Search Results (605)

Soil amendments are widely applied to improve soil fertility and structure, yet their performance in cold regions is constrained by low accumulated temperatures, frequent freeze–thaw (FT) cycles, and permafrost sensitivity. In this review, ‘cold regions’ refers to high-latitude and high-altitude areas characterized by long winters and seasonally frozen soils and/or permafrost. We screened the peer-reviewed literature using keyword-based searches supplemented by backward/forward citation tracking; studies were included when they assessed amendment treatments in cold region soils and reported measurable changes in physical, chemical, biological, or environmental indicators. Across organic, inorganic, biological, synthetic, and composite amendments, the most consistent benefits are improved aggregation and nutrient retention, stronger pH buffering, and the reduced mobility of potentially toxic elements. However, effectiveness is often site-specific and may be short-lived, and unintended risks—including greenhouse gas emissions, contaminant accumulation, and thermal disturbances—can offset gains. Cold-specific constraints are dominated by limited thermal regimes, FT disturbance, and the trade-off between surface warming for production and permafrost protection. We therefore propose integrated countermeasures: prescription-based amendment portfolios tailored to soils and seasons; the prioritization and screening of local resources; coupling with engineering and land surface strategies; a minimal cold region MRV loop; and the explicit balancing of agronomic benefits with environmental safeguards. These insights provide actionable pathways for sustainable agriculture and ecological restoration in cold regions under climate change. Full article

In this study, we investigated the bioaccumulation of 17 heavy metals—titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, antimony, cadmium, tin, mercury, and lead—in the liver and kidney tissues of the least weasel, based on samples (n = 129) collected from adjacent intensive agricultural environments in Hungary and Austria. To explore the structure of the bioaccumulation data, principal component analysis (PCA) was performed. The PCA score plot based on national-level elemental profiles revealed no differentiation between Austria and Hungary. In contrast, a clear and unambiguous distinction was observed between the two examined tissues within individuals for Ti, Mn, Fe, Co, Zn, Se, Mo, Cd, and Hg (p < 0.001), as well as for Pb (p < 0.05). The biological relevance of the accumulation results was adjusted using the MCID approach. As heavy metal accumulation in the least weasel has not yet been investigated, our results could only be compared with concentrations reported for predatory mammals occurring in similar habitats. Based on the relevant literature, we highlight predominantly anthropogenic exposure pathways affecting agroecosystems—organic and mineral fertilizers, plant protection products, wastewater, and fossil fuels—which underscore the necessity of regular biomonitoring studies in agricultural landscapes. Full article

The rapid increase in organic waste generation poses significant environmental challenges and highlights the limitations of conventional waste management practices. In this context, black soldier fly (Hermetia illucens) larvae (BSFL) have emerged as a promising biological tool for valorizing organic residues within circular bioeconomy frameworks. This review provides an integrated analysis of BSFL-based bioconversion systems, focusing on the biological characteristics of BSFL, suitable organic waste streams, and the key process parameters influencing waste reduction efficiency, larval biomass production, and frass (the residual material from larval bioconversion) yield. The performance of BSFL in converting organic waste is assessed with emphasis on substrate characteristics, environmental conditions, larval density, and harvesting strategies. Environmental and economic implications are discussed in comparison with conventional treatments such as landfilling, composting, and anaerobic digestion. Special attention is given to the nutritional composition of BSFL and the valorization of larvae as sustainable protein and lipid sources for animal feed and emerging human food applications, while frass is highlighted as a nutrient-rich organic fertilizer and soil amendment. Finally, current challenges related to scalability, safety, regulation, and social acceptance are highlighted. By linking waste management, resource recovery, and sustainable protein production, this review clarifies the role of BSFL and frass in resilient and resource-efficient food and waste management systems. Full article

