The objective of this study was to assess the effects of a sugarcane bagasse-derived biochar (309 m(2) g(-1); pH 9.3) on herbicide dissipation and ecotoxicity in two contrasting soils (Norwood and Alligator) to identify potential environmental implications. Biochar effects on herbicide dissipation were strongly compound-specific and soil-dependent. Biochar enhanced the dissipation of metolachlor (MET), reducing its half-life from 141 to 78 days in Alligator soil, whereas it inhibited the dissipation of trifluralin (TRI), increasing its persistence, with residual concentrations up to 6-fold higher in amended soils. These responses were linked to herbicide physicochemical properties and their interactions within biochar-soil systems. Ecotoxicity responses were also organism-specific. Biochar-amended soils increased inhibition of Vibrio fischeri (up to similar to 42%), while consistently reducing phytotoxicity to Sorghum saccharatum, with inhibition values falling below the 20% toxicity threshold earlier than in non-amended soils. Soil type influenced the magnitude of ecotoxicological responses, with generally higher inhibition observed in Norwood soil. Overall, biochar altered both herbicide fate and biological effects, revealing a trade-off between reduced phytotoxicity and increased persistence or toxicity in the bacterial bioassay depending on the compound. These findings emphasize the need to consider herbicide properties and soil characteristics when evaluating biochar applications and support the inclusion of multiple bioassays in environmental risk assessment.

Enhancing soil organic carbon (SOC) and aggregate stability is pivotal for maintaining soil health and ensuring agricultural sustainability. However, conventional organic amendments often exhibit suboptimal efficiency in achieving these goals. Hydrochar, synthesized via hydrothermal carbonization (HTC), offers a promising solution by integrating labile and recalcitrant carbon fractions to synergistically address these challenges. However, its mechanisms of action remain not fully understood. In the present study, a microcosmic incubation experiment was conducted to evaluate the short-term impacts of hydrochar on SOC sequestration and soil aggregation in comparison with biochar and straw in a purple soil (Entisol). Hydrochars derived from maize straw (SH), pig manure (PH), and Zanthoxylum stalks (HH) were also compared to assess feedstock-driven variability. The results demonstrated the superior performance of hydrochars, particularly those derived from Zanthoxylum stalks, which significantly increased the mean weight diameter (MWD) by 70–100

This study was conducted to determine how irrigation alters the effects of biochar on soil health parameters in a coarse texture soil for two consecutive growing seasons. Surface soil (0–15 cm) samples from a split-plot randomized block design (main plots, unirrigated and irrigated; subplots, 0 and 11.2 Mg ha− 1 biochar) taken after soybean (Glycine max) harvest in 2022 and 2023 were analyzed for electrical conductivity, pH, labile and total C, inorganic and total N, respiration rate, activities of four extracellular enzymes, and phospholipid fatty acid profiles. Yield was also measured. Neither biochar nor irrigation increased yield. Biochar increased pH and β-glucosidase activity but decreased phosphatase activity. Irrigation reduced organic C, respiration and activities of all enzymes except arylsulfatase. Principle component analysis showed that parameters related to organic C turnover were important without irrigation. Structural equation modeling for respiration rate found small positive effects of phosphatase activity and labile C with irrigation (P < 0.10), but large positive effect of phosphatase without (P < 0.01). An interrelationship of other enzymes and microbial biomass was important to respiration without irrigation, though not with irrigation. The effect of irrigation on soil health parameters in a coarse texture soil for two growing seasons was greater than the effect of biochar.

