Aggregate strength and mechanical behaviour of a sandy loam soil under long-term fertilization treatments

Current concern for soil quality has stimulated research on soil biological and chemical properties. In contrast, the mechanical behaviour of soil is somewhat neglected. We have examined the effects on soil mechanical properties of more than 100 years of contrasting fertilization employing three treatments from the Askov long‐term experiment: UNF (unfertilized), NPK (mineral fertilized) and AM (animal manured). We have measured tensile strength of aggregates when air‐dry and when adjusted to ?10, ?30 and ?100 kPa pressure potential. Four aggregate size classes were investigated (1–2, 2–4, 4–8 and 8–16 mm diameter). Soil fragmentation was characterized in the field using a drop‐shatter test. Bulk soil strength was determined in the field using a shear vane and a torsional shear box. Soil texture, pH, cation exchange capacity and microbial biomass were measured. The unfertilized soil has little soil organic matter and microbial biomass and is dense. Its aggregates were strong when dry and weak when wet. In contrast, the manured soil had strong aggregates when wet and rather weak ones when dry. The NPK soil generally had intermediate properties. The differences between the soils when dry seem to be related to differences in dispersible clay content, whereas the differences when wet are related to differences in the amount of organic binding and bonding material. The optimal water content for tillage as well as the tolerable range in water content was largest in the manured soil and smallest in the unfertilized soil. Our results indicate that soil mechanical properties should be measured over a range of water regimes to determine the effects of various long‐term fertilization treatments.     

Turnover of grain legume N rhizodeposits and effect of rhizodeposition on the turnover of crop residues

The turnover of N derived from rhizodeposition of faba bean (Vicia faba L.), pea (Pisum sativum L.) and white lupin (Lupinus albus L.) and the effects of the rhizodeposition on the subsequent C and N turnover of its crop residues were investigated in an incubation experiment (168 days, 15 °C). A sandy loam soil for the experiment was either stored at 6 °C or planted with the respective grain legume in pots. Legumes were in situ ¹⁵N stem labelled during growth and visible roots were removed at maturity. The remaining plant-derived N in soil was defined as N rhizodeposition. In the experiment the turnover of C and N was compared in soils with and without previous growth of three legumes and with and without incorporation of crop residues. After 168 days, 21% (lupin), 26% (faba bean) and 27% (pea) of rhizodeposition N was mineralised in the treatments without crop residues. A smaller amount of 15–17% was present as microbial biomass and between 30 and 55% of mineralised rhizodeposition N was present as microbial residue pool, which consists of microbial exoenzymes, mucous substances and dead microbial biomass. The effect of rhizodeposition on the C and N turnover of crop residues was inconsistent. Rhizodeposition increased the crop residue C mineralisation only in the lupin treatment; a similar pattern was found for microbial C, whereas the microbial N was increased by rhizodeposition in all treatments. The recovery of residual ¹⁵N in the microbial and mineral N pool was similar between the treatments containing only labelled crop residues and labelled crop residues + labelled rhizodeposits. This indicates a similar decomposability of both rhizodeposition N and crop residue N and may be attributable to an immobilisation of both N sources (rhizodeposits and crop residues) as microbial residues and a subsequent remineralisation mainly from this pool.Abbreviations C or N_dec C or N decomposed from residues - C or N_mic microbial C or N - C or N_micres microbial residue C or N - C or N_min mineralised C or N - C or N_input added C or N as crop residues and/or rhizodeposits - dfr derived from residues - dfR derived from rhizodeposition - Ndfr N derived from residues - NdfR N derived from rhizodeposition - N_loss losses of N derived from residues - SOM soil organic matter - WHC water holding capacity     

Benz(a)pyrene input and occurrence in a marine area affected by refinery effluent

The load of benz(a)pyrene in a marine coastal area in the vicinity of a town and an oil refinery has been estimated. The levels of benz(a)pyrene in refinery effluent, municipal waste water, urban run-off, rivers, and atmospheric fall-out have been determined. In the study area the major source was atmospheric fall-out. The levels of benz(a)pyrene in sediments and in mussels,Mytilus edilus have been determined. The possible removal of benz(a)pyrene from the study area has been evaluated. This includes sedimentation, degradation, and advective water transport.     

