The phosphorus status of German cropland—An inventory of top‐ and subsoils

Background : In search for more sustainable crop production, the subsoil has recently come into focus as considerable reservoir of nutrients and water. Aims : Dimensions of subsoil phosphorus (P) reserves are yet largely unknown but crucial for identifying regions suitable to include subsoil into sustainable management strategies. Methods : We analyzed stocks of total and plant‐available (calcium acetate lactate‐extractable) P in 96 representative soil profiles of German arable land down to 1 m depth. Results : We found that the German arable soils stored, on average, 8 t ha^?1 of total P, of which nearly 500 kg ha^?1 were readily plant‐available. Notably, one third of plant‐available P was located below the plow layer and one fifth even at depths below 0.5 m. The depth gradients of plant‐available P stocks were affected more by major reference soil group than by texture. Generally, Chernozem but also Anthrosol, Gleysol and Fluvisol exhibited the largest P stocks in German cropland. The contribution of plant‐available P to total P stocks was larger in sandy and extremely acidic (pH < 4.5) soils compared with more fine‐grained and slightly acidic to alkaline soils, possibly because fertilization compensated for overall lower total P stocks at these sites. Generally, the more P was stored in topsoils, the more P was stored also in subsoils. Conclusions : A hypothetical crop utilization of 10% from plant‐available P stocks and 0.1% from total P stocks from shallow subsoil could compensate for P fertilization by ca. 8 kg ha^?1, but the rate of plant‐available P replenishment in subsoil likely remains the crucial factor for the role of subsoil P stocks in crop nutrition. Generally, the large P reserves found in subsoil could act as an ‘insurance' system for crops.     

MHC class I peptides as chemosensory signals in the vomeronasal organ

The mammalian vomeronasal organ detects social information about gender, status, and individuality. The molecular cues carrying this information remain largely unknown. Here, we show that small peptides that serve as ligands for major histocompatibility complex (MHC) class I molecules function also as sensory stimuli for a subset of vomeronasal sensory neurons located in the basal Gao- and V2R receptor-expressing zone of the vomeronasal epithelium. In behaving mice, the same peptides function as individuality signals underlying mate recognition in the context of pregnancy block. MHC peptides constitute a previously unknown family of chemosensory stimuli by which MHC genotypic diversity can influence social behavior.     

Habitat, human pressure, and social behavior: Partialling out factors affecting large-scale territory extinction in an endangered vulture

Extinctions are often the result of multiple factors that are difficult to disentangle and so methods for identifying simple and combined types of extinctions are valuable for both basic and applied ecology. We applied a modification of variance partitioning and a hierarchical partitioning analysis to test several hypotheses that attempt to explain the recent large-scale disappearance of Egyptian Vulture breeding territories in Spain. Our aim was to identify and then separate the simple (or pure) from the combined effects of habitat features, human pressure, and the social behavior of the species on the risk of extinction from a territory while controlling for spatial autocorrelation. Deviance partitioning showed that a complex mix of factors is significantly related to the disappearance of more than 400 territories throughout Spain. Abandoned territories were located in areas that are isolated from other conspecific territories and far from communal roost sites. In addition, these territories were found in places where there is a lack of natural habitats, high habitat fragmentation and reduced habitat diversity, and where food availability seems to be low and the illegal use of poison to control predators is a common practice. Deviance partitioning also showed an important spatial component in the probability of extinction. Abandoned territories were not randomly distributed; rather, they were aggregated in extinction ‘hotspots’, mainly related to food availability and human pressure. Deviance partitioning turned out to be an useful tool for identifying the relative contribution of a variety of factors - and their combined effects - associated with an extinction process. The deviance explained by each factor must be interpreted, however, in the context of a good knowledge of the life history of the species. Hierarchical partitioning can help rank conservation priorities and, by using as an objective criterion the relative weight of each independent variable that could be effectively managed for conservation, may provide wildlife managers with a means of saving funds and optimizing action plans.     

