Green and facile fabrication of multifunctional cellulose nanocrystal and carvacrol together reinforced chitosan bio-nanocomposite coatings for fruit preservation.

The continuous development of sustainable food-active packaging materials and practices with high performance is a response to the increasing challenges posed by microbial food safety and environmental contamination. In this study, a multifunctional bio-nanocomposite composed primarily of chitosan, cellulose nanomaterials and carvacrol was proposed as a conformal coating for fruit preservation. The coating exhibits excellent antioxidant and antibacterial activities owing to the incorporation of the carvacrol. The inhibition rate of the coating on E. coli and S. aureus is enhanced by 57.13 % and 62.18 %, respectively. And its antioxidant activities is also improved by 77.45 %. In addition, the oxygen permeability (OP) and water vapor permeability (WVP) of this CS/CNC coating are significantly lowered by 67 % and 46 %, respectively, comparing with the CS coating. The coating exhibited excellent biosafety and cytocompatibility because of over 90 % of the HepG2 cells remained alive in each concentration of the coating after 24 h incubation. Additionally, the efficacy of the coating in prolonging the freshness and visual appeal of perishable fruits is substantiated by the experiment involving two fruit specimens. Furthermore, the coating's ease of production, ingestibility, washability, and utilization of cost-effective and easily accessible biomaterials, including renewable waste materials, indicate its potential as a viable economic substitute for commercially accessible fruit coatings.

Removal of contaminants present in water and wastewater by cyclodextrin-based adsorbents: A bibliometric review from 1993 to 2022.

Cyclodextrin (CD), a cyclic oligosaccharide from enzymatic starch breakdown, plays a crucial role in pharmaceuticals, food, agriculture, textiles, biotechnology, chemicals, and environmental applications, including water and wastewater treatment. In this study, a statistical analysis was performed using VOSviewer and Citespace to scrutinize 2038 articles published from 1993 to 2022. The investigation unveiled a notable upsurge in pertinent articles and citation counts, with China and USA contributing the highest publication volumes. The prevailing research focus predominantly revolves around the application of CD-based materials used as adsorbents to remove conventional contaminants such as dyes and metals. The CD chemistry allows the construction of materials with various architectures, including cross-linked, grafted, hybrid or supported systems. The main adsorbents are cross-linked CD polymers, including nanosponges, fibres and hybrid composites. Additionally, research efforts are actually concentrated on the synthesis of CD-based membranes, CD@graphene oxide, and CD@TiO2. These materials are proposed as adsorbents to remove emerging pollutants. By employing bibliometric analysis, this study delivers a comprehensive retrospective review and synthesis of research concerning CD-based adsorbents for the removal of contaminants from wastewater, thereby offering valuable insights for future large-scale application of CD-based adsorption materials.

Enhancing the bifunctional oxygen reduction and evolution activity of CoNC by introducing a trace amount of Fe.

The potential application of zinc air batteries to tackle the energy shortage and environmental crisis has proposed new requirements of bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Utilizing the special spatial structure of zeolitic imidazolate framework-67 (ZIF-67) as an ideal research platform, the effect of a trace amount of Fe on the composition and structure of as-obtained Fe-CoNC catalysts was investigated. It was revealed that, due to the increased exposed pore structure and metal species located at the near surface, the active sites for the ORR/OER on Fe-CoNC are highly exposed, greatly boosting the activity to the reduction and evolution of oxygen in alkaline media. ZABs with Fe-CoNC have the highest maximum power density of 200 mW cm-2 when operated at current densities as high as 328 mA cm-2, better than not only Fe-free CoNC, but also precious metal-based references with the same catalyst loading.

Reduced colloidal phosphorus release from paddy soils: A synergistic effect of micro-/nano-sized biochars and intermittent anoxic condition.

