Water dispersible clay in calcareous soils of southwestern Spain

Water dispersible clay (WDC) is a good indicator of the risk of soil erosion by water and the consequent losses of nutrients and contaminants in overland flow. We measured the content and studied the properties of WDC in 26 samples of calcareous Xeralfs, Xerepts and Xererts of southwestern Spain collected from fields under different crop and tillage management; the soils ranged widely in total clay content (60–455 g kg^− 1), calcium carbonate equivalent (CCE) (< 1–559 g kg^− 1) and active calcium carbonate equivalent (ACCE; 2–135 g kg^− 1), and were poor in organic carbon and soluble salts. The WDC content was determined by shaking 10 g of soil in 1 L of simulated rainwater for 4 hours. Non-carbonate WDC contents were found to be strongly correlated with the total clay content of the soils and ranged from 1 to 92 g kg^− 1 soil (mean = 29 g kg^− 1), the non-carbonate WDC/total clay ratio ranging from 0.01 to 0.29 (mean = 0.12). Based on regression analyses, illite was more dispersible than smectite and iron oxides decreased dispersion of clay. Carbonate WDC contents ranged from 1 to 27 g kg^− 1 (mean = 8 g kg^− 1) and were averaged one third the non-carbonate WDC contents; also, they were strongly correlated with the soil ACCE. WDC was rich in phosphorus (P) relative to the bulk soil. The enrichment ratio (ER) for total P (i.e. the ratio of total P in WDC to total P in soil) ranged from 0.2 to 29 (mean = 5) and was inversely related to the total clay content. On average, about one tenth of the soil total P was exported in the WDC and about one fifth of the total P in WDC was in the form of bicarbonate-extractable P (i.e. relatively soluble or ‘labile’ P). Part of the P in WDC seemingly occurred as metal phosphate particles formed by reaction of P fertilizers with soil. In summary, significant amounts of P can be exported via WDC, even though the proportion of total clay that is water dispersible is substantially lower in these soils than in cultivated soils of other semiarid regions.     

Mapping within-field variability in wheat yield and biomass using remote sensing vegetation indices

Precision Agriculture - This paper explored the ability of remote sensing (RS) and meteorological data to map the variability of yield/biomass in cultivated wheat (Triticum aestivum). The...     

Bioavailability of ferulic acid is determined by its bioaccessibility

Epidemiological studies have linked whole grain consumption to prevention of several chronic diseases. Whole grain is a source of important phytochemicals, such as ferulic acid (FA). FA is the most abundant phenolic and major contributor to the in vitro antioxidant capacity of wheat grain. Several studies have reported highly variable results on FA bioavailability (0.4–98%). The binding of FA to polysaccharides may limit its bioavailability. Therefore, our study aimed at monitoring release features of FA during gastrointestinal (GI) transit. This was termed bioaccessibility. The bioaccessibility of FA was studied from different wheat fractions and breads with the use of a dynamic in vitro system that simulates the upper GI transit and digestion. The results showed low bioaccessibility of FA from the wheat fractions and breads (<1%). However, the bioaccessibility was high when free FA was added to flour (∼60%). The bioaccessibility of FA appeared to be determined by the percentage of free FA. In wheat grain, most of FA is bound to arabinoxylans and other indigestible polysaccharides restricting its release in the small intestine. New processing developments should be considered to increase free FA in the cereal matrix in order to improve its bioavailability and systemic health effect.     

Valorization of Organic Wastes to Reduce the Movement of Priority Substances Through a Semiarid Soil

In this work, we examined the effect of two different organic wastes, composted sheep manure and coir, on the sorption, persistence, and mobility of three pesticides (alachlor, chlorfenvinphos, and chlorpyrifos) included as priority substances in European Directive 2013/39/EU. With this aim, leaching studies were conducted using disturbed soil columns filled with a typical agricultural soil (hipercalcic calcisol) from a semiarid area (southeastern Spain) to determine their potential for groundwater pollution. The three compounds were found in leachates of unamended soil although in different proportions: 53% (alachlor), 9% (chlorfenvinphos), and 6% (chlorpiryfos). The addition of organic wastes significantly increased the sorption of the studied pesticides. As a consequence, the half-lives of the studied pesticides were higher in amended than in unamended soils. A marked reduction of the amount recovered in leachates was observed in the amended soils, except for chlorpiryfos, whose recoveries barely changed. According to their potential groundwater pollution calculated as the groundwater ubiquity score (GUS) index, alachlor and chlorfenvinphos show medium leachability while chlorpiryfos is unlikely to leach.     

