Challenges of pedodiversity in soil science

Soil diversity is not a completely new concept in soil science. It has been discussed from early times but it was not challenged this much broad. Ibañez with introducing the pedodiversity opened a new conceptual window to ease the induction of the soils complexity, spatial and temporal evolution and distribution. Pedodiversity now attracts more attention and goes to open new windows in soil science. Pedodiversity faces now with different challenges, which could be critical in its way on. Do the current soil diversity indices conceptually define all aspects of soil variability, or do we need to bind them with other characteristics like taxonomic distances? How is the soil individualism defined within the context of spatial variability and soil continuum? How are pedocomplexity, connectance, pedodiversity and soil spatial structure related? Can the changes of soil diversity be accounted as the rate of soil development? Can a range of pedodiversity index be a scale for soil series definition? Initial and some of current pedodiversity studies were/are focused on the concepts and measurement of pedodiversity and soil complexity indices of soilscape compared with the biological diversity and complexity. However, for the pedogenetic studies, the most important issues are the evolutionary concerns out of this approach compared with the other biotic systems. The new contexts, which should be more undertaken in future studies are: functional diversity, temporal diversity, study of soil and landform extinction and preservation. The last question could be: how pedodiversity could be changed under different understanding levels? A case study has been carried out in Charmahal and Bakhtiary province, Iran. Its objectives are the following: comparing the pedodiversity indices combined with and without taxonomic distances within tow replication of a geomorphic surface (Pi 111). What the pedodiversity says here? Did the unique calcification process which rules the soil formation here result in endemism or soil zonality? Do different pedodiversity indices correlate with the soil patterns?     

Scaling hetero-epitaxy from layers to three-dimensional crystals

Quantum structures made from epitaxial semiconductor layers have revolutionized our understanding of low-dimensional systems and are used for ultrafast transistors, semiconductor lasers, and detectors. Strain induced by different lattice parameters and thermal properties offers additional degrees of freedom for tailoring materials, but often at the expense of dislocation generation, wafer bowing, and cracks. We eliminated these drawbacks by fast, low-temperature epitaxial growth of Ge and SiGe crystals onto micrometer-scale tall pillars etched into Si(001) substrates. Faceted crystals were shown to be strain- and defect-free by x-ray diffraction, electron microscopy, and defect etching. They formed space-filling arrays up to tens of micrometers in height by a mechanism of self-limited lateral growth. The mechanism is explained by reduced surface diffusion and flux shielding by nearest-neighbor crystals.     

The prevalence of Yersinia-specific antibodies in cattle in Bavaria

Yersiniosis is considered to be an emerging infection in humans. It is believed that contaminated pork is the main source of infection for man but also beef and cow milk might cause infection in the consumer. Therefore, a survey was carried out to obtain actual data on the prevalence of anti-Yersinia antibodies within cattle. 600 serum samples were taken form 120 farms located in 43 districts of Bavaria, Germany. Antibodies were detected in 396 animals (65.7%) revealing a distribution of 52.3% of anti-YopD, 40.3% of anti-YopM, 24.0% of anti-YopH, 21.2% of anti-YopE and 3.0% of anti-V-antigen antibodies. 21 reactionpatterns out of 32 possible patterns were identified. Anti-YopD and YopM antibodies were sufficient to detect all Yersinia antibody positive sera. No regional differences in the distribution of antibodies were noted.     

Development of a monoclonal blocking ELISA for the detection of antibodies against fowlpox virus

To provide a fast and easy method to detect antibodies against fowlpox virus (FWPV) particularly in high numbers of chicken sera we established a monoclonal blocking enzyme-linked immunosorbent assay (ELISA). We chose two different monoclonal antibodies (mAb), anti-FWPV 3D9/2B3 and anti-FWPV 8F3/2E11, which are both directed against the 39-kDa protein of FWPV strain HP-1. The blocking ELISA depends on the blocking of mAb binding to solid-phase antigen in the presence of positive serum. For an epidemiological study a total of 184 serum samples from Gambian chicken flocks were analysed against each of the mAbs. Four of the sera were shown to contain FWPV antibodies. These four sera showed a positive cut-off value of more than 50% inhibition exclusively in the test against the mAb anti-FWPV 8F3/2E11. This phenomenon can be explained by the binding of the mAbs to distinct epitopes on the same protein.     

