Soil Organic Carbon,Total Nitrogen,and Soil pH,in a Long-Term Continuous Winter Wheat (Triticum Aestivum L.) Experiment

Continuous use of organic and inorganic fertilizers influences soil physical and chemical properties. Stored samples from the last 24 years of the Magruder Plots were analyzed to document changes in soil organic carbon (SOC), total nitrogen (TN) and soil pH. Since 1947, the same six treatments have been evaluated. Treatments included the use of cattle manure, inorganic nitrogen (N), phosphorus (P), potassium (K), and lime (L). Each year, a composite surface soil sample (0–15 cm) was taken in each plot, air-dried at ambient temperature, ground to pass a 2 mm sieve, and stored at room temperature, 25°C. Averaged over 24 years’ the manure plots resulted in the highest SOC and TN. Manure application maintained SOC at 0.92 and adequate soil pH (>6.0). The use of commercial fertilizers lowered soil pH over time but had higher yields compared to the manure plot.     

Evaluation of different extenders for the cold storage of meagre (Argyrosomus regius) semen

Meagre (Argyrosomus regius) is considered a potential candidate for aquaculture diversification in southern Europe. The main objective of this experiment was to develop a cold storage protocol for meagre semen to facilitate artificial reproduction techniques. Three extenders (non‐activating medium, 0.9% NaCl, and 0.9% NaCl with glycine and glucose) in three different sperm:extender dilutions (1:4, 1:9 and 1:19) were tested in a full factorial design. The quality parameters assessed along the storage time were the sperm motility, viable sperm percentage, adenosine triphosphate (ATP) content, and bacterial growth. The 0.9% NaCl and 0.9% NaCl with glycine and glucose extenders and the 1:4 and 1:9 dilutions maintained a higher sperm motility and a higher sperm linearity for a longer period time. Sperm viability was maintained at a higher value over a longer period with the 0.9% NaCl and 0.9% NaCl with glycine and glucose extenders. Sperm motility and viability appeared to be the main parameters showing the loss of semen quality during cold storage. Meagre semen demonstrated an ability to be stored for up to 10 days at 4°C when using 0.9% NaCl in a 1:4 dilution. These results contribute to a better understanding of the causes of fish semen quality deterioration during cold storage.     

Potential of Tamarix africana and other halophyte species for phytostabilisation of contaminated salt marsh soils

Purpose

Salt marsh plants are colonising wastes from a steel plant deposited on the Coina River Banks posing a potential contamination risk to the Tagus estuary ecosystem. The objectives of this study were to assess the uptake, accumulation and translocation of hazardous elements/nutrients in three spontaneous halophytic species, to evaluate the capacity of Tamarix africana to stabilise a contaminated salt marsh soil, and to evaluate the ecotoxicity of the pore water and elutriates from phytostabilised soils.

Materials and methods

The work comprises the following: fieldwork collection of soil samples from Coina River (an affluent of Tagus River) bank landfill, estuarine water and spontaneous plants (Aster tripolium, Halimione portulacoides and Sarcocornia sp.), and greenhouse studies (microcosm assay) with T. africana growing in one landfill salt marsh soil, for 97 days, and watered with estuarine water. Soils were analysed for pH, EC, C_organic, NPK, iron and manganese oxides. Soils total (acid digestion) elemental concentrations were determined by ICP/INAA. Estuarine waters, plants roots and shoots (acid digestion), soils available fraction (diluted organic acids extraction-RHIZO or pore water), and salts collected from the T. africana leaves surface were analysed for metals/metalloids (ICP-MS). Ecotoxicity assays were performed in T. africana soil elutriates and pore waters using Artemia franciscana and Brachionus plicatillis.

