Search Results (1,391)

The complex polysaccharide pullulan is characterized as a glucose-containing biopolymer that is both water-soluble and neutral in polarity. A variety of commercial applications exist for pullulan, including its utilization as a flocculant, a blood plasma substitute, a food additive, a dielectric material, an adhesive, or a packaging film. The fungus Aureobasidium pullulans has used several hydrolysates derived from plant biomass or starch-containing processing coproducts to support polysaccharide production. These include various plant biomass or processing coproduct streams such as lignocellulosic-containing peat, prairie grass, stalks, hulls, straw, shells, and pods or starch-containing coproducts from the processing of corn, rice, jackfruit seeds, palm kernels, cassava, and potatoes. The pullulan concentration produced by A. pullulans and the pullulan content of the polysaccharide depend on the plant hydrolysate carbon content and the strain used. If a lower-cost culture medium for fungal pullulan production were to be developed, a more economical approach to synthesizing commercial pullulan would be the utilization of plant-derived hydrolysates. This review examines the ability of selected hydrolysates of lignocellulosic plant biomass or plant-derived starch-containing processing coproducts to support A. pullulans polysaccharide synthesis in order to identify those substrates with the greatest potential for reducing the cost of commercial pullulan. Full article

Microgreens are promising crops for low-input systems, but the roles of species traits and root environments under uncontrolled greenhouse conditions are not yet fully addressed. In this study, mibuna and pak choi were evaluated in the presence or absence of substrate to clarify how genetic and physical factors shape growth and biochemical composition. Clear species-dependent differences emerged. Pak choi showed higher constitutive levels of chlorophyll a, anthocyanins, and key osmotic ions, and these features contributed to a more hydrated tissue profile. Mibuna instead exhibited a higher dry matter content, approximately 7% compared with 5.86% in pak choi, and a lighter canopy. The use of peat markedly improved overall growth. Fresh yield increased by more than 50%, and dry yield increased by almost 48% compared with the substrate-free system. Peat also enhanced organic acid metabolism, with malate and citrate increasing by 277 and 102%, respectively. Despite such differences, nitrate concentrations remained low and within safe limits for leafy vegetables in all treatments. The results indicate that species identity and the cultivation system significantly shaped overall microgreen performance under low-input conditions. Understanding these drivers provides a foundation for optimizing production while maintaining desirable nutritional traits. Full article

The exploration of Doggerland, the prehistoric landscape that once connected Britain to the continent, remains one of Europe’s most significant archeological challenges. This paper presents a study into the palaeolandscape and the paleoenvironmental development of Doggerland, through the geochemical analyses of a core (ELF019) taken from the southern North Sea. The thermal properties divided the core into three sedimentary zones based on the variations in organic matter and carbonate content. Organic biomarkers were used to distinguish between terrestrial and aquatic vegetation inputs, revealing alternating freshwater, terrestrial, and marine input influences. Chemostratigraphy defined six depositional zones that corresponded with the identified thermal and biomarker data. Radiocarbon dating of peat-derived humic fractions anchored the key environmental transition between freshwater and saline deposition to the Greenlandian period of the Lower Holocene (10,243–10,199 Cal BP). The integrated geochemical evidence suggests a transformation from freshwater silts, low organic content, and sandy clay deposit to saline clay marine deposit. The progressive transformation may reflect the inundation sequence that led to the final submergence of Doggerland. Full article

Amid global freshwater scarcity and soil salinization, brackish irrigation is a potential alternative, yet its effects under low-leaching soilless systems remain unclear. We tested brackish irrigation (30 mmol L⁻¹ NaCl; EC ≈ 4.8 dS m⁻¹, including fertilizer) on lettuce (Lactuca sativa L.) grown in peat–perlite substrates with non-saline (CK), mildly saline (M), and moderately–severely saline (S) initial salinity. Substrate moisture and bulk electrical conductivity (EC_b) were monitored at upper, middle, and deep layers with multi-depth sensors; lettuce physiological and growth traits were measured. Under negligible drainage, salt moved downward promptly after irrigation in CK, accumulated at the surface in M, and remained high with spatiotemporal variability in S. Brackish irrigation had minimal effects on biomass and water use efficiency in CK and M, but significantly reduced both in S. These findings support tailoring brackish irrigation to initial salinity severity and motivate future work to measure drainage and calibrate EC indices to establish operational thresholds. Full article