High alcohol consumption in Germany: results of the German National Health Interview and Examination Survey 1998

OBJECTIVE: To analyse the alcohol consumption behaviour of the German adult population, with a focus on the characteristics of persons drinking more than the tolerable upper alcohol intake level (TUAL) of 10-12 g day(-1) for healthy adult women and 20-24 g day(-1) for healthy adult men. DESIGN AND SETTING: For the German National Health Interview and Examination Survey 1998, a representative sample of free-living adults was drawn. A total of 7124 participants were interviewed comprehensively about their sociodemographic background, lifestyle and eating habits including alcohol consumption. SUBJECTS: A sub-sample of 4030 women and men, 18-79 years old, who were involved in the integrated German Nutrition Survey. RESULTS: About 16% of women and 31% of men had mean alcohol consumption above the TUAL. Among other factors, the inclination to exceed the TUAL was related to middle-age, high socio-economic status, smoking and use of soft drugs. Among both women and men, a high proportion of persons drinking above the TUAL was observed among those consuming low amounts of soft drinks, fruit, poultry, milk products, bread and cake/biscuits. Women preferred to drink wine, whereas men preferred to drink beer. CONCLUSIONS: Many Germans have an alcohol consumption level above the TUAL and thus are supposed to be at increased risk for alcohol-associated diseases.     

The assessment of sediment screening risk in Venice Lagoon and other coastal areas using international sediment quality guidelines

Background, Aims and Scope  A number of studies carried out in recent years have shown the presence of a wide range of contaminants in the Venice Lagoon. It is important to have a good understanding of the ecological quality of Venice Lagoon sediments, in order to: i) define and locate areas where a threat to the environment is present and therefore an intervention is needed (i.e. in situ assessment and management); and ii) define sustainable and environmentally correct ways of managing sediments which are to be dredged for navigational purposes or in relation to other interventions (i.e., ex situ management). Methods  To examine how various regional and international SQGs ‘classed’ screening risk in Venice Lagoon sediments, data on median contaminant levels in surface sediments in Venice Lagoon resulting from a literature review were compared to a range of local and international sediment quality guidelines (SQGs). Then data on sediment contaminant levels in various areas and sub-basins of Venice Lagoon (main Lagoon, Porto Marghera and Venice City Canals) and in other regional and international transitional and coastal ecosystems with various levels of human impact (urbanization and industrialization) were evaluated based upon a selected consensus-based SQG. Finally, screening sediment quality for all of Venice Lagoon was mapped and contoured, relative to this consensus-based SQG and briefly compared with direct toxicity measurement through a battery of bioassays. Results  SQGs allow the sediment areas to be put in terms of potential, or screening, risk. Although there were some differences depending upon which specific SQGs were applied, the Venice SQGs and other international SQGs provided the same general picture of screening risk in Venice Lagoon despite geographic differences. Venice Lagoon South has the lowest screening risk levels, Venice Lagoon Central/North has the highest (and is nearest to the Porto Marghera and Venice City Canals sites). Discussion  The Venice Lagoon sediments have hazard quotients on the low end of the range of moderately urbanized and industrialized sites and higher than background case studies reviewed. Hg levels in the Venice Lagoon were generally higher than equivalent sites, while other contaminants were either equivalent or lower. In Porto Marghera (PM) and Venice City Canals (VC), for many contaminants of interest, PM, and for some, VC sediments have the highest levels of any case study reviewed. Ranges are high, so in all cases, remedial or disposal decisions should be based upon site-specific (and preferably tiered) data. Conclusions  The use of hazard quotients makes it possible to compare screening risks due to different mixes of contaminants within and between sites, but results should be interpreted with caution. How these sites rank when compared to some of the other highly industrialized sites depends upon how data are synthesized and communicated. Actual risk must be evaluated using a weight of evidence (WOE) approach, as site-specific bioavailability and background levels will differ both regionally and internationally. Recommendations and Perspectives  Whilst there are subtle differences, the current Venice sediment classifications (A, B and C) ‘performed’ in a similar manner to SQGs in similar classes, suggesting that regions of Venice Lagoon would not be classified much differently if other SQGs such as TEL, ERL, PEL, ERM or AET were adopted. The Italian sediment quality objectives, on the other hand, are significantly more conservative than any other SQGs examined, with the exception of the Flemish Reference values. A number of European nations are considering criteria based upon contaminant levels in relatively pristine modern sites, or based upon derivations of historical (pre-anthropogenic) contaminant levels. When used as a standard, such an approach lacks discriminating power, designating almost all sediments within an urbanized or industrialized region as of concern, or even, in many cases, mandating action or prohibiting various management approaches in a large percentage of sediments. While generally based upon the laudable desire to return sites to unimpacted levels, there is a risk that overprotective criteria have the opposite effect: by designating too large a percentage of sediments as requiring management or control, limited resources may be improperly allocated. Which set of SQGs is most ‘appropriate’ for the Venice Lagoon sediments depends upon the questions being asked. However, the Venice classifications are currently being used as pass-fail criteria, without consideration of site-specific conditions. The fact that they performed similarly to SQGs in similar classes suggests that any work to develop more site-specific SQGs (with the same general decision classes) would probably not make much difference in how sediments were ultimately classified and managed unless the fundamental approach was changed from a pass-fail to a tiered and WOE approach integrated in a comprehensive decision framework. For Venice Lagoon, and for other regions, although SQGs should be developed with care, in a scientifically defensible and risk-based manner, an equally or more important issue to be addressed is their role in overall decision frameworks. ESS-Submission Editor: Dr. Marc Babut (marc.babut@cemagref.fr)     

