Relationships between long-term trends of air temperature,precipitation, nitrogen nutrition and growth of coniferous stands in Central Europe and Finland     

Karl Heinz Mellert  Jörg Prietzel  Ralf Straussberger  Karl Eugen Rehfuess  Hans Peter Kahle  Pedro Perez  Heinrich Spiecker 《European Journal of Forest Research》2008,127(6):507-524

Height growth of 19 Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) stands in Germany, Austria and Finland, for which long-term records of foliar nutrient levels were available, was assessed retrospectively by stem analyses and compared with data from regionally applied yield tables as references. Gridded historical time series of monthly temperature and precipitation were used to characterise the meteorologic conditions at the sampling sites. Climate parameters were tested against height growth in period 1950–2000, and needle N content was tested against height growth for the periods where N measurements were available by means of graphical comparison, as well as simple and multiple regression analyses with the aim to get evidence for causes of possible growth acceleration. Trends of referenced height increment of six out of nine Scots pine stands in Germany were positive during the observation period, and improved N nutrition appeared to be the most important driving factor for this growth acceleration. The variation of precipitation—exhibiting no consistent and uniform long-term temporal trend during the observation period—in contrast seems to be mainly responsible for the interannual fluctuation of height growth. We were not able to detect any general statistical influence of temperature parameters on height growth, although they generally increased. The referenced height growth of three Finnish pine stands slightly decreased during the observation period and there was no indication of a significant improvement of their N supply. Among four Norway spruce stands investigated in Germany and Austria, referenced height increment also increased in three cases; there was again some evidence that improved N nutrition was the stimulating factor. At three study sites in Finland, however, referenced height growth of this species decreased at least from 1985 onwards, whereas mostly no significant trends in N nutrition or precipitation were identified. These differences observed between species and regions are discussed in detail.  相似文献   

Willow stands as an alternative method for the reduction of leachate at contaminated sites — numerical investigations     

Petra Kahle  Christian Criegee  Bernd Lennartz 《植物养料与土壤学杂志》2002,165(4):501-505

The commonly used multiple‐liner‐system of modern top sealings of contaminated sites is expensive and in many cases (minor hazardousness of pollutants), not necessary. As an alternative, we investigated the performance of willow stands as the only measure to reduce percolating soil water and therewith pollutant transport to underlying ground water resources. It is well accepted that willows have a high water demand and may considerably reduce percolation. On the basis of experimentally determined soil physical properties of a landfill site, we performed water balance calculations with the physically based HYDRUS‐code and a simple bucket approach. The 20 yr annual leachate rate for bare soil was calculated to vary from 336 (HYDRUS) to 451 mm yr^—1 (bucket‐model). Willows were able to reduce the annual leachate to 146 (HYDRUS) and 186 mm yr^—1 (bucket‐model), indicating their great performance compared to a grass‐ or beechwood cover. However, legal regulations (TASi) in Germany cannot be met with the proposed method. In minor hazardous cases, official authorities may accept willow stands as an alternative system for protection.  相似文献   

Soil carbon dioxide and nitrous oxide emissions during the growing season from temperate maize‐soybean intercrops     

Lisa Dyer  Maren Oelbermann  Laura Echarte 《植物养料与土壤学杂志》2012,175(3):394-400

The Argentine Pampa is one of the major global regions for the production of maize (Zea mays L.) and soybean (Glycine max L. [Merr.]), but intense management practices have led to soil degradation and amplified greenhouse‐gas (GHG) emissions. This paper presents preliminary data on the effect of maize‐soybean intercrops compared with maize and soybean sole crops on the short‐term emission rates of CO₂ and N₂O and its relationship to soil moisture or temperature over two field seasons. Soil organic carbon (SOC) concentrations were significantly greater (p < 0.05) in the maize sole crop and intercrops, whereas soil bulk density was significantly lower in the intercrops. Soil CO₂ emission rates were significantly greater in the maize sole crop but did not differ significantly for N₂O emissions. Over two field seasons, both trace gases showed a general trend of greater emission rates in the maize sole crop followed by the soybean sole crop and were lowest in the intercrops. Linear regression between soil GHG (CO₂ and N₂O) emission rates and soil temperature or volumetric soil moisture were not significant except in the 1:2 intercrop where a significant relationship was observed between N₂O emissions and soil temperature in the first field season and between N₂O and volumetric soil moisture in the second field season. Our results demonstrated that intercropping in the Argentine Pampa may be a more sustainable agroecosystem land‐management practice with respect to GHG emissions.  相似文献   

Orientierende untersuchungen zum einfluss des miscanthusanbaus auf ausgewählte eigenschaften verschiedener böden     

Petra Kahle  Barbara Boelcke  Steffen Zacharias 《Archives of Agronomy and Soil Science》2013,59(3):163-174

In vorliegenden Beitrag werden für 4 verschiedene Standorte in Deutschland die Bodeneigenschaften unter 4‐ bis 6‐jährigen Miscanthusbeständen als Grundlage für ein komplex angelegtes Untersuchungsprogramm vorgestellt und diskutiert. Die Varianten “mit Miscanthus” zeichnen sich durch geringfügig erhöhte Humusgehalte gegenüber “ohne Miscanthus” aus, verbunden mit weitreichenden Auswirkungen auf andere relevante Bodenmerkmale. Erkennbar werden Beeinflussungen der Wasserretention, der Porosität und der Lagerungsdichte.  相似文献   

USING SEMI‐AUTOMATED SEGMENTATION OF COMPUTED TOMOGRAPHY DATASETS FOR THREE‐DIMENSIONAL VISUALIZATION AND VOLUME MEASUREMENTS OF EQUINE PARANASAL SINUSES     

