Applicability of ELISA for determination of metsulfuron‐methyl in soil samples

An immunoassay (ELISA) for analysis of metsulfuron‐methyl was evaluated as a method for quantifying residues in soil. Soil samples were extracted with phosphate buffered saline (PBS), PBS + acetone (80 + 20 by volume) or ammonium carbonate and were analyzed with both ELISA and LC‐MS. A tendency for the ELISA to overstimate the metsulfuron‐methyl content was noted and matrix effects were pronounced, particularly in PBS + acetone or ammonium carbonate extracts. Dilution of extracts before analysis improved the situation but reduced the sensitivity of the assay. Using light standard concentrations it was shown that the extracts in PBS on dilutions exhibited a curve parallel with the standard curve, indicating no significant interference due to matrix effects. A working range of 10–250 ng litre⁻¹ was found for ELISA on this type of extracts. © 2000 Society of Chemical Industry     

Joint action of natural and synthetic photosystem II inhibitors

The inhibitory action on photosystem II of four sorgoleone analogues, isolated from Sorghum bicolor (L) Moench, and two synthetic inhibitors, diuron and bentazone, was tested by measuring oxygen evolution of thylakoid membranes. The inhibition of oxygen evolution for mixtures of inhibitors was compared with the Additive Dose Model (ADM). ADM assumes that, at a defined response level, the effect of a mixture of inhibitors can be unambiguously expressed by the potency of either of the inhibitors applied separately. The slope of the logistic dose-response curves differed between the inhibitors; sorgoleone analogues had the steepest and bentazone the shallowest slope. The difference in slopes makes the interpretation of the isoboles less general and may reflect the differences in the interaction between the natural and the synthetic inhibitors with the binding site. The results suggest that there may be some limitation to ADM, namely that compounds with the same site of action might have different response curves if their mechanism of binding is different. The joint action of inhibitors follows ADM at I₅₀ . Therefore, the inhibitors can replace each other in any mixture ratio, based on the relative potencies of the pure inhibitors, without changing each other's effect on oxygen evolution. The joint action at I₂₀ and I₈₀ sometimes diverged from ADM. © 1999 Society of Chemical Industry     

The apparent prevalence of skin lesions suspected to be human-inflicted in Danish finishing pigs at slaughter

Skin lesions on pigs inflicted by humans compromise animal welfare and are the subject of increased public and political attention in Denmark. Systematic surveillance of such skin lesions was enforced in April 2010 at all Danish pig abattoirs, through the recording of meat inspection Code 904 for the presence of skin lesions suspected to be human inflicted. The objectives of the present study were to (a) estimate the apparent prevalence of Code 904s at the pig and herd owner level; (b) characterise the distribution of deliveries with pigs demonstrating a Code 904; (c) characterise the distribution of herd owners with repeated Code 904 recordings; and (d) determine the developments in Code 904 prevalence over time in Danish finishing pigs in the period from May 1, 2010 to September 30, 2013.     

Resorptive tooth root lesions in the Malayan tapir (Tapirus indicus)

Facial abscessation and osteomyelitis due to dental disease is commonly seen in the Malayan tapir (Tapirus indicus), but little is known about the prevalence or etiology of these lesions. To determine the prevalence of dental ailments, 56 skulls and mandibles of deceased Malayan tapirs were visually and radiographically evaluated. Dental lesions were scored according to severity, and individuals were classified according to their age (juvenile/ young adult/adult) and origin (captive/free ranging). All of the lesions identified were of a resorptive nature. seemingly originating at the cementoenamel junction and burrowing towards the center of the tooth. Overall, 27% of the investigated skulls presented radiolucent dental lesions. The prevalence among captive animals was 52% (13/25), while only 6% (2/31) of the free-ranging tapirs had dental lesions. The second, third, and fourth premolars and first molar were the teeth most commonly affected, and the mandibular teeth were more often involved than the maxillary dentition. This study demonstrates a high prevalence of resorptive dental lesions in captive Malayan tapirs and provides a strong indication that age and captivity are significant risk factors in the development of these lesions. Dental disease, Malayan tapir, radiology, resorptive lesions, Tapirus indicus.     