Limb Deformities of Farmed Ostrich (Struthio camelus) Chicks in Botswana

Limb deformities were detected in 135 out of 885 ostrich chicks, giving a prevalence of 15.3%. Tibiotarsal rotation affected 73% of the chicks with limb deformities, whereas rolled toes accounted for 36%. The right leg was more often affected than the left leg. The incidence of limb deformities was highest in 2- to 3-week-old ostrich chicks. The incidence of limb deformities was highest at the beginning of the breeding season and lowest towards the end, when it was relatively warmer. The mean serum manganese and zinc levels in deformed ostrich chicks were higher than the levels reported for normal chicks.     

Coccidia oocysts in the faeces of farmed ostrich (Struthio camelus) chicks in Botswana

Coccidia oocysts were demonstrated in the faeces of 53 (about 34%) of 156 apparently healthy ostrich chicks. Young chicks had the highest proportion of infestation while those more than 9 weeks old had no oocysts at all in their faeces. These coccidia may be considered no pathogenic since the infected chicks grew normally without any evidence of diarrhoea.     

Culicoides (Diptera: Ceratopogonidae) associated with horses at Mogoditshane,Gaborone, Botswana

Veterinary Research Communications -     

Spatial modelling indicates Striga seedbank density dependence on rainfall and soil traits in the savannas of northern Nigeria

Striga is one of most notorious weeds devastating crop production in the dry savannas of northern Nigeria. The weed attacks most cultivated cereals and legumes with crop losses as high as 100% when no control measure is employed. Studies conducted in the dry savannas of Nigeria indicated that Striga seedbank is strongly related to soil and climate properties. This study was conducted to model Striga hermonthica seedbank zones in the dry savannas of Nigeria based on soil and climate properties of the areas. Using multi-stage spatial sampling, 169 soil samples were collected at the centroids of 25 × 25 km grids across the study area and analysed for physico-chemical properties. The number of Striga seeds were counted from the soil samples using water elutriator and potassium bicarbonate method. Daily temperature, relative humidity and rainfall for each point were downloaded from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). Minimum and maximum temperatures, and relative humidity were accessed from National Aeronautics and Space Administration (NASA POWER). Thresholds of various soil and climate variables for optimum concentration of Striga seedbank were analysed using boundary line analysis (BLA). From the BLA, optimum amount of rainfall for high Striga seedbank was 549 mm per annum. While temperature has a wide suitability range for Striga seedbank development. Principal component analysis was used to reduce dimensionality of the dataset into principal components (PCs). Seven PCs which explained 75.6% variation in the data were retained and used in the weighed overlay modelling (WOM). The weighted overlay map produced five distinct Striga seedbank zones; very low, low, moderate, high and very high. More than 60% of the study area had moderate to high Striga seedbanks. The zones vary mostly based on soil, climate and Striga seed count. The establishment of the optimum levels of the environmental factors at which Striga seedbank is favoured will assist in designing a more site-specific Striga management. However, for scalability purpose, adoption of the Striga zoning approach can be useful.     

Mycorrhizal protection of chili plants challenged by <Emphasis Type="Italic">Phytophthora capsici</Emphasis>

Hydrogen peroxide (H₂O₂) has been implicated in many stress conditions. Control of H₂O₂ levels is complex and dissection of mechanisms generating and relieving H₂O₂ stress is difficult, particularly in intact plants. Here the role of the mycorrhizal inoculation in chili plants challenged with Phytophthora capsici was investigated to study the effect on hypersensitive response. In the treatment without mycorrhiza (treatment T3) and with mycorrhiza (considered treatment T4) visible disorders were detected two days after inoculation with P. capsici, but in the next days T3 plants rapidly developed 25% more necrotic lesions on the leaves than T4 plants. Leaf necrosis correlated with H₂O₂ accumulation and the greater damage observed in T3 plants coincided with larger accumulation of H₂O₂ after 12 h of inoculation accompanied with an increase in POX (peroxidase) and SOD (superoxide dismutase) activity. T4-infected and mycorrhizal plants exhibited an earlier accumulation of H₂O₂ starting 6 h after inoculation with lower levels compared to T3 plants. Correlated with observed damage, POX and SOD activity measured in T4 plants indirectly suggest a smaller accumulation of ROS (reactive oxygen species) leading to a decrease in the wounds observed and slightly diminishing the advance of the pathogen. According to these findings, we conclude that mycorrhizal colonization contributes significantly in maintaining the redox balance during oxidative stress, but the exact mechanism is still uncertain.