Sub-Saharan Africa (SSA) faces fertilizer scarcity due to import dependency and high logistics costs. Decentralized green ammonia, powered by local renewable technology, offers a cleaner pathway to improve nitrogen access, but its deployment is constrained by ammonia handling, storage, safety and the need to convert NH3 into agronomically practical and stable products. This review provides an overview on ammonia capture and ammonia-to-fertilizer conversion routes with an emphasis on low-cost, locally producible sorbents and carriers such as, biochar, aluminosilicates (zeolites and bentonites), activated carbon, and agro-industrial residues. In addition, we examine the emerging role of hydrogels and superabsorbent polymer (SAP) systems as moisture-retaining matrices and controlled-release carriers. We propose a decision-oriented framework linking material properties such as, cation exchange capacity (CEC), acidity/functional groups, porosity and pore structure and operating conditions (humidity, pH, and temperature) to capture performance, storage capacity and stability, and nutrient-release behavior under smallholder constraints. We further outline key principles for designing scalable formulation pathways, including reactive granulation and carrier impregnation, to reduce volatilization, improve handling, and enable multi-nutrient products using regionally available inputs. Key research gaps and deployment bottlenecks are identified to guide cleaner and distributed fertilizer manufacturing in SSA.

This study investigated the effects of feedstock type and pyrolysis temperature on the ecotoxicological properties of biochars through standardized bioassays. Ten feedstocks were pyrolyzed at temperatures ranging from 350 to 650 degrees C, and were characterized for elemental composition, PAHs, and physicochemical traits. Bioassays with Vibrio fischeri, Pseudokirchneriella subcapitata, Lepidium sativum, and Sorghum saccharatum were performed to assess ecotoxicity. Increasing pyrolysis temperature enhanced surface area, C:N ratio, ash content, and pH; however, feedstock type was the dominant factor influencing biochar properties and toxicity. Although all biochars complied with international thresholds for contaminants, 28 % induced >= 50 % inhibition in test organisms, underscoring the importance of ecotoxicological evaluation. Biochars derived from cattle manure, poultry litter, and rice straw exhibited the strongest toxicity, largely attributed to salinity stress from high potassium concentrations. In addition, biochars produced at 350 degrees C were generally more toxic, presumably due to the presence of volatile organic compounds. These findings underscore the importance of integrating chemical and biological assessments for safe biochar application in agricultural and environmental systems.

This study determined the optimal conditions for extracting Si from rice husk (RH) for efficient resource utilization of RH and evaluated the adsorption characteristics of methylene blue (MB) by Si-extracted RH (Si-RH). The optimal conditions for extracting silica from RH were mixing 0.6 M NaOH (1:10 ratio) with RH (>2 mm) and reacting at 70 C-degrees for 2 h. The maximum adsorption amount of MB by Si-RH with expanded surface area and reinforced cellulose-hemicellulose-lignin matrix was 99.01 mg/g, which was three times higher than that of RH (34.36 mg/g), and better fit the Langmuir isotherm and Pseudo-second order models. It was found that the adsorption of MB by Si-RH was greatly affected by environmental changes such as reaction time, pH, dosage, and reaction temperature. The surface properties by SEM-EDS and FTIR and the adsorption model equation showed that the adsorption of MB by Si-RH was dominated by complex mechanisms rather than a single mechanism, and these greatly influenced the initial adsorption-desorption process of MB by Si-RH. In continuous adsorption-desorption experiments, Si-RH showed excellent adsorption efficiency for MB. In conclusion, the extraction of silica from RH and utilization of the residue as a dye adsorbent proposed in this study is considered to be the optimal method for realizing zero waste of RH.

Nitrogen (N) fertilizer management in agricultural field affects soil N budget. As N stabilizer, nitrification inhibitor (NI) and urease inhibitor (UI) were widely used to reduce N loss. In this study, a two-year field experiment was conducted to investigate the efficiency of separated and integrated use of dicyandiamide (DCD) and 3,4-dimethyl pyrazole phosphate (DMPP), as well as UI (NBPT) along with N fertilizer UAN on N loss in Louisiana subtropical cornfield (Check, UAN, UAN + DCD, UAN + DMPP, UAN + DMPP×2, UAN + NBPT, and UAN + DCD + NBPT). Specifically, N loss were determined by indicators of nitrous oxide (N2O) gas emission, corn yield, N use efficiency (NUE), and ratio of NH4+ to (NO3− + NO2−). Results show that all N stabilizers reduced the N2O comparing to UAN only, with efficiency order of DMPP×2 > NBPT + DCD > DCD > DMPP > NBPT. In addition, N2O emission showed response to N stabilizers with same the trend in morning and night but significantly (p < 0.05) higher emission in morning than night. More, DMPP, DMPP×2, and NBPT + DCD significantly (p < 0.05) increased NUE. Further, DMPP×2 and DCD + NBPT show significant (p < 0.05) positive correlations with NH4+ while negative correlation with NO3− + NO2− in soil. Overall, combination applications of DCD + NBPT was suggested in Louisiana cornfield with high efficiency on reducing N loss through N2O, improving fertilizer recovery, and reducing the conversion of NH4+-N to NO3−/NO2− -N.

