Iron oxides as weathering indicator and the origin of Luvisols from the Vistula glaciation region in Poland

Purpose

The aim of the research was to determine the effect of lithogenic and pedogenic processes on the formation of Luvisols from the area of Vistula glaciation on the base of profile distribution of iron oxides and total iron in relation to texture and physicochemical properties. The indices of weathering of the soil material in genetic horizons were calculated, and changes in the content and forms of iron oxides were evaluated.

Materials and methods

The predominant type of soil in the study area is Luvisols under agricultural use, formed from silt formations on loam. The analyses were made applying the following methods: grain size composition using the sieve method and hydrometer method, the interpretation of the results was performed according to the World Reference Base for Soil Resources classification, the pH of soils was measured with the potentiometric method, C-organic with the Walkley-Black dichromate method, the content of the following iron forms was determined (total iron (Fe_t) after the mineralization of soils in the mixture of HF and HClO₄ acids), free iron oxides were extracted using dithionite-citrate-bicarbonate method, and amorphous iron oxides after the ammonium oxalate extraction (using the Philips 9100PU apparatus). The clay mineralogy was estimated by X-ray diffraction analysis.

Results and discussion

It was observed that total iron enrichment occurs in argic horizons accompanied by iron depletion in luvic horizons, while the profile distribution of iron is similar to the distribution of clay. The (Fe_d/Fe_t) ratio indicates a low degree of weathering; the highest values were observed in argic (Bt) horizons, which confirms the effect of the process of pedogenesis on the value of that index. In the soils investigated, crystalline iron oxides generally dominate over the amorphous forms. The mineralogical composition of clay fraction separated from the upper part of soils was different as compared to the underlying material.

Conclusions

The results of the study showed that iron contents (together with the other indicators) and its forms can be used to distinguish soil layers of different origin. The depth distribution of Fe_d, Fe_o and Fe_t within soil profiles indicates that the soil material may be of different lithogenic origin in the studied pedons.

     

Tetraploid bahiagrass hybrids: breeding technique,genetic variability and proportion of heterotic hybrids

Manipulating apomixis for fixing tetraploid bahiagrass (Paspalum notatum Flüggé) hybrids exhibiting superior agronomic characteristics would be a valuable tool for the genetic improvement of this species. The objectives were to create a second generation of hybrids by crossing sexual first-generation tetraploid hybrids (FGTH) and unrelated apomictic FGTH or ecotypes, determine the segregation for mode of reproduction, and estimate the resulting genetic variation and heterosis for several agronomic characteristics. The segregation for mode of reproduction was analyzed using mature embryo sac observations. Field measurements and visual ratings were used to evaluate the growth habit, production of inflorescences, cool-season growth and freeze resistance of hybrids. A ratio of 4.6:1 between sexual and apomictic hybrids was observed. Only 3% of the progeny was classified as highly apomictic. The low proportion of highly apomictic progeny restricts the feasibility of this breeding approach. Large genetic variation was observed among hybrids for growth habit, cool-season growth and freeze resistance. The proportion of hybrids exhibiting heterosis was high for plant height, cool-season growth, and freeze resistance. The tetraploid bahiagrass germplasm contains a large diversity for traits of agronomic importance that can be exploited for the genetic improvement of this species.     

The introduction of modern forest management and clear-cutting in Sweden: Ridö State Forest 1832–2014

The effects of clear-cutting and potential alternatives continue to be hot topics during discussions of forestry and nature conservation. This study presents forest data from Ridön, an island in Lake Mälaren in central Sweden, where forest management and clear-cutting have been applied for almost 200 years. The main objective of the study was to identify changes in forest management and forest conditions over time. The forest transition in Sweden during the 1800s is also covered, and the importance of early forest experiments is discussed, exemplified by Ridön. This study is based on eight forest management plans and maps, from 1832 to 2014. Our results show a transformation from large, continuous areas of heterogeneous forest to small homogeneous stands. Clear-cutting has been the main logging method applied to Ridön for almost 200 years, which is in contrast with the general historical trend of selective cutting preceding clear-cutting in the Nordic countries. Our analysis shows that forestry has changed from the exploitation of resources to sustainable management. Currently, forest management at Ridön aims to create a nature reserve characterized by uneven-aged forest with an increased deciduous component. Hence, the intention is to obtain a forest similar to as it was in 1832. By analyzing spatially precise data on forest stands over long periods and in relation to contemporary silvicultural methods, it is possible to discern the impact of forest management, to understand the drivers of the long-term changes in managed forest, and it also allows for a more educated discussion on today’s forest management.     