Structure liming enhances aggregate stability and gives varying crop responses on clayey soils

It has been suggested that liming can improve soil structure and thereby decrease losses of particles and associated nutrients. In this study, two types of structure lime, slaked lime (Ca(OH)₂) and a mixed product of calcium carbonate (CaCO₃) and slaked lime (Ca(OH)₂), were applied at three different rates in field trials on clayey soils (23%–40% clay). A combination of primary tillage and structure liming was also studied, in a split-plot trial on a clayey soil (25% clay). Aggregate (2–5?mm) stability, measured as reduction in turbidity (which is strongly correlated with losses of particulate phosphorus), was significantly increased with the highest application rates of both structure lime products. Aggregate size distribution was also improved with structure lime, creating a finer tilth in the seedbed. Yield response to structure lime was not consistent, with both negative and positive responses over the four-year study period. Positive yield responses can possibly be attributed to the finer tilth preventing evaporation in two dry growing seasons. Negative yield responses were probably an effect of impaired phosphorus availability associated with limited precipitation in May-July in 2011 and 2013. Two years after liming, soil pH levels were significantly elevated in plots with the highest application rate of structure lime, whereas no significant increases were found three years after liming. However, a lingering effect of liming was still detectable, as manganese concentration in barley grain was significantly lower in plots with the highest application rates of both structure lime products in the fourth study year. These results indicate that structure liming can be used as a measure to mitigate phosphorus losses from clayey soils, thereby preventing eutrophication of nearby waters. However, the yield response was varying and unpredictable and thus further investigations are needed to determine the circumstances in which field liming can act efficiently not only to prevent phosphorus losses, but also to ensure consistent yield increases.     

Suitability of common models to estimate hydrology and diffuse water pollution in North-eastern German lowland catchments with intensive agricultural land use

Various process-based models are extensively being used to analyze and forecast catchment hydrology and water quality. However, it is always important to select the appropriate hydrological and water quality modeling tools to predict and analyze the watershed and also consider their strengths and weaknesses. Different factors such as data availability, hydrological, hydraulic, and water quality processes and their desired level of complexity are crucial for selecting a plausible modeling tool. This review is focused on suitable model selection with a focus on desired hydrological, hydraulic and water quality processes (nitrogen fate and transport in surface, subsurface and groundwater bodies) by keeping in view the typical lowland catchments with intensive agricultural land use, higher groundwater tables, and decreased retention times due to the provision of artificial drainage. In this study, four different physically based, partially and fully distributed integrated water modeling tools, SWAT (soil and water assessment tool), SWIM (soil and water integrated model), HSPF (hydrological simulation program– FORTRAN) and a combination of tools from DHI (MIKE SHE coupled with MIKE 11 and ECO Lab), have been reviewed particularly for the Tollense River catchment located in North-eastern Germany. DHI combined tools and SWAT were more suitable for simulating the desired hydrological processes, but in the case of river hydraulics and water quality, the DHI family of tools has an edge due to their integrated coupling between MIKE SHE, MIKE 11 and ECO Lab. In case of SWAT, it needs to be coupled with another tool to model the hydraulics in the Tollense River as SWAT does not include backwater effects and provision of control structures. However, both SWAT and DHI tools are more data demanding in comparison to SWIM and HSPF. For studying nitrogen fate and transport in unsaturated, saturated, and river zone, HSPF was a better model to simulate the desired nitrogen transformation and transport processes. However, for nitrogen dynamics and transformations in shallow streams, ECO Lab had an edge due its flexibility for inclusion of user-desired water quality parameters and processes. In the case of SWIM, most of the input data and governing equations are similar to SWAT but it does not include water bodies (ponds and lakes), wetlands and drainage systems. In this review, only the processes that were needed to simulate the Tollense River catchment were considered, however the resulted model selection criteria can be generalized to other lowland catchments in Australia, North-western Europe and North America with similar complexity.     