Coastal wetlands store large amounts of soil organic carbon(SOC),and have assumed key roles in mitigating increasing CO2 in the atmosphere.The ongoing debate about SOC stabilization mechanisms stems partly from our incomplete understanding of its com-plex chemical architecture at the molecular scale.Deciphering the molecular composition of soil organic matter is crucial for revealing mechanisms that govern SOC persistence.This study utilized the field sampling data from 2016 and aimed to characterize molecular composition of SOC in typical salt marsh(SM)and freshwater marsh(FM)in Louisiana coastal regions,USA by extending the applica-tion of graph networks with pyrolysis-gas chromatography-mass spectrometry,and then to quantify potential links between SOC persist-ence and molecular diversity and network complexity.The results revealed that SOC predominantly consisted of alkyl compounds(Al-kyl),phenol(Ph),lignin(Lg),and aliphatic compounds,constituting 23.21%and 27.85%,17.84%and 21.55%,16.94%and 15.49%,17.20%and 15.93%of total ion chromatogram(TIC)in SM and FM wetlands,respectively.Molecular diversity in SM was higher than that in FM,while the network graph exhibited greater complexity in FM,featuring 167 and 123 nodes,and 1935 and 1982 edges in the network graphs of SOC from SM and FM,respectively.Correlation analysis confirmed positive relations between molecular diversity indices,network complexity,and abundance of stable carbon isotopes(δ13C).The variance partitioning analysis(VPA)supplied that soil nutrients exerted the most significant control on SOC persistence.Molecular diversity and network complexity,when combined with soil nutrients,could explain 34%of the variances in SOC persistence.

This study investigates the ecotoxicological effects of two contrasting biochars, produced from cattle manure (CMB) and rice husk (RHB), applied to two agricultural soils with divergent properties: a calcareous silt loam (Norwood) and an acidic clay (Alligator). The biochars differed markedly in their physicochemical profiles: CMB exhibited high pH (11), electrical conductivity (12 dS m-1), and K content (89 g kg-1), while RHB showed much greater surface area (174 vs. 1.7 m2 g-1). Ecotoxicity was assessed through four bioassays (Vibrio fischeri, Pseudokirchneriella subcapitata, Sorghum saccharatum, and Lepidium sativum). CMB caused strong toxicity in all aqueous bioassays, while RHB showed no adverse effects. When applied to soils, CMB reduced the toxicity of acidic Alligator soil to P. subcapitata (from 54 % to 16 %) and reclassified its hazard level from class III to I, likely due to aluminum immobilization (Al3+). Conversely, CMB slightly increased toxicity in Norwood soil while RHB improved ecotoxicological profiles in both soils. These results highlight the critical role of soil-biochar interactions in modulating environmental risk. This study links biochar composition and soil properties to bioassay outcomes, offering a practical approach to assess bioavailability-driven toxicity across realistic combinations of biochar and agricultural soils under controlled conditions. These findings underscore the need to align biochar-soil combinations with specific management goals, whether agronomic, environmental, or both.

