Inter‐specific variability in organic nitrogen uptake of three temperate grassland species

We tested the inter‐specific variability in the ability of three dominant grasses of temperate grasslands to take up organic nitrogen (N) in the form of amino acids in soils of differing fertility. Amino acid uptake was determined by injecting dual labeled glycine‐2‐¹³C‐¹⁵N into the soil, and then measuring the enrichment of both ¹³C and ¹⁵N in plant tissue after 50 hours. We found enrichment of both ¹³C and ¹⁵N in root and shoot material of all species in both soils, providing first evidence for direct uptake of glycine. We show that there was considerable inter‐specific variability in amino acid uptake in the low fertility soil. Here, direct uptake of amino acid was greater in the grass Agrostis capillaris, which typically dominates low fertility grassland, than Lolium perenne, which inhabits more fertile sites. Direct uptake of amino acid for Holcus lanatus. was intermediate between the above two species. Unlike in the low fertility soil, there was no difference in uptake of either ¹³C or ¹⁵N by grasses in the high fertility soil, where uptake of mineral N is thought to be the major mechanism of N uptake of these grasses. Overall, our findings may contribute to our understanding of differences in competitive interactions between grasses in soils of different fertility status.     

Living in a Dusty World: Airborne Dust as a Key Factor for Alpine Lakes

For a long time studies on precipitation and lake-water chemistry have focussed on the deposition of strong acids. Dust in snow and rain was analyzed much less intensively, but recent findings suggest that it may be the missing link which explains why many low-alkalinity lakes in the Alps and the Pyrenees did not become acidic and nutrient levels are seasonally high, whereas lakes in areas which are rarely influenced by dust depositions, for instance in Scandinavia, have acidified. Beside being a dominant factor for nutrient inputs to oceans, rain forests and remote lakes, dust can also play a major role in global warming and cooling, and it may significantly contribute to soil formation at mountain sites in the Mediterranean. I suggest that future changes in dust deposition and warming will be key factors for the development of alpine lakes.     

Optimized LC/MS/MS analysis of morphine and codeine in poppy seed and evaluation of their fate during food processing as a basis for risk analysis

The opiate alkaloids present in poppy seed intended for use in food recently have raised major concerns. An efficient method for routine analysis of morphine and codeine using liquid chromatography in combination with tandem mass spectrometry on a triple quadrupole instrument (LC/MS/MS) was therefore developed. The optimal sample preparation was found to be cold extraction of 10 g of unground poppy seed with 30 mL of methanol containing 0.1% acetic acid for 60 min shaken at 250 rpm. The fate of morphine during food processing was also studied. All experiments led to a significant reduction of morphine and codeine. For poppy cake only 16-50% of the morphine was recovered, and in poppy buns at the highest temperature (220 degrees C) only 3% of the original morphine content was found. Ground poppy seed showed significantly lower recoveries than untreated seed. Morphine elimination during food processing has to be taken into account in the current discussion about its maximum limits in poppy seed.     

Extent and Management of Low pH Soils in Ghana

A review of soil acidity problems with regards to causes, extent and management in Ghana shows that the extent of soil acidity has changed within a period of 2–3 decades. In the 1970s' soil acidity was a major problem in the Western region and the lowlands. Oxisols and Ultisols are common soils found in this area. However, anthropogenic causes have augmented natural causes resulting in more low pH soils. Soil acidity has therefore become a serious problem throughout the country. Anthropogenic causes identified include general agronomic practices such as tillage, use of mineral fertilizers and continuous cultivation. Rates of 1–2 t ha⁻¹ lime on ultisols and oxisols in Ghana are more than adequate to meet the calcium demands and sufficient to neutralize residual acidity of any nitrogen fertilizer. Addition of organic amendments on low pH soils was also found to be beneficial and resulted in increased yields. The adoption of the "sawah" technology for lowland rice production has also resulted in improved water management, increased nutrient availability and significant increases in rice yields.     