Common vole (Microtus arvalis) ecology and management: implications for risk assessment of plant protection products

Common voles (Microtus arvalis) are common small mammals in some European landscapes. They can be a major rodent pest in European agriculture and they are also a representative generic focal small herbivorous mammal species used in risk assessment for plant protection products. In this paper, common vole population dynamics, habitat and food preferences, pest potential and use of the common vole as a model small wild mammal species in the risk assessment process are reviewed. Common voles are a component of agroecosystems in many parts of Europe, inhabiting agricultural areas (secondary habitats) when the carrying capacity of primary grassland habitats is exceeded. Colonisation of secondary habitats occurs during multiannual outbreaks, when population sizes can exceed 1000 individuals ha^?1. In such cases, in‐crop common vole population control management has been practised to avoid significant crop damage. The species' status as a crop pest, high fecundity, resilience to disturbance and intermittent colonisation of crop habitats are important characteristics that should be reflected in risk assessment. Based on the information provided in the scientific literature, it seems justified to modify elements of the current risk assessment scheme for plant protection products, including the use of realistic food intake rates, reduced assessment factors or the use of alternativee focal rodent species in particular European regions. Some of these adjustments are already being applied in some EU member states. Therefore, it seems reasonable consistently to apply such pragmatic and realistic approaches in risk assessments for plant protection products across the EU. © 2013 Society of Chemical Industry     

Plant species richness and diversity in urban and peri-urban gardens of Niamey,Niger

Urban and peri-urban agriculture (UPA) significantly contributes to food and nutritional security of urban dwellers in many African countries. Economic and demographic pressures often lead to transformation of subsistence-oriented traditional homegardens into commercial production units. Such transformation is claimed to result in decreasing plant diversity, particularly of local species. A study was therefore undertaken in 51 gardens of Niamey, Niger, to assess the factors determining plant diversity and the suitability of UPA for in situ conservation of plant genetic resources. In each garden, the number and abundance of all human-used plant species were determined, and species density, Shannon index and Shannon evenness were calculated. In the 51 surveyed gardens, a total of 116 plant species were cultivated, most of them for the production of fruits or vegetables. Annual vegetables dominated, particularly exotic species grown for sale. In the cold season, an average of 14 species were cultivated per garden, the Shannon index was 0.96 and evenness was 0.39. Commercial gardens had a species richness similar to that of subsistence gardens, but a lower evenness (P < 0.005), caused by the dominance of a few vegetable species. Gardens of immigrants had a lower Shannon index than those of members of the local Djerma ethnic group. Stepwise multiple regression analysis showed significant influence of various variables on plant species richness and diversity parameters: garden size (richness and Shannon index), ethnicity of the gardener (richness and evenness), gender of the gardener and cash-oriented production (evenness), household size (richness) and garden possession status (Shannon index). Cluster analysis revealed the existence of five garden types. The highest species richness and diversity, particularly of perennial and local species, was found in large, peri-urban, commercial gardens managed by relatively wealthy, elderly gardeners with large families and a regular non-agricultural income.     

Losses of essential mineral nutrients by polishing of rice differ among genotypes due to contrasting grain hardness and mineral distribution

The effect of different polishing techniques on loss of mineral elements from rice grains was quantified using a panel of indica and tropical japonica genotypes, previously classified as differing in ease of polishing. Gradients in mineral elements across the bran-endosperm interface were quantified using micro-scaled precision abrasive polishing in combination with inductively coupled plasma mass spectrometry and synchrotron X-ray fluorescence microscopy. Frictional polishing, similar to that of commercial mills, i.e. 8–10% loss of grain weight, reduced the concentration of Fe, Mg, P, K and Mn by 60–80% in all genotypes. Following gentler polishing (3–5% weight loss), genotypes classified as difficult to polish showed smaller decreases in Fe, Mg, P, K and Mn compared to genotypes classified as easy to polish. The concentration of other elements, e.g. Zn, S, Ca, Cu, Mo and Cd, showed comparable reductions (<30%) irrespective of polishing technique or ease of polishing. The different patterns of polishing losses of minerals reflected their distribution within the grain. Five-fold differences in the reduction of Zn concentration during polishing were observed for different genotypes which started with similar Zn concentrations in the unpolished grain, thus showing clear potential for selecting genotypes with reduced polishing losses of Zn.