Plant-derived phenolic compounds could regulate redox reactions due to their antioxidative properties. In this study, soils from coastal wetlands including bare flat (BF), cyperus(Cyperus malaccensis) (CY), reed (Phragmites australis) (RE), and mangrove(Kandelia obovata) (MA) in Minjiang estuary region were selected. Anaerobic microcosm incubation experiments were conducted to investigate the petroleum hydrocarbon (PH) degradation process through denitrification. In addition, effect of plant-derived antioxidants (carotenoids, anthocyanins, flavones, and phenolic acids) on the activity of denitrifying bacteria, enzymes, and genes were studied. The results showed that addition of NO3- significantly (p < 0.05) promoted PH degradation in BF, RE, and CY by 14.1 %-31.7 % while not influenced on PH degradation in MA. Bacteria that could degrade petroleum through denitrification (e.g., Burkholderia and Rhodococcus) showed much higher abundances in CY and RE than in MA. Antioxidants of cover plants showed large varieties with RE containing highest contents of carotenoids while MA containing highest contents of phenolic compounds (anthocyanins, flavones, and phenolic acids). These phenolic antioxidants significantly reduced the activity of NO3- and NO2- reductase and abundances of denitrification genes (nirK) and the inhibition effect was positively correlated to Trolox Equivalent Antioxidant Capacity (TEAC). Overall, our results demonstrate the key regulation role of plant-derived antioxidants in OC degradation in eutrophic wetlands.

Remediation of eutrophic water is a challenging task. Modification of biochar has been demonstrated to enhance the removal ability of contamination of biochar. In this work, magnesium (Mg) and copper (Cu) were incorporated in biochar during preparation to increase the removal of phosphate (P) and inhibit algae bloom. The results showed that Mg-modification significantly (p < 0.05) improved the adsorption of phosphate, and the adsorption capacity was 138.7 mg g−1, and the improvement on P removal was attributed by the formation of MgO which enhanced the sorption affinity on PO43−. In addition, Cu-modification showed significant (p < 0.05) inhibition effect on growth of cyanobacteria as compared to original biochar with biomass decrease of 62

Understanding long-term effects of agricultural management influences on soil organic carbon (SOC) dynamics and aggregate stability is essential for crop production sustainability. In this study, effects of crop rotation, cover crop and nitrogen (N) fertilization on SOC physical and molecular fractions and water-stable aggregate stability were evaluated by characterizing soils of the world’s oldest, century-long (> 120 years) continuous cotton experiment located in the southern USA. Field treatments include: 1) Continuous cotton with no winter legume/no N (CK), 2) Continuous cotton with winter legume (CWL), 3) Corn-cotton rotation with winter legume (CCWL), 4) Corn-cotton rotation with winter legume plus mineral fertilizer N (CCWLN), and 5) Continuous cotton only with mineral N fertilizer (CN). Total organic C (TOC), total nitrogen (TN) as well as acid-hydrolysis C (AHC) and water extractable organic C (WEOC) from both bulk soil and different aggregate fractions were determined. Soil organic matter (SOM) composition was characterized using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results showed that CCWL and CCWLN increased bulk soil TOC, AHC and TN by 150-165%, 300-315%, and 198-223%, respectively, as well as aggregates-associated C by 180-246% over CK. The CWL and CN treatments also increased TOC, AHC, and TN but at a less degree. The CCWL increased macroaggregates (250-2000 µm) by 92% followed by CCWLN by 46%, whereas CWL and CN had only limited effects by 1-7% compared to CK. Moreover, CCWL and CCWLN soil samples had more and diversified compounds of polysaccharides, aliphatic, aromatic, lignin, and phenols followed by CWL, CN and CK samples. Across different treatments, aggregate stability indices, mean weighted diameter (MWD) and geometric mean diameter (GMD), were positively related to TOC and TN (R2=0.57-0.65), N-containing compounds and phenols (R2 = 0.71-0.89) as well as polysaccharides and aliphatics (R2=0.53-0.71). It was concluded that the diversified inputs of SOM composition brought by synergistic interactions between corn rotation and winter legume inclusion were mainly responsible for the observed TOC accumulation and aggregate formation and stability in these subtropical cotton production systems.