The demand for ready-to-eat salads made from leafy vegetables such as wild rocket (Diplotaxis tenuifolia L.) continues to increase, driven by consumer preference for convenience foods with high levels of bioactive compounds. However, reducing the environmental impact of wild rocket production requires both organically enriched growing substrates and sustainable alternatives to conventional plastic packaging. This study assessed the effects of three cultivation substrates and three biodegradable packaging materials (polylactic acid (PL), cellulose kraft (CK), and kraft-reinforced polylactic acid (PLK)) on the postharvest performance of wild rocket stored at 4 °C for 7 and 14 days. Plants were grown in coco peat (CP), coco peat supplemented with livestock compost (90:10; CP+LC), and coco peat mixed with mushroom compost (50:50; CP+MC). Yield and key pre- and postharvest quality attributes, including nitrate accumulation, phenolic content, antioxidant capacity, colour, and weight loss, were evaluated. The CP+LC substrate resulted in the highest harvest yield, whereas CP promoted higher phenolic content and antioxidant capacity. Among the packaging materials, PLK provided the most balanced internal atmosphere, effectively reducing dehydration and condensation while preserving superior sensory quality after 14 days of storage. Overall, the combination of organic compost amendments, particularly CP+LC, with PLK bio-based packaging represents a promising and sustainable strategy for maintaining postharvest quality and reduce the environmental footprint of minimally processed wild rocket within short food supply chains. Full article

This research investigates ten sediment cores extracted from Holocene deposits in Labu, northern Temburong District, Brunei Darussalam, to provide an initial inventory of the encountered peat-forming environments. Proximate, ultimate, and geochemical analyses were performed, along with mineralogical characterisations and ¹⁴C radiocarbon dating, as well as preliminary palaeontological and palynological examinations of the peat and underlying substrate layers. Localised organic deposits, termed “peat pockets”, were identified, with the oldest found to have begun accumulating under topogenous-mire conditions during the Middle Holocene. This coincides with the Mid-Holocene sea-level rise, which is thought to have peaked at 6000–4500 years BP. However, our data suggest that sea level may have continued rising until approximately 2500 years BP, peaking between 2500 and 1700 years BP, followed by delta progradation in Temburong. These “peat pockets” gradually coalesced into larger topogenous mires associated with estuarine environments. Over time, they became less influenced by marine conditions and increasingly shaped by a freshwater regime, resembling an upper delta system, similar to the present-day landscape observed in Temburong. It is proposed that these mires transitioned from a topogenous to an ombrogenous phase approximately 250 to 320 years BP, as inferred through forward age extrapolation based on a constant accumulation rate. The findings support the hypothesis of inland coastline migration during the Middle Holocene, followed by retraction due to deltaic progradation in the Late Holocene. These fluctuations align with well-established sea-level changes driven by climatic variability. Full article

The use of manure as a growing medium for horticultural crop cultivation is a sustainable practice that may allow a reduction in the production costs and the environmental burden of bulky waste management. For this purpose, the current study investigated the partial substitution of peat with manure at various rates (0% (GS1), 100% (GS2), 80% (GS3), 60% (GS4), 40% (GS5), and 20% (GS6)) in pot-cultivated purslane. Our results indicate that the substitution of peat with manure may increase crop yield by 60% to 80%. Moreover, the nutritional value was improved for specific manure rates; for example, the ash and carbohydrate contents in leaves increased at 60% and 20%, respectively, while the fat and carbohydrate contents in shoots increased at 80% and 20%, respectively. P content increased in both leaves and shoots when manure was added to the growing medium, while application at low rates (e.g., 20%) resulted in decreased N and K content. Finally, regarding leaf total phenol and flavonoid contents, as well as antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, values increased when manure was added at 40% to 60%; in shoots, increased values were observed for these parameters when manure was applied at 0% or 100%. In conclusion, our results suggest that peat substitution with manure is a viable, sustainable practice in purslane cultivation in pots without compromising the yield and quality parameters of plants. However, more species and different types of manure must be tested to design tailor-made growing media for horticultural crops. Full article