When is it biological control? A framework of definitions,mechanisms, and classifications

Journal of Pest Science - Biological control, or biocontrol, is the exploitation of living agents (incl. viruses) to combat pestilential organisms (incl. pathogens, pests, and weeds) for diverse...     

Correction to: When is it biological control? A framework of definitions,mechanisms, and classifications

Journal of Pest Science - A correction to this paper has been published: https://doi.org/10.1007/s10340-021-01386-z     

First report of Calonectria montana causing damping‐off disease on pine and spruce seedlings in Europe

In 2015–2016, damping‐off symptoms were observed on Pinus sylvestris and Picea abies seedlings in four forest nurseries in Poland. Some Calonectria isolates were obtained from symptomatic seedlings by culturing pieces of necrotic tissue on malt extract agar.Morphological and molecular analyses revealed that isolates represent Calonectria montana, a recently described species from natural forests in China. The isolates represent the first detection of this species outside of Asia. Pathogenicity tests demonstrated that C. montana is a severe pathogen of P. sylvestris seedlings.     

Effect of Temperature and Screw Speed on Stability of Fumonisin B1 in Extrusion-Cooked Corn Grits

Corn grits spiked with fumonisin B₁ (FB₁) at a level of 5 μg/g were extrusion cooked in a corotating twin-screw extruder at different temperatures (140, 160, 180, and 200°C) and screw speeds (40, 80, 120, and 160 rpm). Good recoveries of FB₁ were obtained from the nonextruded as well as the extruded grits by using high-performance liquid chromatography. Both the barrel temperature and the screw speed significantly (P ≤ 0.05) affected the extent of fumonisin reduction in extruded grits. As expected, the FB₁ recovered decreased with an increase in temperature and a decrease in screw speed. The amount of FB₁ lost from cooking grits at the different extrusion parameters used in this study ranged from 34 to 95%. About 46–76% of the spiked FB₁ was lost when the grits were cooked at temperatures and screw speeds that resulted in acceptable product expansion and color.     

Multiple myelomas in cats

Multiple myelomas are uncommon neoplasms of the bone marrow of cats [Weber NA, Tebeau CS (1998) An unusual presentation of multiple myeloma in two cats. Journal of the American Animal Hospital Association34 (6), 477-483]. Nine cats diagnosed with multiple myelomas were retrospectively identified over a 16-year period (1986-2002). Cats with multiple myelomas were older than 7 years (mean age 11.7 years); six males and three females were affected (2.1), but no breed predisposition was evident. Treatment of multiple myelomas consisted of supportive management in the nine cats and anti-neoplastic therapy in eight cats. Supportive treatment consisted of maintaining hydration, renal function and antimicrobial therapy even when there was no sign of infection. Anti-neoplastic therapy with melphalan and prednisolone was carried out in eight cats. Three failed to respond to treatment and five responded to treatment, but the response was only partial and temporary in one cat. The five cats that responded were improved clinically and had reduced serum protein levels. Five out of eight cats (63%) responded to chemotherapy, and it appeared to be complete in four cats and partial in one cat. Survival time in those cats was 15, 4, 17 and 24 months.     

Transvenous electrical cardioversion of equine atrial fibrillation: technical considerations

Conventional treatment of equine atrial fibrillation (AF) involves administration of quinidine salts. Most uncomplicated cases respond to treatment, but pharmacologic cardioversion involves a range of adverse effects, and some horses are unable to tolerate medication. A study was undertaken to develop transvenous electrical cardioversion (TVEC) as an alternative treatment. Safety issues and catheter placement techniques with catheter-integrated cardioversion electrodes were investigated, and responses to shock application were evaluated. After the premortem catheterization of elective-euthanasia horses, no tissue abnormalities were detected at postmortem examination. To evaluate the response to the application of shocks and appropriate electrode positions, an electrical cardioversion of research horses in chronic AF was then attempted. After catheterization of the right atrium (RA) and pulmonary artery through the right jugular vein, horses were placed under general anesthesia. Biphasic, truncated exponential shock waves were delivered at incremental energies until cardioversion was achieved or until a maximum energy of 300 J was reached. Five treatment events were applied to 3 horses, with cardioversion achieved in one of the treatment events. No adverse effects of cardioversion attempts or general anesthesia were observed. The procedure was then applied to 8 client-owned horses, with cardioversion achieved in 7. No adverse responses to appropriately delivered shocks were observed. No antiarrhythmic medications were administered to any horse at any stage. Catheter design and placement technique evolved throughout the study, with combined ultrasonography and pressure guidance proving most effective in achieving appropriate electrode placement. Results suggest TVEC, as applied in the present study, is a safe, effective, and realistic therapeutic option for equine AF.