Results and discussion

Soils were contaminated, containing high total concentrations of arsenic, cadmium, chromium, copper, lead and zinc. However, their concentrations in the available fraction were <4 % of the total. The estuarine waters were contaminated with cadmium, but negligible ecotoxicological effect was observed. The spontaneous plants had significant uptake of the above elements, being mostly stored in the roots. Elemental concentrations in the shoots were within the normal range for plants. These species are not hazardous elements accumulators. Tamarix africana was well adapted to the contaminated saline soils, stored the contaminants in the roots, and had small concentrations of hazardous elements in the shoots. Excretion of hazardous elements by the salt glands was also observed. Elutriates from soils with and without plant did not show ecotoxicity.

Conclusions

The salt marsh species play an important role in the stabilisation of the soils in natural conditions. Tamarix africana showed potential for phytostabilisation of saline-contaminated soils. The low translocation of the elements from roots to shoots and/or active excretion of the elements by the salt glands was a tolerance mechanism in T. africana.

     

Response of fungal and plant communities to management-induced overstorey changes in montane forests of the Western Carpathians

The effect of forest management on biodiversity is a crucial issue for sustainable forestry and nature conservation. However, the ways in which management affects macrofungal and plant communities and diversity of mountain temperate forests still remain poorly understood. We performed a random sampling stratified by stand age and stand type on the sites of temperate montane fir–beech forests. Diversity of macrofungi and the vascular plant understorey in beech- and spruce-dominated managed stands was investigated and compared to primeval forests located in the Po?ana Biosphere Reserve, Western Carpathians. Both the vascular plant and the macrofungal communities were altered by management, and the response of the macrofungal species (especially wood-inhabiting fungi) was more pronounced in terms of species composition change. Species turnover evaluation seems to be an important tool of forest natural status assessment, because alpha diversity did not change as much as species composition. Certain species of Carpathian primeval forests were confirmed as good indicators for natural forest change; others were proposed. Species pool and mean number of species per plot were the highest in unmanaged fir–beech forests, and species diversity significantly decreased in spruce plantations. The number of species decreased significantly due to the change of canopy tree species composition only in the macrofungal communities. As an outcome for forest management, we recommend keeping mixed forests involving all natural tree species and providing at least a minimal amount of dead wood necessary for wood-inhabiting organisms and leaving some area of unmanaged natural forests within complexes of managed stands.     

Quantitative and qualitative characterisation of humic products with spectral parameters

Purpose

The application of different humic products for the treatment of soils and plants has increased in recent years. The characteristics of humic products, such as the content and composition of organic carbon and the maturity, provide valuable information which is essential for an adequate application. Such information is crucial for manufacturers, business consultants and users involved in the production, distribution and implementation of humic products. This article presents the correlation between the quantitative indicators of commercial humic products and their spectral characteristics via measurements in the ultraviolet spectrum at 300 nm, in the visible area at 445 and 665 nm and in the near-infrared spectrum at 850 nm.

Materials and methods

We evaluated humic products (liquid and solid) of different origins. Via wet combustion, the content of total organic carbon in humic products can be determined. The precipitation of humic acids from the starting solution determines the composition of the humic products in terms of humic acids (HAs) and fulvic acids (FAs). The dissolution of HAs determines their concentration by titration, while the specific extinction can be assessed via spectrophotometry via measuring the absorption of HAs spectra at the following wavelengths: 300, 465, 665 and 850 nm. The degree of aromaticity and condensation of humic products determines the optical density of the HAs via the E₄/E₆ ratio.

Results and discussion

The content of total organic carbon varied widely from 0.55 to 37.5% across all groups. The content of carbon in HAs, as a percentage of the total carbon in fulvic-type humic products, ranged from 1.29 to 16.00%, while in humic-type products, it ranged from 51.43 to 91.92%. The minimum value of the E₄/E₆ ratio was 2.97, while the maximum value was 6.35. We observed a direct relationship between the dominant type of acids in humic products and the E₄/E₆ ratio.

Conclusions

The optical density of HAs indicates their quality characteristics. The presented optical characteristics for humic products show that there is a direct relationship, especially between HAs/FAs and E₄/E₆ ratios. Measurement at 300 nm (E₃₀₀) in the near-ultraviolet area and at 850 nm (E₈₅₀) in the near-infrared area can increase the range of the spectral study.