A new genus and two new species of Anteroporidae (Cestoda: Lecanicephalidea) from the darkspotted numbfish, Narcine maculata (Torpediniformes: Narcinidae), off Malaysian Borneo

The cestode fauna of the darkspotted numbfish, Narcine maculata (Shaw) (Torpediniformes: Narcinidae), from Malaysian Bomrneo was examined for the first time. This work resulted in the discovery of a new genus and two new species of Anteroporidae (Lecanicephalidea). Sesquipedalapex comicus gen. n., sp. n. was erected on the basis of the peculiarities of its scolex, in particular its possession of an extremely long apical modification of the scolex proper, which readily distinguishes it from the other genus in the family. The genus is also distinct in its possession of acetabula that are in the form of suckers, rather than bothridiate in form. This species was found to deeply embed its elongate apical structure for much of its length within the intestinal mucosa, provoking a papilliform expansion of the outer wall of the spiral intestine at the site of attachment. The second new species, Anteropora klosmamorphis sp. n., is readily distinguished from its congeners on the basis of testis number and bothridial shape. Both new species are hyperapolytic. The diagnosis of Anteroporidae is amended to accommodate both new taxa. This increases the total number of genera in the family to two, and the total number of species to five.     

Prolonged activated prothromboplastin time and breed specific variation in haemostatic analytes in healthy adult Bernese Mountain dogs

Coagulation tests are often performed in dogs suspected of haemostatic dysfunction and are interpreted according to validated laboratory reference intervals (RIs). Breed specific RIs for haematological and biochemical analytes have previously been identified in Bernese Mountain dogs, but it remains to be determined if breed specific RIs are necessary for haemostasis tests. Activated prothromboplastin time (aPTT), prothrombin time (PT), selected coagulation factors, D-dimers, fibrinogen, von Willebrand factor and thromboelastography (TEG) were analyzed in healthy Bernese Mountain dogs using the CLSI model. Three analytes (aPTT, TEG [MA] and TEG [G]) were different according to the CLSI model. For aPTT the new RI was markedly different (0-100s). Whereas the new intervals for TEG (MA) and TEG (G) may be due to breed related biological variation, the cause of the prolonged RI for aPTT is at present uncertain.     

Dietary divercin modifies gastrointestinal microbiota and improves growth performance in broiler chickens

1. The aim of the present study was to investigate the effects of dietary administration of a divercin AS7 liquid preparation on broiler chicken performance, nutrient digestibility, counts of lactic acid bacteria (LAB) and coliform bacteria, as well as on the microbial activity in the gastrointestinal tract (GIT) as expressed by digesta pH and concentrations of short-chain fatty acids and lactic acid. 2. A total of 450 1-d-old male Ross 308 chickens were randomly distributed to three dietary treatments, with 15 pens per treatment and 10 birds per pen. The dietary treatments consisted of a positive control (PC) supplemented with 60 mg/kg salinomycin, a negative control (NC) without any additives, and the divercin (DIV) supplemented diet containing 0 x 2 mL/kg of the liquid divercin AS7 preparation. 3. The dietary divercin AS7 supplementation significantly increased body weight gain at 35 d compared to the NC group. Moreover, the pH of crop contents was higher and that of caecal contents lower in birds fed on the divercin supplemented diets. 4. Significantly lower counts of LAB were observed in the crops and caeca of the birds treated with divercin. Further, the divercin supplementation decreased lactic and succinic acid concentrations in the crop and ileum. 5. The present study demonstrates that the use of divercin supplemented diets can influence composition and activity of the microbiota in the broiler chicken GIT even in the lower parts that should otherwise not be targeted due to the peptide structure of the bacteriocin.