Intensive agriculture, ecosystem degradation, and declining soil quality highlight the urgent need for sustainable land use strategies. The cultivation of short-rotation woody crops (SRC), combined with fertilization using sewage sludge digestate (SSD), offers a promising approach to recycle nutrient-rich waste and promote soil organic carbon (SOC) accumulation. This study evaluated SOC concentrations, stocks and their spatial distribution in the 0–20 cm soil layer under SRC cultivation, with and without SSD fertilization, across contrasting soil types in Eastern Lithuania. The investigated soils included mineral (Luvisols (LV), Retisols (RT), Planosols (PL), Arenosols (AR)), organo-mineral (Gleysols (GL)), and organic soils (Histosols (HS)), representing textures from sand to peat and classified according to the World Reference Base for Soil Resources (WRB). Part I assessed baseline SOC variability in unproductive areas planted with hybrid poplars (Populus spp.) and hybrid aspen (Populus tremula × P. tremuloides) up to 20 years old. Part II examined SOC changes in three SRC fields of different ages (3–10 years), including unfertilized and SSD-fertilized stands. SOC concentrations increased consistently from mineral (1.14–1.80%) to organo-mineral (2.13–3.20%) and organic soils (6.37–17.53%). Heavier-textured soils accumulated more SOC than lighter soils, showing a strong positive correlation between SOC and soil texture (r = 0.82, p ≤ 0.01). SRC cultivation increased SOC across all soil types, while SSD fertilization further enhanced accumulation, with fertilized fields showing SOC increases of 0.50–1.07 percentage points and carbon stocks by 18.8–41.7 t ha⁻¹, compared with smaller increases in unfertilized fields. Spatial visualization of SOC further highlighted long-term accumulation patterns across soil types, confirming the trends observed under SRC cultivation and SSD fertilization. Full article

Horticultural reliance on non-renewable peat faces critical sustainability challenges. Low-temperature biochar (LTB) presents a promising alternative, offering higher biochar yields and lower energy inputs compared to conventional high-temperature biochar. However, LTB’s distinct physicochemical properties necessitate empirical validation of its efficacy as a peat substitute. This study investigated rice straw-derived LTB (pyrolyzed at 350 °C for 10 or 30 min) as a peat substitute at different ratios (10%, 20%, 40%), combined with three Hoagland nutrient solution concentrations (25%, 50%, 100%), on the growth, substrate properties, and fruit quality of dwarf tomato. The results show that a 10–20% LTB substitution improved substrate physical properties (reduced bulk density, increased porosity) and promoted plant growth (biomass, height). Conversely, a 40% LTB substitution inhibited growth, primarily attributed to osmotic stress caused by excessively high substrate electrical conductivity (EC). At the optimal 10–20% rates, tomato yield and fruit quality (soluble solids, lycopene, vitamin C) were significantly enhanced. Most importantly, a comprehensive evaluation revealed that 10–20% LTB substitution allowed for a 50% reduction in nutrient solution concentration while achieving a comprehensive performance comparable to the full-strength nutrient control. This study indicates that LTB could effectively replace a portion of peat, potentially enhancing dwarf tomato yield and quality while reducing chemical fertilizer dependency by up to 50%. These findings point toward a possible pathway for more resource-efficient horticultural practices. Full article

The sustainable management of organic residues remains a major challenge in agriculture. Vermicomposting offers an environmentally friendly strategy to convert organic waste into nutrient-rich, biologically stable biofertilizers. This exploratory study evaluated the effects of vermicompost and its leachate, produced from sewage sludge and vineyard pruning residues, on cucumber (Cucumis sativus L.) germination and 25-day early seedling growth. Treatments included a control (peat and perlite, CNT), two vermicompost doses, 20 g kg⁻¹ and 40 g kg⁻¹ (VC_D1 and VC_D2, respectively) and a 5% (v/v) vermicompost leachate (VC_L) applied as the sole irrigation source. Foliar nutrient contents and physicochemical properties of the substrate and leachate were determined. Germination was not significantly affected (p > 0.05), but VC_D1 promoted slightly faster and more uniform seed emergence. Growth responses were dose dependent, with VC_D1 significantly enhancing shoot biomass (approximately 15% than the CNT and VC_D2) and providing a balanced foliar nutrient profile, whereas VC_D2 significantly reduced growth, promoted excessive foliar K and P, and lower Ca, Fe, and Mn contents. VC_L enhanced foliar N accumulation but did not significantly (p > 0.05) increase biomass. Both vermicompost and its leachate were pathogen-free, with metal concentrations below regulatory limits. Overall, these findings suggest that, under the tested conditions, vermicomposting these residues can generate potentially safe amendments for cucumber seedling growth, though dose optimization is essential. This exploratory approach supports residue valorization and contributes to circular economy principles and sustainable agriculture goals. Full article