Hair dyes are widely used across all socioeconomic groups and regions worldwide. However, some studies indicate that these products contain substances known to be toxic to a wide variety of organisms. Moreover, dyeing practices generate effluents that may carry the toxicity of hair dyes into the environment. Due to these facts, there is great concern about the impacts these products may have on the environment, as well as on the health of their users and professionals in the field of cosmetology. This scoping review analyzed 184 publications from major databases (PubMed, SciELO, Scopus, Google Scholar, and MEDLINE). Ultimately, 126 scientific studies published between 1981 and 2024 were included based on methodological rigor and their relevance to the One Health framework. According to the literature, the components of hair dyes can induce adverse responses in biological systems, ranging from reversible topical irritations to severe systemic effects. Among the studies evaluated, more than half reported significant toxicological or genotoxic associations related to oxidative dye components such as p-phenylenediamine and its derivatives. These compounds are frequently associated with various types of human cancers, including breast, prostate, bladder, skin, ocular cancers, and brain tumors. In addition to their effects on humans, hair dyes exhibit ecotoxicity, which may threaten the maintenance of ecosystems exposed to their residues. The reported environmental impacts result from effluent emissions after successive hair washes that release unreacted dye residues. Due to the low biodegradability of these compounds, conventional wastewater treatment methods are often ineffective, leading to environmental accumulation and changes in aquatic ecosystems, soil fertility, and trophic balance. Data on the toxicity of hair dye effluents remain scarce and sometimes contradictory, particularly regarding the effects of their transformation products and metabolites. Overall, the evidence underscores the need for continuous monitoring, updated risk assessments, and the adoption of advanced treatment technologies specific to beauty salon effluents. The information presented in this work may support further studies and guide public management agencies in developing policies for mitigating the impacts of hair dye pollutants within the One Health perspective. Full article

Wildfires are increasingly frequent and intense due to climate change, resulting in degraded soils with diminished microbial activity, reduced water retention, and low nutrient availability. In many regions, previously restored areas face repeated burning events, which further exhaust soil fertility and limit the potential for natural regeneration. Traditional reforestation approaches such as seed scattering or planting seedlings often fail in these conditions due to extreme aridity, erosion, and lack of biological support. To address this multifaceted problem, this study proposes a living, biodegradable hydrogel that integrates an engineered soil-beneficial microorganism consortium, designed to deliver beneficial compounds and nutrients combined with endemic plant seeds into a single biopolymeric matrix. Acting simultaneously as a biofertilizer, soil conditioner, and reforestation aid, this 3-in-1 system provides a microenvironment that retains moisture, supports microbial diversity restoration, and facilitates plant germination even in nutrient-poor, arid soils. The concept is rooted in circular economy principles, utilizing polysaccharides from food industry by-products for biopolymer formation, thereby ensuring environmental compatibility and minimizing waste. The encapsulated microorganisms, a Bacillus subtilis strain and a Nostoc oryzae strain, are intended to enrich the soil with useful compounds. They are engineered based on synthetic biology principles to incorporate specific genetic modules. The B. subtilis strain is engineered to break down large polyphenolic compounds through laccase overexpression, thus increasing soil bioavailable organic matter. The cyanobacterium strain is modified to enhance its nitrogen-fixing capacity, supplying fixed nitrogen directly to the soil. After fulfilling its function, the matrix naturally decomposes, returning organic matter, while the incorporation of a quorum sensing-based kill-switch system is designed to prevent the environmental escape of the engineered microorganisms. This sustainable approach aims to transform post-wildfire landscapes into self-recovering ecosystems, offering a scalable and eco-friendly alternative to conventional restoration methods while advancing the integration of synthetic biology and environmental engineering for climate resilience. Full article