Managing contaminated sediments

While remediation and storage of contaminated dredged materials is a key issue at harbour sites, there is another type of sediment pollution problem, which mainly originates from large-scale dispersion of contaminants in flood-plains, dike foreshores and polder areas. In recent years, catastrophic cases of sediment contaminations have occurred in connection with the failure of tailing dams from mines. Unlike problems related to conventional polluted sites, the risks here are primarily connected with the transporting and depositing of contaminated solids in a catchment area, especially in downstream regions. A special example demonstrating the dispersion of highly contaminated sediments in a large catchment area will be shown from the so-called Chemistry Triangle of the upper Elbe River system, Germany. The Spittelwasser area, situated there, was chosen by the organisers of the international conference ConSoil 2000 for a case comparison and four expert teams from Denmark, Germany, the Netherlands and the UK were invited to participate in this Case Study. Evaluation of the plan was done by members of the networks of NICOLE (Network for Industrially Contaminated Land) and CLARINET (Contaminated Land Rehabilition Network). In the study of the German team, five major groups of technical measures have been identified by the environmental authorities to be discussed in relation to the Spittelwasser case or for similar problem solutions in contaminated flood-plain areas. The team came to the conclusion that none of these techniques would be applicable as an individual measure. Instead, a stepwise approach combining different monitoring techniques and remediation measures was proposed. These would include point excavations of critical material, promotion of plant growth as an element for stabilising the soil and flood sediments, as well as the installation of sediment traps. At the Spittelwasser site, investigations are planned on the effects of natural attenuation processes of organic and inorganic contaminants in flood-plain sediments and soils. In the practice of this concept, non-destructive, ‘intrinsic’ bonding mechanisms and their temporal development have thus far found much less recognition compared to destructive processes such as biological degradation. Yet these so-called ‘diagenetic’ effects, which apart from chemical processes involve an enhanced mechanical consolidation of soil and sediment components by compaction, loss of water, and mineral precipitations in the pore space, may induce a quite essential reduction of the reactivity of solid matrices [see Part I ‘Improving Chemical and Biological Criteria’ (JSS - Journal of Soils and Sediments, Vol 1, No 1, pp 30-36)]. Part IV ‘Subaqueous Storage/Capping of Dredged Material’ will be published in JSS No. 4 (December issue).     

Modellanlage zur Bestimmung von Ammoniakverlusten aus organischen und mineralischen Düngern unter kontrollierten Bedingungen

A model system for the determination of ammonia losses from organic and mineral fertilizers under controlled conditions A closed-dynamic model was developed for the continuous registration of losses of ammonia. NH₃ escaping from the soil surface is introduced to an acid trap. The resulting increase in pH is equivalent to the amount of NH₃ and is recorded by an automatic data recorder. Wind velocity in this system can be adjusted between 100 and 400 L air/h, which corresponds to a 12 to 40-fold total air exchange per minute. Temperature can be regulated between +5°C and +30°C. In addition, air humidity can be controlled. The testing of the model revealed deviations of maximally 0.6% between measured pH value and destillation. The average recovery amounted to 97.2%.     