In achieving sustainable development goals, soils play a key role in environmental protection, natural resources, and food security. Peatlands are particularly important here, as they function at the interface between terrestrial and aquatic ecosystems and store large amounts of organic matter. However, organic soils are highly susceptible to transformation and degradation; therefore, their degradation caused by, among others, drainage properties is a high risk to both the environment and agriculture—it disrupts the ecosystems, causes greenhouse gas emissions, and eutrophicates the hydrosphere. Soil degradation in drained peatlands is associated with the transformation of soil organic matter (SOM), which in organic soils is the dominant component of the solid phase of the soil. The aim of our study was to assess the properties and degree of organic matter transformation in drained temperate peatland soils, with particular emphasis on sequential fractionation of SOM and humic acid properties. Due to the fact that in Poland, as many as 90% of non-forest peat bogs have been drained, we compare the mursh horizons that formed after peat bog drainage with the peat horizons that constitute the parent rock (where anaerobiosis occurs and morphological changes in the soil material are absent due to peat bog drainage). Studies were conducted on 11 soil profiles located in central-eastern Poland. Basic physicochemical soil properties were determined: pH, bulk density, contents of ash, SOM, total carbon (TC), and total nitrogen (TN). Sequential carbon fractionation was used to qualitatively analyze organic matter, which allowed for the identification of labile fractions, lipid fractions, humic substances (fulvic and humic acids), and residual fractions. Humic acids (HAs) were extracted using the Schnitzer method and analyzed for their elemental composition and spectrometric parameters in the VIS range. It was demonstrated that SOM transformation in drained temperate peatland soils was correlated with comprehensive changes in the soil’s physical and chemical properties. Compared to peat horizons, topsoil horizons were characterized by higher ash content and density, lower SOM content, and a lower TC/TN ratio. Qualitative SOM transformation during aerobic SOM transformation after draining the studied peatlands consisted of an increase in the amount of labile fractions and humic substances and a decrease in the lipid and residual fractions. The research results have shown that the HAs properties depended on the depth. HAs from topsoil horizons, compared to peat horizons, were characterized by a lower “degree of maturity,” as reflected by the values of atomic ratios (H/C, O/C) and absorbance coefficients (A_4/6 and ΔlogK). It was found that the share of the distinguished SOM fractions and HAs properties were closely correlated with the physical and chemical properties of the soils. The study demonstrated the usefulness of the sequential carbon fractionation method for assessing the effects of dewatered peat transformation. The obtained results could contribute to the development of good practices ensuring high quality of organic matter and stability of ecosystems, as well as to the development of methods for limiting the mineralization of organic matter (SOM), greenhouse gas emissions, and the loss of organic soils in agricultural areas. Full article

Słowiński National Park is one of the 23 national parks in Poland and one of the two situated on the Baltic Coast in the country. It was established in 1967 to protect the most valuable ecosystems: coastal lakes, marshes, peat bogs, meadows, forests, and, above all, the dune belt of the Łebska Spit with its unique moving dunes. We aimed to 1. determine the species diversity and structure of thrips assemblages in the most important biotopes of the Park; 2. determine the geographical distribution and food preferences of thrips species; and 3. determine which environmental factors influence the diversity of insect assemblages and which thrips species distinguish these assemblages. The method used in the quantitative research was based on the use of a scoop method; it was supplemented by qualitative research (shaking branches of trees and searching for insects on their host plants). The studies were carried out in 1991 and 1999–2001 in fourteen plant associations. A total of 90 thrips species (nearly 40% of the Polish fauna) were recorded, including 71 in quantitative and 74 in qualitative samples. The study also revealed a significant correlation between the thrips assemblage composition and the following environmental factors: soil moisture, light intensity, general nutrient availability, and soil salinity. In addition, the thrips species with the most significant impact on assemblage composition were identified. The relatively high number of species found, including Taeniothrips zurstrassenii Zawirska, a species new to science, and others rarely recorded in Poland, highlights the value of the SNP habitat diversity in maintaining high Thysanoptera diversity. Full article

