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41.
Gorana Rampazzo Todorovic Michael Stemmer Michael Tatzber Christian Katzlberger Heide Spiegel Franz Zehetner Martin H. Gerzabek 《植物养料与土壤学杂志》2010,173(5):662-670
Despite the importance of soil organic matter (SOM), very few long‐term data concerning soil organic‐C dynamics are available for calibrating and evaluating C models. The long‐term 14C‐turnover field experiment, established in 1967 in Fuchsenbigl, Lower Austria, offers the unique opportunity to follow the fate of labeled C under different crop‐management systems (bare fallow, spring wheat, crop rotation) over a period of more than 35 y. Compared with the crop‐rotation and spring‐wheat treatments, the decline of total organic C was largest in the bare‐fallow treatments, because no significant C input has occurred since 1967. Nonetheless, the decline was not as fast as predicted with the original RothC‐26.3‐model decomposition rate constants. In this work, we therefore calibrated the Roth‐C‐26.3 model for the Pannonian climatic region based on the field‐experiment results. The main adjustment was in the decomposition rate constant for the humified soil C pool (HUM), which was set to 0.009 instead of 0.02 y–1 as determined in the original Rothamsted field trial. This resulted in a higher HUM pool in the calibrated model because of a longer turnover period (111 vs. 50 y). The modeled output based on the calibrated model fitted better to measured values than output obtained with the original Roth‐C‐26.3‐model parameters. Additionally, the original decomposition rate constant for resistant plant material (RPM) was changed from 0.3 to 0.6 y–1 to describe the decomposition of 14C‐labeled straw more accurately. Application of the calibrated model (modified HUM decomposition rate) to simulate removal of crop residues showed that this can entail a long‐term decline of SOM. However, these impacts are strongly dependent on the crop types and on environmental conditions at a given location. 相似文献
42.
Relation between soil organic matter and yield levels of nonlegume crops in organic and conventional farming systems 总被引:2,自引:0,他引:2
Christopher Brock Andreas Fließbach Hans‐Rudolf Oberholzer Franz Schulz Klaus Wiesinger Frank Reinicke Wernfried Koch Bernhard Pallutt Bärbel Dittman Jörg Zimmer Kurt‐Jürgen Hülsbergen Günter Leithold 《植物养料与土壤学杂志》2011,174(4):568-575
The aim of this study was to evaluate the interaction between yield levels of nonleguminous crops and soil organic matter (SOM) under the specific conditions of organic and conventional farming, respectively, and to identify implications for SOM management in arable farming considering the farming system (organic vs. conventional). For that purpose, correlations between yield levels of nonlegume crops and actual SOM level (Corg, Nt, Chwe, Nhwe) as well as SOM‐level development were examined including primary data from selected treatments of seven long‐term field experiments in Germany and Switzerland. Yield levels of nonlegume crops were positively correlated with SOM levels, but the correlation was significant only under conditions of organic farming, and not with conventional farming treatments. While absolute SOM levels had a positive impact on yield levels of nonlegumes, the yield levels of nonlegumes and SOM‐level development over time correlated negatively. Due to an increased demand of N from SOM mineralization, higher yield levels of nonlegumes obviously indicate an increased demand for OM supply to maintain SOM levels. Since this observation is highly significant for farming without mineral‐N fertilization but not for farming with such fertilization, we conclude that the demand of SOM‐level maintenance or enhancement and thus adequate SOM management is highly relevant for crop production in organic farming both from an agronomical and ecological point of view. Under conventional management, the agronomic relevance of SOM with regard to nutrient supply is much lower than under organic management. However, it has to be considered that we excluded other possible benefits of SOM in our survey that may be highly relevant for conventional farming as well. 相似文献
43.