Abstract Bermudagrass is a summer forage crop with high nitrogen (N) demand. Introducing winter cover crops may sustain bermudagrass yields with less fertilizer, reducing environmental N losses. Field trials and lab incubation were carried out to evaluate the effects of white clover (Trifolium repens L.) and ryegrass (Lolium multiflorum) as winter cover crops on soil N losses through runoff and nitrous oxide (N2O) emissions in a subtropical bermudagrass (Cynodon dactylon L.) pasture field. The 2‐year field experiment included five treatments: (1) no winter cover and N fertilization as a control (CLT), (2) white clover without N fertilization (WC) (where WC represents white clover), (3) white clover mixed with ryegrass without N fertilization (WCR), (4) white clover with half‐rate N at 112 kg N ha−1 year−1 (WC112N), and (5) no cover crop with full‐rate N 224 kg N ha−1 year−1 (224N). Results showed that without N fertilization, WC increased bermudagrass biomass by 38% compared to CLT, while WCR had a similar bermudagrass biomass yield to CLT. WC112N produced comparable bermudagrass biomass as 224N as well as reduced NH4+ and NO3− runoff loss by 30%–35% and 11%–24%, respectively, compared than 224N, due to decreased runoff volume. There was no difference in N2O emissions between 224N and WC112N. Laboratory incubation of white clover residue‐amended soil showed that nitrification inhibitors dicyandiamide and 3,4‐dimethylpyrazole phosphate lowered N2O emission significantly, with a maximum reduction of 77%–91%, while urease inhibitor N‐(n‐butyl) thiophosphoric triamide had no effect. Overall, clover incorporation during the winter season helps in developing a low‐N‐input pasture production system, and nitrification inhibitors could be applied to mitigate associated N2O losses from clover residue decomposition.

Conventional delayed‐flood rice ( Oryza sativa L.; DFR) cultivation in United States faces increasing challenges such as nutrient losses, water scarcity, and greenhouse gas emissions. Alternative furrow‐irrigated rice (FIR) cultivation is gaining interest for its water use efficiency and production flexibility. Despite FIR's growing adoption, its impacts on soil biological functioning and nutrient cycling remain poorly understood, limiting the ability to optimize management practices for this emerging system. Understanding these impacts is crucial as soil health directly influences nutrient availability, crop productivity, and long‐term sustainability. This study aimed to compare soil enzyme activities and other health indicators between DFR and FIR systems. Soil samples were collected from Louisiana DFR and FIR field experiments established in 2020 and 2021 and analyzed for β‐glucosidase (BG), β‐glucosaminidase (NAG), phosphomonoesterase (PME), arylsulfatase (AST), permanganate oxidizable carbon (POXC), respiration (CO 2 ‐burst), and alkali‐hydrolysable nitrogen (AHN). Principal component analysis (PCA) revealed distinct separations between the DFR and FIR systems in different sites. The results showed that the FIR system significantly ( p < 0.05) increased NAG by 35%–57% and AST by 35%–113% activities at both sites as well as BG by 35% and PME by 92% at one of the two site‐years over the DFR system, indicating improved nutrient cycling. The FIR also had significantly ( p < 0.05) higher CO 2 ‐burst by 21%–33% and POXC by 44% at one of the two sites than the DFR. Rice grain yields were significantly and positively related to BG ( R 2 = 0.28, p < 0.05 ) and PME ( R 2 = 0.18, p < 0.05 ) in the FIR system across site‐years but not in the DFR system, reflecting different sensitivities of these enzymes to the two rice cultivations. This study provides insights into understanding the difference in nutrient cycling between the two rice production systems.