Global sustainability challenges call for assessing the environmental impacts of agricultural production systems, which are crucial to meeting the nutritional demands of a growing global population. This study uses the PRISMA model and a checklist to provide a systematic literature review of LCA studies on durum wheat and legume cultivation; it highlights the impacts of monoculture cultivation with crop rotation on key environmental indicators. An analysis was conducted to examine the environmental burdens of these crops under conventional and organic systems and explored how using different functional units (mass- or area-based) influences the environmental outcomes. The results reveal that integrating legumes into crop rotations significantly enhances environmental sustainability by reducing reliance on synthetic nitrogen fertilizers through biological nitrogen fixation, resulting in substantial environmental benefits, reaching a reduction in GWP from 6 to 45% compared to monoculture durum wheat cultivation. Conventional agriculture achieves higher crop yields; however, its reliance on chemical inputs and substantial energy consumption results in greater overall environmental impact. Conversely, while organic farming has a lower impact per unit of land, its lower productivity results in higher emissions per unit of output. Full article

Nowadays, biowaste valorization is a key point in the circular economy. Digestate and compost from organic waste treatment can be used as nutrient-rich fertilizers. In Europe, the use of biowaste-derived fertilizers is promoted by the European Fertilizer Regulation (EU) 2019/1009, which requires verification of their biological stability through regulated indices; however, it is not clear whether the proposed indices and threshold values indicate the same level of stability and what correlations there are between them. This study compared four biological stability indices, namely Oxygen Uptake Rate (OUR), Self-Heating (SH), Residual Biogas Potential (RBP), and Dynamic Respirometric Index (DRI), which were tested on 50 samples of compost and digestate. Overall, the results revealed that most of the compost and digestate samples were quite far from European standards. On the contrary, the RBP test seemed to be less stringent than the other indices, since a much larger number of samples was closer to or in compliance with the established threshold. Data analysis using Pearson’s coefficients showed a strong linear correlation between the indices. Nevertheless, the linear regression predictive model based on experimental data demonstrated that the indices could not represent the same level of stability, providing poor consistency and variability in the predicted values and established threshold. In particular, the DRI test appeared to be more severe than the other aerobic indices. This work could provide valuable support in improving evaluation criteria and promoting a sustainable use of compost and digestate as organic fertilizers from a circular economy perspective. Full article

The long-term effects of integrated nutrient management (INM) on crop performance and soil health—particularly within sub-humid environments—remain insufficiently explored. This research aimed to quantify the relationship between the soil quality index (SQI) and overall system productivity. The SQI represents a numerical indicator of soil functioning and its biological and chemical integrity, while system productivity reflects the economic yield generated by the cropping system. A long-term experiment initiated in 1972 formed the foundation for this study, which was conducted from 2019 to 2021 and included eleven nutrient management treatments. These comprised the following treatments: inorganic fertilizers alone (100% NPK, 150% NPK, 100% NP, 100% N, and 100% NPK without sulfur); combinations of organic and inorganic inputs (50% NPK + FYM and 100% NPK + FYM); lime with inorganic fertilizers (100% NPK + lime); zinc with inorganics (100% NPK + Zn); hand weeding with inorganics (100% NPK + HW); an unfertilized control. The study was implemented in a maize–wheat rotation under the sub-humid climatic conditions of Palampur, Himachal Pradesh, India. System productivity was estimated using wheat grain equivalent yield, and SQI values were generated from selected soil properties. These indicators—along with the sustainable yield index (SYI)—were applied to assess the effectiveness of each treatment. The results showed that the 100% NPK + FYM combination produced the highest SQI, followed by 100% NPK + lime, whereas the 100% N treatment yielded the lowest value. Overall, the findings highlight the crucial role of adopting sustainable nutrient management practices to maintain soil quality and optimize productivity in sub-humid agricultural systems. Full article