Chronic toxicity of fenoxycarb to the midge Chironomus riparius after exposure in sediments of different composition

Background, aim, and scope  

Fenoxycarb is an insect growth regulator widely used to control a variety of pests. As a juvenile hormone analogue, it interacts with the natural hormones involved in insect development, inhibiting metamorphosis to the adult stage. Adverse effects of fenoxycarb on non-target organisms have been repeatedly observed and its rapid dissipation from water to the organic fraction of the sediment is known. The aim of this work was to investigate the impact of fenoxycarb on the development of sediment-dwelling larvae of the midge Chironomus riparius after exposure to spiked sediment.     

Estimation of transmission parameters of a fluoroquinolone-resistant Escherichia coli strain between pigs in experimental conditions

Antimicrobial resistance is of primary importance regarding public and animal health issues. Persistence and spread of resistant strains within a population contribute to the maintenance of a reservoir and lead to treatment failure. An experimental trial was carried out to study the horizontal transmission of a fluoroquinolone-resistant Escherichia coli strain from inoculated to naïve pigs. All naïve contact pigs had positive counts of fluoroquinolone-resistant E. coli after only two days of contact. Moreover, re-infections of inoculated pigs caused by newly contaminated animals were suspected. A maximum likelihood method, based on a susceptible-infectious-susceptible (SIS) model, was used to determine the transmission parameters. Two transmission levels were identified depending on the quantity of bacteria shed by infected individuals: (i) low-shedders with bacterial counts of resistant E. coli in the faeces between 5*10³ and 10⁶ CFU/g (β_L = 0.41 [0.27; 0.62]), (ii) high shedders with bacterial counts above 10⁶ CFU/g (β_H = 0.98 [0.59; 1.62]). Hence, transmission between animals could be pivotal in explaining the persistence of resistant bacteria within pig herds.     

Bridging the Gap between Centrally Defined Policies and Local Decisions – Towards more Sensitive and Creative Rural Landscape Management

European policies and instruments such as the Common Agricultural Policy (CAP) and many instruments for nature and landscape conservation in Europe have for some decades been dominated by centralisation and standardisation. This paper shows that this has led to the neglect of contextual and place-related approaches and an unnecessarily high degree of over-simplification. Recently, as a reaction to this over-simplification, diversity and specific character has been particularly stressed in many European and national strategies for rural landscapes and conservation, but the processes of simplification still continue. Using examples from mixed agriculture and forestry landscapes in Portugal, Slovenia and Sweden, this paper aims to contribute to understanding the gap between centrally defined strategies for rural landscapes and awareness and management practices at local level. The three countries are situated at the outer fringes of Europe, and are complementary with their different degrees of urbanisation, forest distribution and tree-richness in the agricultural landscapes. Furthermore, the aim is to show how local landscape management is driven and to identify factors contributing to a better use of public policies through a participatory process with visions for the future. Systems of landscape classifications such as landscape character assessment often recognise the specific character of these landscapes, but have so far achieved very little for the preservation of their locally specific values, nor have they contributed to the development and the creation of new visions for future management. Such systems could contribute much more if they could be opened to adaptation on a more local scale in communication-led management planning.     

A rapid and simple method for determining fungicide resistance in Botrytis

A simple test based on the germination of conidia of Botrytis on agar media augmented with various fungicides has been developed. Average concentrations causing a 50% reduction of germ-tube growth (EC₅₀) of highly sensitive isolates were determined on 1% malt extract agar (thiophanate-methyl 0.090 ppm; iprodione 0.566 ppm; fludioxonil 0.026 ppm; fenhexamid 0.144 ppm), 1% malt extract agar with 100 ppm salicyl hydroxamic acid (QoI fungicides, viz. trifloxystrobin 0.009 ppm; pyraclostrobin 0.013 ppm; azoxystrobin 0.087 ppm), 0.5% yeast extract agar (boscalid 0.069 ppm) and 0.5% sucrose agar (cyprodinil 0.053 ppm). In order to detect different levels of resistance against these various fungicides, two discriminatory concentrations were identified for each compound. A routine assay method was developed in which drops of a conidial suspension harvested directly from diseased plant material or sporulating cultures were incubated on each of 20 different agar media. Because of a very short time-span of 24–48 h between sample collection and evaluation of results, field-specific information on the occurrence, frequency and types of resistance of Botrytis against common botryticides in soft-fruit production may be generated prior to the main fungicide spray season at blossom time.