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Abstract: Although several studies have examined the effect of sewage sludge (SS) application on various legume crops, there is insufficient information confirming the agronomic and environmental sustainability of SS usage in a broad bean cultivation systems. Therefore, a greenhouse experiment was completed to assess the soil heavy metal (HM) pools, growth, yield, and HM uptake of Faba sativa Bernh. (broad bean) grown in the agricultural soils supplemented with SS in comparison to control soils (nonamended). The experimental design was completely randomized with six replicates. The amendment with SS significantly elevated the organic matter (OM) content, soil salinity and Al, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn concentrations, although the soil pH decreased. As allowed by the Council of European Communities, the concentrations of the determined HMs were less than the accepted limit for SS used in agriculture. Generally, SS applications of up to 120 t/ha produced a considerable increase in the growth measurements and biomass of broad bean. However, the broad bean biomass, shoot height, number of branches, root length, absolute growth rate, number of leaves, and leaf area declined in reaction to a rate of 150 t/ha. The HM concentrations in various tissues of broad bean plants exposed to SS were significantly higher than those in the untreated plants. However, most HM concentrations were inside the permissible limits and did not overcome the maximum levels of phytotoxic. The broad bean was recognized by a bioaccumulation factor less than 1.0 for the majority of the HMs. The translocation factors for the determined HMs (excluding for Al, Co, and Pb in stems and leaves) were less than 1.0. Therefore, the SS utilized in this study could be used as a fertilizer for broad bean crops and could as well act as a replacement manner for SS elimination. [ABSTRACT FROM AUTHOR]

Insect pollinators provide many essential ecosystem services including pollination, and many others. However, pollinating insects are currently facing potential threats on an unprecedented scale with many species facing decline. Honeybee Apis mellifera comprise nearly 68% of those affected insect pollinators. Irrational Insecticides application, with special reference to neonicotinoides group is one of the main causes of this decline. The main objective of the current study is to investigate the impact of some insecticides application on the activity of broad bean flower-visiting bees. Tested inseticides were thiamethoxam, acetamiprid, thiacloprid (neonicotinoids), spinosyns A and D, beside some organophosphates. Changes in the daily activity of bees visiting broad bean flowers following insecticide application was recorded and compared to their activity before application, throughout until the end of blooming season. [ABSTRACT FROM AUTHOR]

The substantial release of NH 3 during composting leads to nitrogen (N) losses and poses environmental hazards. Additives can mitigate nitrogen loss by adsorbing NH 3 /NH 4 , adjusting pH, and enhancing nitrification, thereby improving compost quality. Herein, we assessed the effects of combining bacterial inoculants (BI) (1.5%) with tricalcium phosphate (CA) (2.5%) on N retention, organic N conversion, bacterial biomass, functional genes, network patterns, and enzyme activity during kitchen waste (KW) composting. Results revealed that adding of 1.5%/2.5% (BI + CA) significantly (p < 0.05) improved ecological parameters, including pH (7.82), electrical conductivity (3.49 mS/cm), and N retention during composting. The bacterial network properties of CA (265 node) and BI + CA (341 node) exhibited a substantial niche overlap compared to CK (210 node). Additionally, treatments increased organic N and total N (TN) content while reducing NH 4 + -N by 65.42% (CA) and 77.56% (BI + CA) compared to the control (33%). The treatments, particularly BI + CA, significantly (p < 0.05) increased amino acid N, hydrolyzable unknown N (HUN), and amide N, while amino sugar N decreased due to bacterial consumption. Network analysis revealed that the combination expanded the core bacterial nodes and edges involved in organic N transformation. Key genes facilitating nitrogen mediation included nitrate reductase (nasC and nirA), nitrogenase (nifK and nifD), and hydroxylamine oxidase (hao). The structural equation model suggested that combined application (CA) and microbial inoculants enhance enzyme activity and bacterial interactions during composting, thereby improving nitrogen conversion and increasing the nutrient content of compost products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study aimed to explore the main pathway of humic acid (HA) formation during the thermophilic phase (TP) of aerobic fermentation, clarify the contribution of Maillard reaction. These experiments were carried out on cow dung, chicken manure and rice straw. Results indicated that the maximum temperature reached 60.2℃ during TP led to a sharp decrease in microbial abundance, while the production of HA increased. The network analysis indicated that microorganisms did not participate in the formation of HA and may be dominated by abiotic pathways. In addition, proteins and sugars were consumed at the highest rate during TP, and the trends were similar to HA formation. These findings suggested that the formation of HA has relationship to Maillard reaction, because TP provided suitable reaction conditions for Maillard reaction. Therefore, these results elucidated the contribution of Maillard reaction in HA formation during TP, and provided theoretical support for directional humification., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Transforming organic waste into stable carbon by composting is an eco-friendly way. However, the complex environment, huge microbial community and complicated metabolic of composting have limited the directional transformation of organic carbon, which is also not conducive to the fixation of organic carbon. Therefore, this review is based on the formation of humus, a stable by-product of composting, to expound how to promote carbon fixation by increasing the yield of humus. Firstly, we have clarified the transformation regularity of organic matter during composting. Meanwhile, the microhabitat factors affecting microbial catabolism and anabolism were deeply analyzed, in order to provide a theoretical basis for the micro habitat regulation of directional transformation of organic matter during composting. Given that, a method to adjust the directional humification and stabilization of organic carbon has been proposed. Hoping the rapid reduction and efficient stabilization of organic waste can be realized according to this method., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The aim of this study was to explore the effects of adding biochar and montmorillonite alone on the correlations between bacteria and bioavailability of heavy metals (HM) during chicken manure composting. Three composting experiments were conducted, containing the without ameliorant, 10% biochar and 10% montmorillonite. The results showed that biochar and montmorillonite ameliorants significantly reduced the bioavailability of Cu by 90.3%, 81.2%, while that of Zn by 11.7%, 15.6%, respectively. Meanwhile, they also significantly changed bacterial community structure and enhanced the correlation between bacterial bands (i.e., 19, 24, 26 and 30) and HM fractions. This correlation was validated in network analysis. Structural equation models further confirmed that bacteria had a complete and effective pathway to influence the bioavailability of HM. In summary, this study suggested that biochar and montmorillonite additions were an effective regulation method to reduce the bioavailability of HM from composting system., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This study was conducted to investigate the toxicity of aldicarb, cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl toward mature Aporrectodea caliginosa earthworms. The effects of the LC(25) values of these pesticides on the growth rate in relation to glucose, soluble protein, and activities of glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), acid phosphatase (AcP), and alkaline phosphatase (AIP) were also studied. The results showed that aldicarb was the most toxic of the tested pesticides, followed in order by cypermethrin, profenofos, chlorfluazuron, atrazine, and metalaxyl. A reduction in growth rate was observed in all pesticide-treated worms, which was accompanied by a decrease in soluble protein and an increase in transaminases and phosphatases. Relationships between growth rate, protein content, transaminases, and phosphatases provided strong evidence for the involvement of pesticidal contamination in the biochemical changes in earthworms, which can be used as a bioindicator of soil contamination by pesticides., (Copyright 2003 Wiley Periodicals, Inc.)