Artemisia vulgaris (mugwort) is a tall (1.0?C2.0 m) high biomass perennial herb which accumulates considerable amounts of metals on contaminated sites. An outdoor pot experiment was conducted on a sandy, slightly alkaline soil of moderate fertility to study the uptake of cadmium and the distribution of Cd in plant tissues of A. vulgaris. Cadmium was applied as CdCl2 (a total of 1 l solution of 0, 10, 50 and 100 mg Cd l?1) to 12-l pots with a height of 25 cm. HNO3- and water-extractable concentrations of Cd were correlated with the applied Cd at 2-cm soil depth, but were not correlated at 20-cm soil depth, suggesting that Cd was either not mobile in the soil or completely taken up by mugwort roots. The Cd concentrations in different organs of A. vulgaris and litter increased with increasing soil contamination. Leaf/soil concentration ratios (BCFs) up to 65.93?±?32.26 were observed. Translocation of Cd to the aboveground organs was very high. The leaf/root Cd concentration ratio (translocation factor) ranged from 2.07?±?0.56 to 2.37 ± 1.31; however, there was no correlation of translocation factors to Cd enrichment, indicating similar translocation upon different soil contamination levels. In summary, A. vulgaris is tolerant to the metal concentrations accumulated, has a high metal accumulating biomass and accumulates Cd up to about 70% in the aboveground parts. Both a high phytoextraction potential and a high value for phytostabilisation would recommend mugwort for phytoremediation. 相似文献
44.
45.
Combinations of thyme, cowslip and liquorice roots are often used in the treatment of upper respiratory tract infections. Therefore the volatile fraction of herbal teas prepared from thyme (Thymus vulgaris) and the effect of combining with cowslip (Primula veris/P. elatior) and liquorice roots (Glycyrrhiza glabra) on the volatiles were analyzed. Volatile compounds were isolated by hydrodistillation and solid phase extraction and analyzed by GC-MS. Thymol was also quantified by HPLC. The total amount of volatiles as well the thymol content was decreased with increasing proportions of cowslip or liquorice in the infusion extracts whereas the proportion of monoterpene hydrocarbons increased. 相似文献
46.
Welche Nutzorganismen sind in Europa für den blologischen Pflanzen- und Gesundheitsschutz verfügbar?
Prof. Dr. J. M. Franz 《Journal of pest science》1984,57(6):105-111
Zusammenfassung Angesichts fehlender Information über die kommerzielle Verfügbarkeit in Europa von Biopräparaten (auf der Basis von Mikroorganismen einschl. der Viren) und von nützlichen Metazoen für biologische Maßnahmen zur Unterdrückung von Schadorganismen wurde an die amtlichen Stellen, ausnahmsweise an Einzelexperten in folgenden Ländern eine Umfrage gerichtet: Frankreich, Großbritannien, Italien, Österreich, Rumänien, Jugoslawien, Schweden, die Schweiz, die Niederlande, Finnland und Bundesrepublik Deutschland. Die Ergebnisse werden in 2 Teilen als ein Momentbild des Zustandes Anfang 1984 vorgelegt. Im Begleittext wird für die Annahme einer Europäischen Zulassungsordnung für Biopräparate plädiert (die als Entwurf bereits vorliegt), um Zeit und Geld zu sparen. Zwischen den einzelnen Ländern bestehen sehr große Unterschiede bezüglich der Verfügbarkeit biotischer Agentien für biologische Verfahren. Einige vielversprechende neue Entwicklungen werden kurz in der Hoffnung vorgestellt, daß sie stimulierend wirken. Allen Kollegen, die bei der Umfrage geholfen haben, sei besonders gedankt.
Mit 2 Tabellen 相似文献
Which beneficial organisms are available in Europe for biological plant and health protection
In view of the lack of information concerning the commercial availability in Europe of biopreparations (based on microorganisms including viruses) as well as of beneficial metazoa for biological control of pest organisms, an inquiry was started for the following countries: France, Great Britain, Italy, Austria, Rumania, Yugoslavia, Sweden, Switzerland, the Netherlands, Finland and Germany Fed. Rep. Results are presented as a momentary picture of the situation in early 1984. A plead is made for the acceptance of an European protocol for registration of biopreparations (which has already been drafted) in order to save money and time. There are great differences between countries in the availability of biotic agents for biological control. Some very promising new developments are briefly reviewed and considered to act in a stimulating way. Thanks are due to those colleagues who helped to obtain the information here presented.
Mit 2 Tabellen 相似文献
47.