Markus Brinkschulte  Astrid Bienert‐Zeit  Matthias Lüpke  Maren Hellige  Carsten Staszyk  Bernhard Ohnesorge 《Veterinary radiology & ultrasound》2013,54(6):582-590

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three‐dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2–25 years, were analyzed by the use of separate semi‐automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi‐automated segmentation of CT‐datasets improved understanding of this anatomically challenging region.  相似文献   

The impact of climate change on the growth of tropical agroforestry tree seedlings     

Shahira Esmail  Maren Oelbermann 《Agroforestry Systems》2011,83(2):235-244

Several studies have been conducted on the response of crops to greater concentrations of atmospheric CO₂ (CO₂ fertilization) as a result of climate change, but only few studies have evaluated this effect on multipurpose agroforestry tree species in tropical environments. The objectives of this study were to quantify differences in growth parameters and in leaf carbon (C) and nitrogen (N) concentrations of Cedrela odorata L. and Gliricidia sepium (Jacq.) Walp. seedlings under current ambient temperature (32°C daytime, 22°C night time) and CO₂ (360 ppm) (AMB); CO₂ fertilization (800 ppm, 32°C daytime, 22°C night time) (_fCO₂); elevated ambient temperature (360 ppm, 34°C daytime, 25°C night time) (TEMP); and a combination of elevated temperature (32°C daytime, 22°C night time) and CO₂ fertilization (800 ppm) (TEMPx_fCO₂). Results showed significant differences (P < 0.05) in seedling growth parameters (seedling height, number of stem leaves, leaf area ratio, shoot and root biomass, and shoot/root ratio) between treatments for both tree species. The greatest increases in growth parameters occurred in the TEMP and TEMPx_fCO₂ treatments compared to the AMB treatment for both tree species. However, growth parameters were significantly lower (P < 0.05) in the _fCO₂ treatment compared to that of the AMB treatment. Leaf N concentration was 1.1 to 2.1 times lower (P < 0.05) in all treatments when compared to current ambient conditions (AMB) in both tree species, but no significant changes in leaf C concentrations were observed. Results from our study suggested that _fCO₂ had the greatest negative impact on tree growth parameters, and leaf N concentrations were affected negatively in all treatments compared to current ambient conditions. It is expected that such changes in growth parameters and plant N content may impact the long-term cycling of nutrients in agroforestry systems.  相似文献   

Auswirkungen eines 10-jährigen Miscanthusanbaus auf ausgewählte Eigenschaften eines Mineralbodens in Nordostdeutschland     

P. Kahle  L. Belau  & B. Boelcke 《Journal of Agronomy and Crop Science》2002,188(1):43-50

Effects of 10 years of Miscanthus cultivation on different properties of mineral soil in North-east Germany
The effects of 4–10 years of Miscanthus cultivation on different soil properties was investigated at Klein Markow (Mecklenburg-Pommerania, Germany) in variants with and without Miscanthus between 1994 and 2000. Soil containing Miscanthus showed higher concentrations of organic carbon (C_org) (+0,29 %) and total nitrogen (N_t) (+0,03 %) and consequently an increased storage of soil organic matter (SOM) (+15,5 t ha^–1) as a result of high amounts of leaves, roots and rhizomes. With regard to concentrations of C_org, cation exchange capacity, porosity and water retention significantly increased, while the wet and bulk density decreased in Miscanthus variants. The concentration of C_org and storage of SOM were increased significantly during the experimental period of Miscanthus treatments. The mineralization of the organic soil compounds which developed was comparable with those of the SOM. The reintegration of the Miscanthus area into a crop rotation system was possible only after the last harvest in February and seed of winter rape in August of the same year. The application of Glyphosat and the later shading by rape stands led to failure of the Miscanthus cultivations.  相似文献   

Ethanol organosolv pretreatment of softwood (Picea abies) and sugarcane bagasse for biofuel and biorefinery applications     

Swarnima Agnihotri  Ingvild A. Johnsen  Maren S. Bøe  Karin Øyaas  Størker Moe 《Wood Science and Technology》2015,49(5):881-896

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Einfluß unterschiedlicher Gehalte an organischer Bodensubstanz auf das Konsistenzverhalten verschiedener Mineralbodensubstrate     

Petra Kahle  Hermann Kretschmer 《植物养料与土壤学杂志》1994,157(5):393-396

Effect of organic matter content on the consistency of several mineral substrates The effect of organic matter content on the consistency of soils different in texture was investigated. The shifts of the values of the consistency limits towards higher moisture contents are explained by different organic matter contents. The consistency limits of plasticity and liquidity. were significantly dependent on the content of organic matter.  相似文献   

Cadmium in Fagus sylvatica L. trees and seedlings: Leaching,uptake and interconnection with transpiration     

Jürgen Hagemeyer  Henning Kahle  Siegmar-W. Breckle  Yoav Waisel 《Water, air, and soil pollution》1986,29(4):347-359

Most of the airborne Cd-polluted particles which eventually precipitate in forest regions remain on the surface of the tree leaves and do not penetrate into the plants' live tissues. Such pollutions can be removed from the leaves by cation exchange or can be washed off with water of low pH. Acid rains and acid soils have contributed very much to the solubilization of Cd and to its transformation into an available ionic form which is later absorbed by tree roots. ^115mCd uptake by young beech trees (Fagus sylvatica L.) seems to be positively correlated with the concentrations of the applied solutions as well as with the duration of the exposure. Low environmental pH increases the rate of ^115mCd uptake. High or low transpiration had no apparent effect on root absorption of Cd, but exposure of beech trees to a Cd(NO₃)₂ solution reduced their rates of transpiration after very few days of treatment.  相似文献