     

Pulp and Paper Mill Effluent Treated by Combining Coagulation-Flocculation-Sedimentation and Fenton Processes

Pulp and paper industries face serious environmental challenges, especially with regard to the conservation of water resources. Chemical thermal mechanical pulping (CTMP) is a process of pulping that combines chemical and mechanical pulping. This reduces the volume of water used in the process. But on the other hand, CTMP generates an effluent with high concentration of organic matter and is difficult to treat. This study evaluated the efficiency in the combination of physicochemical pretreatment by coagulation-flocculation-sedimentation (CFS) process and advanced oxidation process (AOP) by Fenton in sequence to treat CTMP effluent of a Brazilian industry. At first, the best treatment conditions for this type of effluent were determined. To evaluate the efficiency, pH, chemical oxygen demand, biochemical oxygen demand, total organic carbon, lignin contents, color, total phenolic contents, turbidity, and solids were measured before and after treatment. The acute toxicity on Daphnia magna was also determined. The treatment with CFS showed better results in the removal of solids and Fenton in the removal of recalcitrant compounds, such as lignin, demonstrating the need to use them in sequence. Combining CFS and Fenton to treat CTMP effluent allowed to achieve a removal efficiency of 95% for TOC, 61% for COD, and 76% for lignin contents.     

Lethal and sublethal responses of <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> populations to essential oils

The present study aimed to assess the lethal and sublethal responses of five populations of S. zeamais to the essential oils of Ocimum basilicum and Piper hispidinervum, through toxicity, locomotor behavior (flight and walking activities) and physiological (respiration rate and body mass) evaluations. The populations of S. zeamais were obtained from Machado—MG, Paracatu—MG, Piracicaba—SP, Recife—PE and Tunápolis—SC. To estimate the LC₅₀ of each oil for each population, fumigation tests were performed. The population from Recife exhibited the lowest instantaneous rate of increase (ri) as well the lowest consumption of grain mass. However, Piracicaba was considered the susceptibility pattern, presenting the lowest LC₅₀ for both essential oils, no statistical difference was observed among populations or treatments in the flight activity bioassays. The essential oils effect on walking activity and respiration rates varied among populations. The population from Recife presented the highest walked distance and walk speed, with the lowest resting time and number of stops, as well as the lowest respiration rate and body mass. The present study highlights the importance of the study on population responses, as the five populations of S. zeamais exhibited different patterns of toxic and behavioral effects when subjected to the essential oils of P. hispidinervum and O. basilicum.     

Do fish isotopic niches change in an Amazon floodplain lake over the hydrological regime?

Floodplain lakes are ecosystems characterised by annual flood and dry cycles. Fish ecology is influenced by the flood pulse due to the large influx of allochthonous food resources and diversification of habitats during the flood cycle, while during the dry cycle, fishes tend to be confined in reduced habitat. The aim of this study was to evaluate the seasonal variation in trophic niche width and overlap of four species—Mylossoma duriventre, Prochilodus nigricans, Cichla.pleiozona and Serrasalmus rhombeus—in an Amazonian floodplain lake. Stable isotope analyses were used to estimate trophic niche width and overlap during the flood and dry seasons. We hypothesised broader niche width for all species during the flood cycle and a higher degree of overlap between the two piscivorous fishes during the dry cycle. Isotopic niche width was 72% broader for P. nigricans, 61% for S. rhombeus and 54% for C. pleiozona during the dry cycle, which did not support our hypothesis. Core niche width overlaps were not observed between piscivorous species in either flood or dry cycle. The results indicate that seasonal variation in isotopic niche width is specific to feeding habit. Understanding how fish trophic ecology responds to changes in the hydrological regime during the seasons is crucial for sustainable fishery management in a region where many people rely heavily on fish for nutritional and economic purposes.