Weixi Shu

Biochar provides multiple agronomic benefits, including carbon sequestration and reduced nutrient leaching. This study evaluated the effects of wood‐ and crab shell‐based biochar, enriched with cow urine or liquid seaweed extract, on soil nitrogen (N) dynamics and early spring wheat ( Triticum aestivum ) growth. Three experiments were conducted: (1) nutrient sequestration analysis of enriched biochar, (2) a soil column leaching experiment, and (3) germination experiments. Biochar was produced via pyrolysis at 400°C, ground to < 1 mm, and enriched by immersion in liquid amendments for 48 h. Enrichment increased nitrate (NO ₃ ⁻ ) and ammonium (NH ₄ ⁺ ) content, particularly in wood biochar enriched with cow urine. In the soil column experiment, both biochars significantly reduced NO ₃ ⁻ and NH ₄ ⁺ leaching compared to urea and unamended control treatments. When cow urine was used as a liquid enrichment amendment, crab shell biochar reduced NH ₄ ⁺ leaching by 89.7% and NO ₃ ⁻ by 85.1%, while wood biochar reduced NH ₄ ⁺ by 94.8% and NO ₃ ⁻ by 87.8% relative to non‐amended soil. Seaweed extract‐enriched biochar also reduced inorganic N leaching compared to non‐amended soil, though reductions were less pronounced than those observed with cow urine enrichment. In germination experiments, adding 1.00 g of wood biochar per pouch significantly increased shoot length by 29.5% compared to the non‐biochar control, whereas higher rates of crab shell biochar resulted in a negative effect, reducing shoot length by 35.0% compared to the control. Cow urine‐enriched wood biochar and liquid seaweed extract alone produced the longest shoots. Among treatments, cow urine‐enriched wood biochar showed the highest N retention and greatest stimulation of shoot growth. These findings indicate that enriched biochar, particularly cow urine‐enriched wood biochar, can act as effective slow‐release fertilizers, reducing N leaching and enhancing early plant growth.

Antibiotic resistance genes (ARGs) represent a critical global public health threat. Effective resistome management within the One Health framework requires a comprehensive understanding of the sources and movement of ARGs across environmental media. This study provides a detailed analysis of resistome characteristics and dynamics in global landfill systems. Landfill systems were found to harbor diverse and highly mobile ARGs, with multidrug‐resistant genes (MDRGs) comprising 32.63% of total ARGs, and comparable or even higher levels of associated ARG subtypes than in other environmental media, such as acidic mine wastewater. The ARG density on plasmids was 3.5 times higher than that on chromosomal sequences, with five times more abundant ARG‐carrying plasmid‐associated contigs in landfill systems than that in wastewater. At the metagenome‐assembled genome level, members of the phylum Pseudomonadota were identified as the most abundant hosts (29.72%), harboring 47.74% and 56.47% of the total ARGs and MDRGs, respectively. Genomic analysis of 35 Pseudomonas spp. strains revealed unique Pseudomonas species in landfill systems, including P. aeruginosa . Resistome flow pathways were further mapped, including inflows into landfill (via soil, wastewater, freshwater, and the human and pig gut), movement within landfills (across landfill refuse, leachate, and airborne particles), and outflows from landfills (via landfill leachate effluent, gas emissions, and refuse evacuation). The results emphasized diverse resistome development and movement within landfill systems, ultimately contributing to the environmental spread of ARGs. Thus, our study highlights the urgent need for comprehensive policies and management strategies to mitigate resistome proliferation at every stage of municipal solid waste management.

The United Nations has identified municipal solid waste (MSW) landfills as significant reservoirs of antibiotic resistance genes (ARGs). Although ARG profiles, their primary drivers, and associated hosts have been well characterized in landfill leachate, such information remains limited for MSW landfills, which are the original source of the resistome. This knowledge gap impedes effective ARG monitoring at the source and poses challenges for public health management. Herein, we investigated the profiles of ARGs, their potential drivers, and associated hosts in refuse samples collected from a large-scale landfill using metagenomic sequencing and quantitative polymerase chain reaction analysis. Our findings revealed that landfills harbor diverse ARGs, with multidrug resistance genes (MDRGs) emerging as the dominant class, accounting for 39.78% of all ARGs detected. Notably, MDRGs exhibited high mobility potential (associated with plasmids, phages, and mobile genetic elements (MGEs)) and were frequently colocated with virulence factors. Pseudomonas, Acinetobacter, and Brevundimonas were identified as key MDRG hosts. Partial least-squares path modeling analysis indicated that MDRG variation was driven by multiple factors (i.e., MGEs, metal resistance genes (MRGs), hosts, and environmental factors). Additionally, metagenome-assembled genomes were found to carry multiple MDRGs. Collectively, these results underscore the role of landfills as critical hotspots for MDRGs.