Silicon uptake by wheat: Effects of Si pools and pH

Silicon (Si), although not considered essential, has beneficial effects on plant growth which are mostly associated with the ability to accumulate amorphous (phytogenic) Si, e.g., as phytoliths. Phytogenic Si is the most active Si pool in the soil–plant system because of its great surface‐to‐volume ratio, amorphous structure, and high water solubility. Despite the high abundance of Si in terrestrial biogeosystems and its importance, e.g., for the global C cycle, little is known about Si fluxes between soil and plants and Si pools used by plants. This study aims at elucidating the contribution of various soil Si pools to Si uptake by wheat. As pH affects dissolution of Si pools and Si uptake by plants, the effect of pH (4.5 and 7) was evaluated. Wheat was grown on Si‐free pellets mixed with one of the following Si pools: quartz sand (crystalline), anorthite powder (crystalline), or silica gel (amorphous). Silicon content was measured in aboveground biomass, roots, and soil solution 4 times in intervals of 7 d. At pH 4.5, plants grew best on anorthite, but pH did not significantly affect Si‐uptake rates. Total Si contents in plant biomass were significantly higher in the silica‐gel treatment compared to all other treatments, with up to 26 mg g^–1 in aboveground biomass and up to 17 mg g^–1 in roots. Thus, Si uptake depends on the conversion of Si into plant‐available silicic acid. This conversion occurs too slowly for crystalline Si phases, therefore Si uptake from treatments with quartz sand and anorthite did not differ from the control. For plants grown on silica gel, real Si‐uptake rates were higher than the theoretical value calculated based on water transpiration. This implies that Si uptake by wheat is driven not only by passive water flux but also by active transporters, depending on Si concentration in the aqueous phase, thus on type of Si pool. These results show that Si uptake by plants as well as plant growth are significantly affected by the type of Si pool and factors controlling its solubility.     

Measurement of respiratory system compliance and respiratory system resistance in healthy dogs undergoing general anaesthesia for elective orthopaedic procedures

Objective The aim of this study was to investigate normal values for the dynamic compliance of the respiratory system (Crs) and respiratory system resistance (Rrs) in mechanically ventilated anaesthetized dogs.Study design Prospective clinical study.Animals Forty healthy dogs undergoing elective orthopaedic surgery. Body weight was (mean ± SD) 26.8 ± 10.7 kg (range: 1.9–45.0 kg), age 4.7 ± 2.9 years (range: 0.1–10.6 years).Methods Dogs were premedicated with acepromazine and methadone administered intramuscularly and anaesthesia induced with propofol intravenously. After endotracheal intubation the dog's lungs were connected to an appropriate breathing system depending on body weight and isoflurane in oxygen administered for maintenance of anaesthesia. The lungs were ventilated mechanically with variables set to maintain normocapnia (end‐tidal carbon dioxide concentration 4.7–6.0 kPa). Peak inspiratory pressure, Crs, Rrs, tidal volume, respiratory rate and positive end‐expiratory pressure were recorded at 5, 30, 60, 90 and 120 minutes after start of mechanical ventilation. Cardiovascular variables were recorded at time of collection of respiratory data.Results General additive modeling revealed the following relationships: Crs = [0.895 × body weight (kg)] + 8.845 and Rrs = [?0.0966 × body weight (kg)] + 6.965. Body weight and endotracheal tube diameter were associated with Crs (p <0.001 and p =0.002 respectively) and Rrs (p = 0.017 and p =0.002 respectively), body weight being linearly related to Crs and inversely to Rrs.Conclusion and clinical relevance Body weight was linearly related to Crs while Rrs has an inverse linear relationship with body weight in mechanically ventilated dogs. The derived values of Crs and Rrs may be used for monitoring of lung function and ventilation in healthy dogs under anaesthesia.