related to the effect of FYM fertilization. 相似文献
32.
Tomas Losak Jaroslav Hlusek Jiri Martinec Jiri Jandak Monika Szostkova Radek Filipcik 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):543-550
Abstract Due to continuous single nitrogen fertilization, we hypothesized a built-up deficiency of micronutrients in crops that would limit plant growth and crop quality. In 2-year field experiments using urea-N fertilized grain maize (Zea mays L.), hybrid KWS 2376 at 0, 120 and 240 kg N ha?1 crop uptake of Zn, Mn, Cu and Fe was studied at DC 32, DC 61 and in the grain harvested. Micronutrient contents at DC 32 stage – 1st node (aboveground phytomass) and DC 61 – flowering (ear leaf) were all at levels indicative of adequate micronutrient supply to the crop. At both sampling occasions the Fe:Zn and Fe:Mn ratios were adequate implying that Fe did not inhibit the uptake of Zn and Mn. The application of nitrogen increased the Fe content at the 1st sampling in both years; in the second year the same was also the case for the Zn content. Nitrogen nutrition increased the contents of Mn and Fe at the 2nd sampling only in year 2; in the other treatments no changes were observed in the micronutrient contents. Micronutrient correlations in the grain were discovered between Zn and Mn contents and between Fe and Mn contents. In the second year the highest N-rate significantly increased the Fe and Zn content of the grain compared with the lower rates of nitrogen fertilization. Grain yields were not affected by the rate of nitrogen and ranged between 13.65 and 14.34 t ha?1 (1st year) and between 13.68 and 14.18 t ha?1 (2nd year). Nitrogen fertilization did not reduce the content of micronutrients in the plant or grain of maize. It is evident that the continuous single use of N fertilization so far has not resulted in a micronutrient deficiency of the plants limiting the nutrient density of the grain or reducing its quality. 相似文献
33.
Lenka Zarubova Miloslav Zouhar Pavel Novy Ondrej Douda Jiri Skuhrovec 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):89-93
Biopesticides derived from plants have recently received increasing interest as an alternative to conventional chemicals suitable for integrated pest management and organic farming. In this study, Citrus sinensis (Osbeck) essential oil was tested for its potential for wheat protection against Oulema melanopus (L.). The chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Twenty-four compounds were identified in the oil among which d-limonene was a predominant component, followed by myrcene, α-pinene, linalool, sabinene, decanal, and other minor components. Direct contact toxicity assay showed the effectiveness of the essential oil against O. melanopus larvae causing the mortality of 85% during 48 hours. The persistence study revealed high dissipation rate of the oil from treated plants, whereas concentrations lower than 0.01 g/kg were detected by GC-MS 5 min after the application of the oil, suggesting its environmental and food safety. These results, together with previous literature reports reviewed in this study, indicate the great potential of the C. sinensis essential oil for future use in crop protection against insect pests. 相似文献
34.
Real-time controlled pesticide application requires a fast reacting system, enabling continuous variation of pesticide type
and concentration based on a control signal. Direct injection systems meet the requirements for such application; however
there are significant differences in the response time and quality of single system designs. This article discusses the complex
of problems in direct injection systems in connexion with real-time control and proposes optimisations of system parts in
order to reduce the response time and improve the quality of the process. The system response time was reduced to 160 ms for
1% output concentration by optimization of the control process, injection assembly and mixing chamber design. 相似文献
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The influence of different pH values, ranging from 4.0 to 7.0, on the formation of sulfur volatiles in the Maillard reaction was studied using a model system with [13C5]xylose, cysteine, and thiamin. The use of 13C-labeled xylose allowed, by analysis of the mass spectra, volatiles that incorporated xylose carbons in the molecule from other carbon sources to be discerned. For 2-furaldehyde and 2-furfurylthiol, which were favored at low pH, the labeling experiments clearly indicated that xylose was the exclusive carbon source. On the other hand, xylose was virtually not involved in the formation of 3-mercapto-2-butanone, 4,5-dihydro-2-methyl-3-furanthiol, and 5-(2-hydroxyethyl)-4-methylthiazole, which apparently stemmed from thiamin degradation. Both xylose and thiamin seemed to significantly contribute to the formation of 2-methyl-3-furanthiol, 3-mercapto-2-pentanone, and 2-mercapto-3-pentanone, and therefore different formation pathways must exist for each of these molecules. In general, the pH determined strongly which volatiles were formed, and to what extent. However, the relative contribution of xylose to the C-skeleton of a particular compound changed only slightly within the investigated pH range, when both xylose and thiamin were involved in the formation. 相似文献
40.
ABSTRACT: Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae accounts for serious economic losses in the pig farming industry worldwide. We examined here the immunogenicity and protective efficacy of the recombinant type IV fimbrial subunit protein ApfA as a single antigen vaccine against pleuropneumonia, or as a component of a multi-antigen preparation comprising five other recombinant antigens derived from key virulence factors of A. pleuropneumoniae (ApxIA, ApxIIA, ApxIIIA, ApxIVA and TbpB). Immunization of pigs with recombinant ApfA alone induced high levels of specific serum antibodies and provided partial protection against challenge with the heterologous A. pleuropneumoniae serotype 9 strain. This protection was higher than that engendered by vaccination with rApxIVA or rTbpB alone and similar to that observed after immunization with the tri-antigen combination of rApxIA, rApxIIA and rApxIIIA. In addition, rApfA improved the vaccination potential of the penta-antigen mixture of rApxIA, rApxIIA, rApxIIIA, rApxIVA and rTbpB proteins, where the hexa-antigen vaccine containing rApfA conferred a high level of protection on pigs against the disease. Moreover, when rApfA was used for vaccination alone or in combination with other antigens, such immunization reduced the number of pigs colonized with the challenge strain. These results indicate that ApfA could be a valuable component of an efficient subunit vaccine for the prevention of porcine pleuropneumonia. 相似文献