Colloidal phosphorus (CP) has high mobility and great loss risk; their biogeochemical processes are influenced by agricultural management such as redox oscillation and biochar-amendment application. This study monitored CP concentration in pore-water, soil P species and P adsorption capacity, to investigate CP release from paddy soils as affected by the interactive effects of oxygen status (continuous anoxic/oxic for 12 days, CA/CO; intermittent anoxic for 2, 4, 6, 8, 10 days during the 12-day cycle, IA2-10) and management (soil only, CK; bulk/micro/nano-sized biochar with various properties: SBBulk, SBMicro, and SBNano). Compared to the control (0.25-0.84 mg L-1, CK-CA), the single intermittent anoxic treatment (CK-IA) reduced CP concentrations by 45 %, due to the rise of Eh and pH and the decline of the degree of P saturation along with the increased soil Fe/Al-P and organic-P. Longer anoxic duration under the CK-IA reduced CP release, probably donated from massive production of redox-stable amorphous Fe/Al-bound P. The single biochar treatment (SB-CA: SBBulk-CA > SBMicro-CA > SBNano-CA) decreased CP release by 37 % as compared to the CK-CA, ascribed to the increased soil pH, Eh, and P adsorption capacity. The combined treatment (SB-IA: SBBulk-IA2 > SBNano-IA10) synergistically reduced CP release by 68 % in comparison with the CK-CA, due to the increase of adsorption through interactions of soil Fe/Al/Ca- and organic-P. Therefore, nano-sized biochar and long intermittent anoxic duration are recommended for reducing CP release from paddy soils.

Transparent chitosan/hexagonal boron nitride nanosheets composite films with enhanced UV shielding and gas barrier properties.

It is of great significance to develop natural renewable polymer materials for different applications. Herein, the nano-sized hexagonal boron nitride nanosheets (hBNNSs) were facilely exfoliated through liquid-nitrogen, microwave, and ultrasonication treatments, and novel chitosan/hBNNSs (CS/hBNNSs) films were fabricated via solution casting. The obtained transparent CS/hBNNSs films demonstrated outstanding UV shielding ability with 98.51 % UV-A and 96.40 % UV-B lights being resisted. Compared to those properties of CS film, the oxygen permeability (OP) and carbon dioxide permeability (CO2P) of CS/hBNNSs films are significantly lowered by 96.35 % and 94.06 %, respectively, which are much better than CS/graphene oxide or other CS nanocomposite films. Moreover, the addition of hBNNSs in CS films also obviously improves their water vapor barrier ability, thermostability, mechanical properties, and antibacterial activity. The CS/hBNNSs films and the strategy developed in this work prove their great prospect in producing high-performance packaging films with desirable excellent UV shielding and oxygen barrier qualities.

Biodegradable mulch films improve yield of winter potatoes through effects on soil properties and nutrients.

Biodegradable mulch films are recognized as a promising substitute of polyethylene (PE) films to alleviate the "white pollution". Biodegradable mulch films with optimum degradation rates increase crop yield even compared to PE films. However, the mechanisms underlying this yield-increasing effect remains elusive. In this study, three biodegradable film treatments (BFM1, BFM2 and BFM3) and one PE film treatment (PFM) were used to evaluate their effects on soil and winter potatoes, and a partial least squares path model (PLS-PM) was constructed to investigate their relationships. The degradation rates of films under different treatments were ranked as BFM3 > BFM2 >BFM1 > PFM, and presented distinctive effects on soil properties and nutrients, structure of soil bacterial community, and yield traits of winter potatoes. The PLS-PM showed that mulch treatments affected potato yield through effects on soil properties (soil water and temperature) and soil nutrients (TOC, DOC, TN and NO3--N). The disintegration of the biodegradable films decreased soil water content and temperature, and reduced the loss of soil nutrients in the topsoil at the later growth stage of winter potatoes compared to PE films. Additionally, the elevated content of soil TN and NO3--N under treatment BFM1 may play a key role in its yield-increasing effect on potatoes compared to treatments PFM and BFM2. Thus, biodegradable mulch films with proper degradation rates regulate soil TN and NO3--N through their effects on soil water and temperature, and subsequently improve the yield of winter potatoes compared to PE mulch films.