This paper presents a new, quick method for testing the content of magnetic forms of iron in organic soils. These forms are an important marker of changes occurring in the environment. This method is based on impedance spectroscopy of a measuring coil inside which the tested material is placed—the material serves as the core of the coil. Unlike EIS (electrochemical impedance spectroscopy), the new method does not use electrodes, is sensitive to magnetic forms of iron, and is non-contact (the measuring current does not flow through the tested material). The results of research on three materials, including brown peat and silt with plant detritus, are presented in this paper. The results showed that changes in the standardized components of the measuring coil impedance in the frequency range of 100–135 kHz enable the determination of the content of ferromagnetic iron oxide (Fe₃O₄). The proposed method is very sensitive to soil oxide content in the range of 0% to 8%. Additionally, elemental composition analysis was performed using ICP-AES (inductively coupled plasma–atomic emission spectroscopy), which allowed for comparison of iron and other metal content with impedance measurement results. The final results confirm the usefulness of impedance spectroscopy as a non-destructive method for studying sedimentary environments and assessing their mineral properties. Full article

Peatlands play a critical role in global and regional climate regulation by functioning as long-term carbon sinks, regulating hydrology, and modulating land–atmosphere energy exchange. Intact peat ecosystems store large amounts of organic carbon and stabilize local climate through high water retention and evapotranspiration, whereas peatland degradation disrupts these functions and can transform peatlands into significant sources of greenhouse gas emissions and climate extremes such as drought and fire. Indonesia contains approximately 13.6–40.5 Gt of carbon, around 40% of which is stored on the island of Sumatra. However, tropical peatlands in this region are highly vulnerable to climate anomalies and land-use change. This study investigates the impacts of major climate anomalies—specifically El Niño and positive Indian Ocean Dipole (pIOD) events in 1997/1998, 2015/2016, and 2019—on peatland cover change across South Sumatra, Jambi, Riau, and the Riau Islands. Landsat 5 Thematic Mapper and Landsat 8 Operational Land Imager/Thermal Infrared Sensor imagery were analyzed using a Random Forest machine learning classification approach. Climate anomaly periods were identified using El Niño-Southern Oscillation (ENSO) and IOD indices from the National Oceanic and Atmospheric Administration. To enhance classification accuracy and detect vegetation and hydrological stress, spectral indices including the Normalized Difference Vegetation Index (NDVI), Modified Soil Adjusted Vegetation Index (MSAVI), Normalized Difference Water Index (NDWI), and Normalized Difference Drought Index (NDDI) were integrated. The results show classification accuracies of 89–92%, with kappa values of 0.85–0.90. The 2015/2016 El Niño caused the most severe peatland degradation (>51%), followed by the 1997/1998 El Niño (23–38%), while impacts from the 2019 pIOD were comparatively limited. These findings emphasize the importance of peatlands in climate regulation and highlight the need for climate-informed monitoring and management strategies to mitigate peatland degradation and associated climate risks. Full article

The issue of formulating scientifically sound standards for mercury (Hg) content in Arctic soils is becoming increasingly pertinent in view of the rising human impact and climate change, which serve to augment the mobility of Hg compounds and their involvement in biogeochemical processes. In the absence of uniform criteria for regulating Hg concentrations, it is particularly important to determine its geochemical baseline values and the factors that determine the spatial and vertical distribution of the element in the soil profile. The study conducted a comprehensive investigation of Hg content and patterns of its distribution in various types of tundra soils in the European North-East of Russia. The mass fraction of total Hg was determined by atomic absorption spectrometry, and the spatial features of accumulation were analysed using geoinformation technologies. The distribution of Hg in the soils of the tundra zone was found to be distinctly mosaic in nature, determined by the combined influence of organic matter, granulometric composition, and hydrothermal conditions. It has been established that the complex influence of the physicochemical properties of soils determines the spatial heterogeneity of Hg distribution in the soils of the tundra zone. The most effective Hg accumulators are peat and gley horizons enriched with organic matter and physical clay fraction, while in Podzols, vertical migration of Hg is observed in the presence of a leaching water regime. In order to standardise geochemical baseline Hg values, a 95% upper confidence limit (UCL_95%) is proposed. This approach enables the consideration of natural background fluctuations and the exclusion of extreme values. The results obtained provide a scientific basis for the establishment of standards for Hg content in background soils of the Arctic. Full article