Biological N₂ fixation (BNF) and ratoon rice growth are biological processes that mediate N and C cycling in rice paddy ecosystems, but their contributions to paddy soil fertility have rarely been evaluated in a quantitative and unified manner. In this study, we analyzed the contribution of BNF and ratoon rice growth to soil N fertility at six rice paddy sites in four prefectures of Japan, combining 2-year field monitoring and simulation using the DNDC-Rice biogeochemistry model. Across the sites and years, ratoon rice was found to accumulate up to 30 kg N ha⁻¹ without fertilization and irrigation after main rice harvest. BNF was not measured but estimated to be 33–63 kg N ha⁻¹ yr⁻¹ at the six sites, by applying a newly built BNF model after calibration against a literature dataset. Based on the simulations using DNDC-Rice under typical local management strategies, we estimated the following contributions of BNF and ratoon rice to soil N fertility, with variations based on the climate, soil properties, and management, as follows: (a) BNF and ratoon rice contributed 4–33% and 3–23% of the N supply from soil during the main rice season, respectively. (b) While BNF contributed 3–29% of the main rice N uptake, that from ratoon rice was much lower (6% or less), presumably because the decomposition of ratoon rice residue induced N immobilization during the main rice season. (c) Although the major part of N gain by BNF was being lost via denitrification and N leaching, BNF was contributing up to 6.6% of the organic N pool at the 0–30 cm soil layer. Ratoon rice was working to save N loss by reducing N leaching, consequently contributing up to 3.3% of the soil N pool. These findings provide quantitative insights into what roles BNF and ratoon rice play in paddy soil fertility. Full article

Soil fertility plays a crucial role in crop productivity, particularly in cocoa cultivation, which is highly dependent on soil quality that directly influences both productivity and sustainability. Understanding how to achieve and maintain soil fertility on cocoa farms is fundamental to sustaining higher yields. Cocoa production in Ghana and Togo remains low, at 350–600 kg/ha, compared to the potential yield of over 1–3 tons per hectare. Given the growing demand for cocoa and limited arable land, adequate soil nutrients are essential to optimise productivity. Soil fertility indices (SFIs) have been widely used as soil metrics by integrating multiple physical, chemical, and biological soil properties. In this study, standard analytical methods were employed to evaluate the SFI through laboratory analyses of 49 surface soil samples collected at a depth of 0–30 cm with an auger. Eleven soil chemical indicators were analysed: pH (water), organic matter (OM), potassium (K), calcium (Ca), magnesium (Mg), available phosphorus (P), total nitrogen (N), cation exchange capacity (CEC), electrical conductivity (EC), and carbon-to-nitrogen ratio (C/N). Principal component analysis, followed by normalisation, was used to select a minimum dataset, which was then integrated into an additive SFI. Results indicated that N, Ca, Mg, CEC, and pH were within the optimal range for most surveyed locations (96%, 94%, 92%, 73%, and 63%, respectively), while OM and C/N were within the optimal range in approximately half of the study area. Available P, K, and C/N were highly deficient in 100%, 67%, and 96% of surveyed locations, respectively. Soil fertility varied significantly among locations (p = 0.007) and was generally low, ranging from 0.15 to 0.66. Only 20% of the soils in the study area were classified as adequately fertile for cocoa cultivation. Therefore, it is necessary to restore soil nutrient balance, especially the critically low levels of K and P, through appropriate management practices that improve fertility over time and help close the yield gap. Full article

Three organic soil amendments of different origins (chicken manure, fungal biomass obtained through biological fermentation, and a leonardite-based humic acid product) were applied to young chestnut trees, alongside mineral fertilizer, which when applied alone served as the control. During the second year, bud break pattern, photosynthetic activity, leaf carbohydrate concentrations, soil properties, and leaf nutrient content were evaluated across multiple sampling events. Sampling time significantly influenced most measured parameters. The addition of organic amendments accelerated bud break, influenced plant nutrient uptake, and modified soil properties. Notably, soil organic matter increased following chicken manure and fungal biomass applications, available phosphorus decreased under fungal biomass and leonardite-based humic acids (to 14.5 and 12.4 ppm, respectively, compared to 17.5 ppm in the mineral fertilizer control), and soil iron concentrations tripled under leonardite-based humic acids relative to the control. However, no significant effects were observed on photosynthetic performance or leaf carbohydrate concentrations. Discriminant and hierarchical cluster analyses revealed clear differences among amendments, with the humic acid-based product exerting distinct effects. As there are not many data available in the literature on the efficacy of organic amendments in chestnut cultivation, the present results underscore the importance of the site-specific selection of organic amendments, tailored to soil characteristics (in the present trial, an acidic soil) and specific nutritional objectives to optimize tree physiological performance. Full article