Unveiling the drives behind tetracycline adsorption capacity with biochar through machine learning.

This study aimed to develop a robust predictive model for tetracycline (TC) adsorption onto biochar (BC) by employing machine learning techniques to investigate the underlying driving factors. Four machine learning algorithms, namely Random Forest (RF), Gradient Boosting Decision Tree (GBDT), eXtreme Gradient Boosting (XGBoost) and Artificial Neural Networks (ANN), were used to model the adsorption of TC on BC using the data from 295 adsorption experiments. The analysis revealed that the RF model had the highest predictive accuracy (R2 = 0.9625) compared to ANN (R2 = 0.9410), GBDT (R2 = 0.9152), and XGBoost (R2 = 0.9592) models. This study revealed that BC with a specific surface area (S (BET)) exceeding 380 cm3·g-1 and particle sizes ranging between 2.5 and 14.0 nm displayed the greatest efficiency in TC adsorption. The TC-to-BC ratio was identified as the most influential factor affecting adsorption efficiency, with a weight of 0.595. The concentration gradient between the adsorbate and adsorbent was demonstrated to be the principal driving force behind TC adsorption by BC. A predictive model was successfully developed to estimate the sorption performance of various types of BC for TC based on their properties, thereby facilitating the selection of appropriate BC for TC wastewater treatment.

Impact of plastic film mulching on microplastic in farmland soils in Guangdong province, China.

Plastic mulch film is often believed to be a significant contributor to microplastic pollution in farmland soil, however, its direct impact in areas with high human activities remains unclear due to the presence of multiple pollution sources. This study aims to address this knowledge gap by investigating the impact of plastic film mulching on microplastic pollution in farmland soils in Guangdong province, China's largest economic province. The macroplastic residues in soils were investigated in 64 agricultural sites, and the microplastics were analyzed in typical plastic film mulched and nearby non-mulched farmland soils. The average concentration of macroplastic residues was 35.7 kg/ha and displayed a positive correlation with mulch film usage intensity. Contrarily, no significant correlation was found between macroplastic residues and microplastics, which exhibited an average abundance of 22,675 particles/kg soil. The pollution load index (PLI) model indicated that the microplastic pollution level was category I and comparatively higher in mulched farmland soils. Interestingly, polyethylene accounted for only 2.7% of the microplastics, while polyurethane was found to be the most abundant microplastic. According to the polymer hazard index (PHI) model, polyethylene posed a lower environmental risk than polyurethane in both mulched and non-mulched soils. These findings suggest that multiple sources other than plastic film mulching primarily contribute to microplastic pollution in farmland soils. This study enhances our understanding of microplastic sources and accumulation in farmland soils, offering crucial information on potential risks to the agroecosystem.

Biochar-coupled organic fertilizer reduced soil water-dispersible colloidal phosphorus contents in agricultural fields.

Soil water-dispersible colloidal phosphorus (WCP) presents high mobility, however, the regulatory effect of biochar-coupled organic fertilizer is rarely known, especially under different cropping patterns. This study investigated the P adsorption, soil aggregate stability, and WCP in three paddy and three vegetable fields. These soils were amended with different fertilizers (chemical fertilizer, CF; substitution of solid-sheep manure or liquid-biogas slurry organic fertilizer, SOF/LOF; substitution of biochar-coupled organic fertilizers, BSOF/BLOF). Results presented that the LOF averagely increased the WCP contents by 50.2% across the sites, but the SOF and BSOF/BLOF averagely decreased their contents by 38.5% and 50.7% in comparison with the CF. The WCP decline in the BSOF/BLOF-amended soils was mainly attributed to the intensive P adsorption capacity and soil aggregate stability. The BSOF/BLOF increased the amorphous Fe and Al contents in the fields in comparison with the CF, which improved the adsorption capacity of soil particles, further improving the maximum absorbed P (Qmax) and reducing the dissolved organic matter (DOC), leading to the improvement of > 2 mm water-stable aggregate (WSA>2mm) and subsequent WCP decrease. This was proved by the remarkable negative associations between the WCP and Qmax (R2 = 0.78, p < 0.01) and WSA>2mm (R2 = 0.74, p < 0.01). This study manifests that biochar-coupled organic fertilizer could effectively reduce soil WCP content via the improvement of P adsorption and aggregate stability.