Felix Gugerli Rolf Gall Franz Meier Beat Wermelinger 《Forest Ecology and Management》2008,256(3):405-409
The dynamics of a recent outbreak of the spruce bark beetle (Ips typographus) in Switzerland was ruled by a devastating winter storm in 1999 and the drought and heat of the summer 2003. Starting from a similar level of population sizes, estimated as the rate of infested growing stock, beetle populations increased differently in magnitude and time among different regions in Switzerland. Accordingly, we expected local or regional genetic differentiation as a result of such repeated population expansion/breakdown dynamics. We analyzed 5 nuclear microsatellites of spruce bark beetles sampled from pheromone traps at 30 locations distributed over Switzerland. Our genetic results did not indicate any sign of population differentiation, structure, isolation by distance, or recent bottlenecks. This complete lack of genetic structure suggests that spruce bark beetles are highly mobile, precluding the formation of a spatial structure at neutral molecular markers. Thus, this molecular–genetic approach does not allow us to discriminate among regional gene pools and to identify the origin of expanding beetle populations. 相似文献
48.
Crototropone (3-hydroxy-5,6-dimethoxy-2-methylcyclohepta-2,4,6-trien-1-one) was isolated from roots of Croton zehntneri. The structure was established by spectroscopic methods. 相似文献
49.
The paper presents the results of a study in the region Dübener Heide (Central Germany) testing the suitability of field measurements of magnetic susceptibility for the detection of historical fly-ash deposition. The measurements supported the verification of historically documented deposition zones along an emission gradient. Mean values, standard deviation, and coefficient of variation can be used to characterize the former deposition zones, although the study revealed several problems, which will be the subject of future work: (1) the volume susceptibility measurements used in the study do not allow the calculation of the actual fly-ash amount stored in the soil and thus must be calibrated with correction factors from laboratory measurements; and (2) measurements in regions with similar conditions but without fly-ash deposition are needed to obtain reference values for the natural range of magnetic susceptibility. 相似文献
50.
Tropical regions are currently undergoing remarkable rates of land use change accompanied by altered litter inputs to soil. In vast areas of Southern Ecuador forests are clear cut and converted for use as cattle pastures. Frequently these pasture sites are invaded by bracken fern, when bracken becomes dominant pasture productivity decreases and the sites are abandoned. In the present study implications of invasive bracken on soil biogeochemical properties were investigated. Soil samples (0-5 cm) were taken from an active pasture with Setaria sphacelata as predominant grass and from an abandoned pasture overgrown by bracken. Grass (C4 plant) and bracken (C3 plant) litter, differing in C:N ratio (33 and 77, respectively) and lignin content (Klason-lignin: 18% and 45%, respectively), were incubated in soils of their corresponding sites and vice versa for 28 days at 22 °C. Unamended microcosms containing only the respective soil or litter were taken as controls. During incubation the amount of CO2 and its δ13C-signature were determined at different time intervals. Additionally, the soil microbial community structure (PLFA-analysis) as well as the concentrations of KCl-extractable C and N were monitored. The comparison between the control soils of active and abandoned pasture sites showed that the massive displacement of Setaria-grass by bracken after pasture abandonment was characterized by decreased pH values accompanied by decreased amounts of readily available organic carbon and nitrogen, a lower microbial biomass and decreased activity as well as a higher relative abundance of actinomycetes. The δ13C-signature of CO2 indicated a preferential mineralization of grass-derived organic carbon in pasture control soils. In soils amended with grass litter the mineralization of soil organic matter was retarded (negative priming effect) and also a preferential utilization of easily available organic substances derived from the grass litter was evident. Compared to the other treatments, the pasture soil amended with grass litter showed an opposite shift in the microbial community structure towards a lower relative abundance of fungi. After addition of bracken litter to the abandoned pasture soil a positive priming effect seemed to be supported by an N limitation at the end of incubation. This was accompanied by an increase in the ratio of Gram-positive to Gram-negative bacterial PLFA marker. The differences in litter quality between grass and bracken are important triggers of changes in soil biogeochemical and soil microbial properties after land use conversion. 相似文献