Rapid urbanization has intensified nitrate pollution in megacity rivers, posing severe challenges to urban water governance and sustainable nitrate management. This study presents nitrate dual-isotope signatures (δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻) from surface water samples collected during the wet season from the Yongding River (YDR) and Chaobai River (CBR) in the Beijing–Tianjin–Hebei megacity region of North China. Average concentrations of nitrate (as NO₃⁻) were 8.5 mg/L in YDR and 12.7 mg/L in CBR. The δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ values varied from 6.1‰ to 19.1‰ and −1.1‰ to 10.6‰, respectively. The spatial distribution of NO₃⁻/Cl⁻ ratios and isotopic data indicated mixed sources, primarily sewage and manure in downstream sections and agricultural inputs in upstream areas. Isotopic evidence revealed widespread nitrification processes and could have potentially localized denitrification under low-oxygen conditions in the lower YDR. Bayesian mixing model (MixSIAR) results indicated that sewage and manure constituted the main nitrate sources (49.4%), followed by soil nitrogen (23.7%), chemical fertilizers (19.2%), and atmospheric deposition from rainfall (7.7%). The self-organizing map (SOM) further revealed three nitrate regimes, including natural and agricultural, mixed, and sewage dominated conditions, indicating a clear downstream gradient of increasing anthropogenic influence. The results suggest that efficient nitrogen management in megacity rivers requires improving biological nutrient removal in wastewater treatment, regulating fertilizer application in upstream areas, and maintaining ecological base flow for natural denitrification. This integrated framework provides a quantitative basis for nitrate control and supports sustainable water governance in highly urbanized watersheds. Full article

Agroecology is increasingly shaped by the convergence of traditional knowledge, farmers’ lived experiences, and scientific research, fostering a plural dialog that embraces the ecological and socio-political complexity of agricultural systems. Within this framework, soil biodiversity is essential for maintaining ecosystem functions, with soil microbiology, and particularly arbuscular mycorrhizal fungi (AMF), playing a pivotal role in enhancing soil fertility, plant health, and agroecosystem resilience. This review explores the synergy between agroecological practices and AMF by examining their ecological, economic, epistemic, and territorial contributions to sustainable agriculture. Drawing on recent scientific findings and Latin American case studies, it highlights how practices such as reduced tillage, crop diversification, and organic matter inputs foster diverse and functional AMF communities and differentially affect their composition and ecological roles. Beyond their biological efficacy, AMF are framed as relational and socio-ecological agents—integral to networks that connect soil regeneration, food quality, local autonomy, and multi-species care. By bridging ecological science with political ecology and justice in science-based knowledge, this review offers a transdisciplinary lens on AMF and proposes pathways for agroecological transitions rooted in biodiversity, cognitive justice, and territorial sustainability. Full article

Livestock manure is a major source of environmental pollution and greenhouse gas emissions if improperly managed. Aerobic composting represents a sustainable approach to manure recycling that can stabilize organic matter, mitigate carbon loss, and recover nutrients for agricultural use. In this study, sheep manure was mixed with sawdust to optimize the carbon-to-nitrogen (C/N) ratio and enhance aeration, and the mixture was subjected to aerobic composting with a cellulose-degrading microbial inoculant. To rigorously evaluate the biological effects, a control treated with sterilized inoculant was included to eliminate nutrient inputs from the carrier matrix. The inoculant significantly improved composting performance by extending the thermophilic phase by five days and reducing the C/N ratio to 19.8 on day 32, thereby shortening the composting cycle. Moreover, microbial inoculation enhanced nutrient retention, resulting in a 20.14% increase in total nutrient content, while the germination index (GI) reached 89.75%, indicating high compost maturity and reduced phytotoxicity. Microbial community analysis revealed that cellulose-degrading inoculants significantly altered microbial richness and diversity and accelerated community succession. Redundancy analysis (RDA) and hierarchical partitioning analysis showed that total organic carbon (TOC) and GI were the main environmental drivers of bacterial community dynamics, whereas pH and GI primarily regulated fungal community succession. These findings suggest a strong link between compost maturity and microbial community restructuring. This study demonstrates that cellulose-degrading microbial inoculation accelerates the composting of sheep manure, enhances organic matter degradation, and improves fertilizer efficiency while reducing the phytotoxicity of the final product. Full article