Evaluation of a novel nested PCR for the routine diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV)

Laboratory diagnosis of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) usually involves both viruses, as the clinical signs are similar and coinfection may occur. Serological methods may not represent an accurate diagnosis: maternal antibodies or cross-reactions may give false positive results to FIV, and false negative results may occur in latent FeLV status, or in certain FIV infection stages. A nested polymerase chain reaction (PCR) technique was designed to detect FeLV, FIV and feline endogenous retrovirus simultaneously. The detection of endogenous sequences was considered indicative of successful DNA extraction. The technique was used to diagnose FIV and FeLV in the blood cells of 179 cats. The kappa value with the serological data was 0.69 for FeLV and 0.87 for FIV. The joint detection of FeLV and FIV by this novel nested PCR is sensitive, specific, fast and convenient, and its applicability for clinical diagnosis is promising, as the direct evidence of the presence of the virus is more realistic than the indirect data provided by the serological detection.     

Using flower strips to promote green lacewings to control cabbage insect pests

Habitat management improves biological control by increasing the abundance and fitness of natural enemies through the provision of floral resources along field edges or between crops. Among the natural enemies reliant on flower resources, green lacewings often stand out due to their abundance, predation capacity and polyphagy. We evaluated the impact of tailored flower strips on the enhancement of natural enemies, especially green lacewings, in three organic cabbage (Brassica oleracea) farms in Southern Sweden. Insects were sampled from the flower strips, and cabbage pests and predators were visually recorded in the crop. In a laboratory assay, the pollen feeding preferences of Chrysoperla carnea (Stephens, 1836) were evaluated in a dual-choice test. The pollen consumed by the Chrysopidae was extracted from laboratory and field specimens, then quantified and identified. Flower strips were found to attract predators and parasitoids, whose abundance increased as flowers bloomed. Cabbage plants next to the flower strips showed lower pest infestation as compared to cabbage plant control, although no significant differences were observed in the number of predators. Chrysopidae used flower strips as feeding, reproduction and shelter sites and mainly consumed pollen from Phacelia tanacetifolia Benth. Under laboratory conditions, C. carnea showed a preference for P. tanacetifolia and Coriandrum sativum L. pollen over Borago officinalis L. and Fagopyrum esculentum Moench. We show that tailored flower strips could be an efficient tool for enhancing beneficial arthropods and should be considered in integrated pest management for cabbage crops.

     

Spatial road disturbance index (SPROADI) for conservation planning: a novel landscape index, demonstrated for the State of Brandenburg, Germany

The expansion of roads, and the subsequent changes to the surrounding landscape not only lead to landscape fragmentation but also have been shown to be a key driver of biodiversity loss and ecosystem degradation. Local declines of species abundance as well as changes in animal behaviour have drawn attention to wider ecosystem effects including altered species composition and a degradation of ecosystem functioning. However, methods for measuring and quantifying the distribution and environmental impacts of roads are not yet fully developed. We present a new technique for assessing the potential impacts of roads on biodiversity using a spatial road disturbance index (SPROADI). The index is calculated from three sub-indices: traffic intensity as a measure of traffic volume per time and space; vicinity impact, which is the assessment of edge effect of roads on adjacent habitats (the road-effect zone); and fragmentation grade, which provides an indication of the degree to which the landscape is intersected by roads. SPROADI was then tested using data from the Federal State of Brandenburg in north-eastern Germany. A sensitivity analysis was carried out on the results to assess the robustness of the index. The findings revealed expected patterns of high road disturbance in urban and peri-urban landscapes surrounding Berlin. Less obvious were the high levels of road density and impacts in forest plantations across the southern region of Brandenburg, and low levels of road disturbance in agricultural crop lands of the north-western region. Results were variable for areas under some form of protection. The only national park displayed substantially lower SPROADI values in contrast to the surrounding non-protected areas whilst other protected area categories, which were landscape conservation areas and nature parks, revealed SPROADI values that were equally high as those for non-protected areas. The results of this study demonstrate the strengths and potential applications of SPROADI as a quantitative means for identifying low-traffic areas in the context of conservation and sustainable transport planning.     

Fertilisation with biosolids in a silvopastoral system established with Pseudotsuga menziesii (Mirb.) Franco in Galicia (NW Spain)

Agroforestry Systems - In Europe, sewage sludge has to be stabilised before its use as fertiliser in agricultural land. Stabilisation processes can cause differences in the concentration of heavy...     

Visceral leishmaniasis with cardiac involvement in a dog: a case report

A dog presented with cutaneous nodules, enlarged lymph nodes and oedema in limbs, face and abdomen. The diagnosis of visceral leishmaniasis was established by identification of Leishmania amastigotes within macrophages from skin and popliteal lymph node biopsies. At necropsy, lesions were found in different organs, but it was particularly striking to observe large areas of pallor in the myocardium. Histological examination revealed an intense chronic inflammatory reaction in many organs, and numerous macrophages were found to contain amastigote forms of Leishmania. The inflammatory reaction was especially severe in the heart, where large areas of the myocardium appeared infiltrated with huge numbers of mononuclear immune cells, causing cardiac muscle atrophy and degeneration. Despite the severe inflammation, the number of parasitized macrophages was low in the myocardium, as revealed by immunohistochemical staining of Leishmania amastigotes. Because cardiac involvement is not usually described in this condition, this dog represents a very rare case of canine visceral leishmaniasis with affection of the myocardium.