Improved phosphorus availability and reduced degree of phosphorus saturation by biochar-blended organic fertilizer addition to agricultural field soils.

Phosphorus (P) availability and loss risk are linked to P species; however, their alternations in the soil amended with biochar-blended organic fertilizer is not well known, particularly under contrasting soil properties and land management. In this study, the variance of soil P species extracted by sequential chemical extraction (SCE) and 31P NMR techniques, as well as the degree of P saturation (DPS), were investigated throughout three paddy and three vegetable fields. These fields were amended with three different fertilizers at the same P application rate: chemical fertilizer (CF), organic fertilizer substitution (sheep manure/biogas slurry, SM/BS), and biochar-blended organic fertilizer substitution (BSM/BBS). Results showed that the BSM/BBS and SM increased the total P contents by 7.5% and 5.9% (TP) and available P contents by 30.1% and 19.2% (AP), but decreased the DPS values by 19.4% and 11.7%, compared to the CF treatment. Yet, the BS decreased the TP and AP contents but increased the DPS values across the experimental sites. In the BSM/BBS amended soils, high AP contents were due to the increased inorganic P (NaHCO3-Pi), while the increased organic P (monoester and DNA) induced low DPS values and reduced soil P loss risk. Our study highlights that biochar-blended organic fertilizer is an effective agronomic way for improving P availability and decreasing P loss risk via the alteration of soil P species.

Biochar-blended manure modified by polyacrylamide to reduce soil colloidal phosphorus leaching loss.

Combined application of biochar and organic fertilizer improves soil structure and crop yield but may lead to increased loss of phosphorus (P). To reduce the P loss risk in this case, rice straw biochar (BC) and sheep manure (SM) were modified using polyacrylamide (PAM). The effects of using organic amendments (BC, SM, and PAM-modified organic mixtures) and no amendments (CK) on soil total and colloidal P leaching loss from paddy soils were evaluated through soil column leaching experiments. The soil leachate volume was increased by 8.91% with BC treatment and reduced by 15.3% with SM treatment. The total P leaching loss (973.9 µg kg-1) from the BC-treated soil was higher than that from other treatments (541.4-963.5 µg kg-1). However, there was much more colloidal P loss (480.0 µg kg-1) from SM treatment. The optimal conditions for the preparation of BC and SM modified using polyacrylamide (PSB) for reducing P leaching loss were SM/BC = 4:1, 1% PAM, and 100 °C. Molybdate-unreactive P accounts for 58.61-86.89% of the colloidal P in the soil leachate with organic amendments. PSB reduced colloidal P loss (particularly in 10-220 nm range) by ~ 50% compared with BC and SM treatments. The colloidal P concentration in the leaching solutions was significantly correlated with TOC and susceptible to Fe and Al concentrations. Using PAM-modified mixture instead of manure and biochar as a soil amendment can effectively control P leaching from fields.

Nano and fine colloids suspended in the soil solution regulate phosphorus desorption and lability in organic fertiliser-amended soils.