The interaction between organic and inorganic nutrients, bacterial communities, and soil fertility has been well documented over time. Conventional agricultural systems heavily utilize both inorganic and organic fertilizers, each exerting distinct effects on soil microbial dynamics and plant growth. The objective of our experiments was to identify the most effective fertilization strategy for improving the biological quality of a microbiologically impoverished and low-productivity soil. To this end, four fertilization strategies were evaluated: (i) organic fertilizers characterized by a high content of organic carbon (Fertil 4-5-7—variant 1); (ii) organic fertilizers with 12% organic nitrogen from proteins (Bio Ostara N—variant 2) (iii) combined inorganic–organic fertilizers (P35 Bio—variant 3) and (iv) mineral (inorganic) fertilizers (BioAktiv—variant V4). This study aimed to assess the short-term effects of fertilizers with varying chemical compositions on the density of cultivable heterotrophic bacteria and their associated dehydrogenase (DH) activity in a petrocalcic chernozem soil containing pedogenic carbonates. Soil sampling was conducted according to a randomized block design, comprising four replicates per treatment (control plus four fertilizer types). The enumeration of cultivable bacteria was performed using Nutrient Agar and A2R Agar media, whereas dehydrogenase activity (DHA) was quantified based on the reduction of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) to 1,3,5-triphenyl-tetrazolium formazan (TPF) by bacterial dehydrogenase enzymes. Marked differences were observed in both parameters between the plots amended with inorganic fertilizers and those treated with organic fertilizers, as well as among the organic fertilizer treatments of varying composition. The most pronounced increases in both bacterial density and dehydrogenase activity (DHA) were recorded in the plots receiving the fertilizer with a high organic nitrogen content. In this treatment, the maximum bacterial population density reached 6.25 log₁₀ CFU g⁻¹ dry soil after approximately two months (May), followed by a significant decline starting in July. In contrast, DHA exhibited a more rapid response, reaching its peak in April (42.75 µg TPF g⁻¹ soil), indicating an earlier DHA activation of microbial metabolism. This temporal lag between the two parameters suggests that enzymatic activity responded more swiftly to the nutrient inputs than did microbial biomass proliferation. For the other two organic fertilizer variants, bacterial population dynamics were broadly similar, with peak densities recorded in June, ranging from 5.98 log₁₀ CFU g⁻¹ soil (V3) to 6.03 log₁₀ CFU g⁻¹ soil (V1). A comparable trend was observed in DHA: in V3, maximum DHA was attained in June (30 µg TPF g⁻¹ soil), after which it remained relatively stable, whereas in V1, it peaked in June (24.05 µg TPF g⁻¹ soil) and subsequently declined slightly toward the end of the experimental period. Overall, the temporal dynamics of bacterial density and DHA demonstrated a strong dependence on the quality and biodegradability of the organic matter supplied by each fertilizer. Both parameters were consistently lower under inorganic fertilization compared with organic treatments, suggesting that the observed increases in microbial density and activity were primarily mediated by the enhanced availability of organic substrates. The relationship between the density of culturable heterotrophic bacteria and dehydrogenase (DH) activity was strongly positive (r = 0.79), indicating a close functional linkage between bacterial density and oxidative enzyme activity. This connection suggests that the culturable fraction of the heterotrophic microbial community plays a key role in the early stages of organic matter mineralization derived from the applied fertilizers, particularly in the decomposition of easily degradable substrates. Full article