The objectives of this study were to produce biochars using sulfur-rich acidified lignin discharged from a biorefinery process and to evaluate their physicochemical properties and Pb adsorption capacity. As the pyrolysis temperature increased, the lignin acidified by the desulfurization process was converted to neutralized biochar (LBC), which exhibited high carbon content and stability. The carbon content of biochar manufactured at a pyrolysis temperature of 600 degrees C or higher was over 90 % and showed no significant difference, and their surface structures were found to be different, as revealed through XRD and FTIR analyses. The adsorption capacity of Pb by LBC increased with increasing pyrolysis temperature, and their adsorption capacity was well described by the pseudo-second-order model and the Langmuir isotherm adsorption model. In particular, the internal diffusion effect on the adsorption capacity of Pb was greater for LBC900 than for LBC600. In complex heavy metal solutions, LBC selectively exhibited high affinity for Pb, while the adsorption capacity of other metals was significantly reduced. The adsorption mechanism of Pb by LBC was verified through various analytical methods, and these results demonstrated that the adsorption of Pb by LBC was influenced by functional groups existing on the surface and inside of LBC and by some cation exchange.

Phthalic acid esters (PAEs) showed high environmental risk due to the widely existence and toxicity. Microbial-excreted extracellular polymeric substances (EPS) showed potential of degrading organic compounds. In this study, the degradation ability and the mechanisms of EPS from two bacteria (PAEs degrader Gordonia sihwensis; electrochemically active strain Shewanella oneidensis MR-1) were investigated. Results showed that EPS of the two bacteria had different composition of C-type cytochromes, flavins, catalase, and α-glucosidase. The removal of dibutyl phthalate (DBP) by total EPS were 68% of G. sihwensis and 72% for S. oneidensis. For both bacteria, the degradation rates k of EPS were as TB-EPS > LB-EPS > S-EPS. The degradation mechanisms of EPS from the two bacteria showed difference with electrochemical active components mediated electron transmission for S. oneidensis MR-1 and enzymes catalysis for G. sihwensis. Results of this study illustrated the variation of the contribution of active components of EPS to degradation.

AbstractConservation agriculture (CA) aims to sustain agricultural production, soil, and environmental health in agroecosystems and has been promoted throughout the United States. The adoption of CA in cotton (Gossypium hirsutum) systems provides both agronomic and environmental benefits. Yet, there is limited information on the long‐term effects of CA practices on crop yield and adaptation strategies. An integrated CA system, that is, cover crops with no‐tillage (NT) instead of conventional agriculture, was implemented in the long‐term field experiments and assessed with an integrated biogeochemical model. Using the denitrification–decomposition model, this study estimated the effects of four different cover crops, for example, native grass (NG), hairy vetch (Vicia villosa), winter wheat (Triticum aestivum L.), and crimson clover (Trifolium incarnatum), on cotton yield under four different nitrogen (N) levels (e.g., 0, 50, 100, and 150 kg N/ha) and estimated responses on carbon (C) sequestration, and ecosystem functionality over a 10‐year study. The NT‐NG 50 N was used as a calibration dataset to accurately estimate the cotton lint yield with a normalized root mean square error (NRMSE) of 21% and model efficiency of 0.3. The calibration data validated the effects of hairy vetch, winter wheat, and crimson clover under the NT‐50 N with NRMSE of 24%, 21%, and 25%, respectively. According to the scenario analysis, the 50 kg N/ha application with a single‐irrigation event (10‐cm depth) was most beneficial for maximizing the cotton yield with cover crop incorporation at the NT system over the long term. The effects of increasing cover crop biomass (i.e., double seed rate) on C content, regardless of N application rates, varied based on the relationship between the main and cover crop species. Besides, the furrow plow tillage system provided efficient C sequestration. The proposed approach stands to provide agricultural and environmental sustainability with the implementation of cover crop or crop residue incorporation instead of increased N application, seed rates, and irrigation events under NT practices.