Soil acidification reduces the abundance and activity of beneficial microorganisms, impairs tea plant growth, and ultimately leads to a decline in tea quality. Maintaining healthy soil is critical for sustainable tea agriculture. However, the interactive effect of biochar and nitrogen fertilizer on the microbial community structure and function in acidic tea plantation soils remains unclear. This study was designed to explore whether the co-application of biochar and fertilizer could enhance soil properties and maintain microbial health in tea plantations. Three treatments were set up through a controlled pot experiment: no fertilizer or biochar application (B₀N₀), fertilizer without biochar (B₀N₁), and biochar with fertilizer (B₁N₁). High-throughput sequencing technology was used to investigate the characteristics of soil microbial communities in tea plantations. Biochar amendment increased soil pH by 0.8 units, organic matter and total nitrogen by 13.5% and 21.4%, and reduced NH₄⁺-N and NO₃⁻-N leaching by 10.8% and 12.9%, respectively. It also modulated microbial community structure, enhanced the abundance of nitrogen-cycling genes (e.g., narB, nirK, nosZ), and influenced nitrogen availability through adsorption. Nitrate was identified as the main factor shaping microbial communities under fertilization. These results highlight the potential of biochar as a sustainable amendment to improve soil health and nitrogen retention in tea cultivation systems. Further field studies are warranted to validate its efficacy in enhancing tea productivity and reducing environmental nitrogen losses under real-world conditions.

Plants possess a complex signaling system that enables them to sense and adapt to various environmental stressors, including abiotic factors like extreme temperatures, drought, salinity, and toxic heavy metals. While the roles of hormones and signaling molecules in plant stress responses are well established, the involvement of neurotransmitters—traditionally linked to animal nervous systems—in plant stress physiology is a relatively underexplored area. Recent findings indicate that neurotransmitters such as gamma-aminobutyric acid, glutamate, serotonin, and dopamine play crucial roles in several physiological processes within plants. They regulate ion channels, adjust stomatal movements, modulate the production of reactive oxygen species, and influence gene expression. Evidence suggests that these neurotransmitters enhance antioxidant defense mechanisms and regulate stress-responsive pathways vital for plant stress tolerance. Additionally, under stressful conditions, neurotransmitters have been shown to impact plant growth, development, and reproductive activities. This review aims to illuminate the emerging understanding of neurotransmitters as key biomediators in plant responses to abiotic stress.

Phosphorus (P) discharge from anthropogenic sources, notably sewage effluent and agricultural runoff, significantly contributes to eutrophication in aquatic environments. Stringent regulations have heightened the need for effective P removal technologies in wastewater treatment processes. This paper provides a comprehensive review of current P removal methods, focusing on both biological and chemical approaches. Biological treatments discussed include enhanced biological P removal in activated sludge systems, biological trickling filters, biofilm reactors, and constructed wetlands. The efficiency of microbial absorption and novel biotechnological integrations, such as the use of microalgae and fungi, are also examined. Chemical treatments reviewed encompass the application of metal salts, advanced oxidation processes such as chlorination, ozonation, and the Fenton reaction, as well as emerging techniques including the Electro-Fenton process and photocatalysis. Analytical methods for P, including spectrophotometric techniques and fractionation analyses, are evaluated to understand the dynamics of P in wastewater. This review critically assesses the strengths and limitations of each method, aiming to identify the most effective and sustainable solutions for P management in wastewater treatment. The integration of innovative strategies and advanced technologies is emphasized as crucial for optimizing P removal and ensuring compliance with environmental regulations.

The fate and transport of non‐steroidal anti‐inflammatory drugs (NSAIDs) in soil are determined by various processes, and the complexity of the system lends itself to the use of computer simulation models to help understand it. This study demonstrated the first attempt to use empirical data from lab incubation and field studies to parameterize and test a process‐based agricultural systems model, Root Zone Water Quality Model 2 (RZWQM2), to simulate the fate and transport of naproxen (NPX), ibuprofen (IBF), and ketoprofen (KTF) in field‐based lysimeters amended with alkaline‐treated biosolids (ATBs). The model calibrated for the soil–water balance module and contaminant transport module was used to predict water seepage through the soil profile in 2017 and 2018 within a 15% error of the field measured data, with model performance statistics such as Nash—Sutcliffe model efficiency (NSE) and R² all greater than 0.70. The overall predicted percent recovery of initial spiked NSAIDs in both soil and water samples, after further calibration of the contaminant transport module, was within the same order of magnitude as the measured data. The model underestimated the percent recovery of initial spiked NSAIDs at the 30‐ to 55‐cm soil depth for all treatments on day 3. The calibrated soil subsurface aerobic half‐lives of NPX and IBF were found to be considerably lower than their laboratory‐measured half‐lives obtained from the incubation study. The overall performance of RZWQM2 in simulating the soil hydrology and behavior of NSAIDs in soil profiles receiving various rates of ATB amendments was satisfactory.