Loss of phosphorus in seepage may contribute to eutrophication of downstream water bodies. This study examined the potential use of pedogenic ironstone and untreated red mud (bauxite refining residue) as P sorbents in a permeable reactive barrier (PRB) to mitigate such loss. Effects of ironstone and red mud on P sorption (batch), transport (columns), saturated hydraulic conductivity (KS), and growth of common bermudagrass (Cynodon dactylon; greenhouse) were examined. Both materials had sorption maxima of ∼30 mmol P kg-1 or about five times that of a P-enriched sandy soil; however, sorption by red mud greatly increased with decreasing pH. Transport of P through columns of ironstone and red mud (diluted with nonreactive sand) was similar and slower compared to soil + sand. However, when red mud was mixed with soil, increased sorption at lower pH resulted in greater P retention compared to ironstone + soil (76% vs. 13%). Although addition of ironstone to soil up to 20% did not reduce KS, red mud at even 5% did. Soil amendment with red mud increased bermudagrass growth and P uptake. Given long-term neutralization of red mud in an acidic soil and increased P sorption, it may be suitable in a PRB if incorporated at a low rate and/or co-incorporated with a coarser material.

Metal-biochar composites with varying Fe/Mn ratios were synthesized for activating peroxymonosulfate (PMS) oxidative degradation of azo dye Orange G (OG) were investigated. The 1Fe2Mn-BC composite based on 1:2 molar ratio impregnation of Fe/Mn salt concentrations of efficient sugarcane harvest residue showed the best catalytic performance under aqueous pH 3-10 and had the least impacts from coexistence of inorganic anions and humic acids. The OG degradation by 1Fe2Mn-BC/PMS system optimized at catalyst:oxidant:pollutant ratio of 1:1.25:0.5 on g/L basis was found to follow pseudo-first-order kinetic and achieved 100 % degradation efficiency within 30 min. Apparent activation energy for OG degradation by 1Fe2Mn-BC/PMS was 16.91 kJ mol- 1, and increasing reaction temperature from 293 to 313 K enhanced degradation rate constant by 49 %. Electron paramagnetic resonance (EPR) and radical quenching experiments revealed dominant non-radical 1O2 and radical O2 center dot- pathways in the OG oxidation removal by the 1Fe2Mn-BC/PMS system, although SO4 center dot- and center dot OH radicals also participated. XPS spectra of 1Fe2Mn-BC before and after OG degradation indicated dominant surface composition of Fe(III) and Mn(II) valence states over other FeMn-biochar composites. The novel optimized one-step pyrolysis Fe/Mn bimetal biochar composite provides an efficient PMS activation for advanced oxidation process (AOP) treating of azo dyes in wastewater decontamination.

Amidst intensifying global agricultural water demand, optimizing management practices and understanding the role of soil amendments, particularly biochar (BC), in modulating soil water dynamics are critical. Here, we review the potential impacts of BC on soil water dynamics, elucidate mechanistic underpinnings, and identify critical research gaps and prospective avenues. In general, BC modifies soil structure, hydraulic properties, surface albedo, and heat fluxes, which influence soil water storage, energy balance, and irrigation paradigms. Depending on soil texture and BC properties, BC demonstrates a greater reduction in bulk density and saturated hydraulic conductivity in coarse-textured soils compared to fine-textured soils. BC application generally increases water holding capacity (WHC) while exhibiting no consistent impact on soil water infiltration. Increased WHC of soils results from increased porosity, surface area, and soil aggregation. Increased porosity arises from a confluence of factors, encompassing new pores formation, reorganization of pores, increased soil aggregation, dilution effects of BC, reduced soil compaction, and biotic interactions, including increased population of burrowing invertebrates. BC tends to increase plant-available water in coarser soils, attributed to its hydrophilic nature, augmented specific surface area, and enhanced overall porosity. However, BC may induce soil water repellency, contingent upon variables such as feedstock composition, pyrolysis temperature, and specific soil attributes. While BC exhibits transformative potential in enhancing soil hydraulic properties, scalability concerns and economic viability pose challenges to its widespread agricultural application. Overall, BC offers promising avenues for sustainable water management. However, it is imperative to explore large-scale applications and conduct long-term field studies across different management, climate, and soil types to fully understand how different types of BC impact soil water dynamics.