Mobile colloids impact phosphorus (P) binding and transport in agroecosystems. However, their relationship to P-lability and their relative importance to P-bioavailability is unclear. In soils amended with organic fertilisers, we investigated the effects of nano (NC; 1-20 nm), fine (FC; 20-220 nm), and medium (MC; 220-450 nm) colloids suspended in soil solution on soil P-desorption and lability. The underlying hypothesis is that mobile colloids of different sizes, i.e., NC, FC, and MC, may contribute differently to P-lability in soils enriched with organic fertiliser. NC- and FC-bound Pcoll were positively correlated with P-lability parameters from diffusive gradient in thin films (DGTA-labile P concentration, r ≥ 0.88; and DGTA-effective P concentration, r ≥ 0.87). The corresponding relations with MC-bound Pcoll are weaker (r values of 0.50 and 0.51). NC- and FC-bound Pcoll were also strongly correlated with soil P-resupply (r ≥ 0.64) and desorption (r ≥ 0.79) parameters during DGTA deployment, and the mobility of these colloids was corroborated by electron microscopy of DGTA gels. MC-bound Pcoll was negatively correlated with the solid-to-solution distribution coefficient (r = -0.42), indicating this fraction is unlikely to be the source of P-release from the solid phase after P-depletion from the soil solution. We conclude that NC and FC mainly contribute to regulating soil desorbable-P supply to the soil solution in the DGTA depletion zone (in vitro proxy for plant rhizosphere), and consequently may act as critical conditioners of P-bioavailability, whereas MC tends to form complexes that lead to P-occlusion rather than lability.

Biochar reduces colloidal phosphorus in soil aggregates: The role of microbial communities.

Colloidal phosphorus (Pcoll) in paddy soils can pose a serious threat to the water environment. Biochar amendment not only directly absorb Pcoll to reduce the runoff loss, but also create hotspots for microbial communities which simultaneously affects soil Pcoll. However, despite the crucial role of microorganisms, it remains elusive regarding how biochar and its feedstock types affect the relationships of soil microbial communities and Pcoll in soil matrix (such as at soil aggregate level). To address the knowledge gap, we explored the (in)direct effects of biochar on the soil Pcoll in physically separated fractions including micro- (53-250 µm) and macroaggregates (250-2000 µm). Results showed that straw and manure biochars decreased the soil Pcoll content by 55.2-56.7% in microaggregates and 41.2-48.4% in macroaggregates after 120 days of incubation, compared to the respective control. The fungal communities showed a significantly correlation (0.34, p < 0.05) with Pcoll content in the macroaggregates, whereas the bacterial communities were extremely significantly correlated (0.66, p < 0.001) with Pcoll content in the microaggregates. Furthermore, the partial least squares path model analysis indicated that biochar amendments directly increased Pcoll content (0.76 and 0.61) in micro- and macroaggregates, but the reduced Pcoll content by biochar was mainly derived from indirect effects, such as changed soil biological characteristics carbon (C)/P (-0.69), microbial biomass C (-0.63), microbial biomass P (-0.68), keystone taxa Proteobacteria (-0.63), and Ascomycota (-0.59), particularly for the macroaggregates. This study highlights that to some extent, biochar addition can reduce soil Pcoll content by affecting microbial communities (some keystone taxa), and soil biological characteristics at soil aggregate level.

Intelligent temperature-pH dual responsive nanocellulose hydrogels and the application of drug release towards 5-fluorouracil.

As the typical bio-macromolecules, cellulose and its derivates are widely studied due to the fact that they are green and renewable resources in nature. In this work, intelligent temperature-pH sensitive nanohydrogels consisting of nanocellulose, thermal responsive monomer (N-isopropylacrylamide, NIPAM), and pH responsive monomer (acrylic acid, AA; acrylamide, AM) were prepared [NFC-g-(AA/AM)]-g-NIPAM, the [NFC-g-(AA/AM)]-g-NIPAM was characterized by FTIR, scanning electron microscope (SEM), thermogravimetric analysis (TGA) and automatic gas adsorption analysis (BET). The results showed that the copolymerization of AA, AM and NIPAM were carried out successfully. The specific surface area, total pore volume, average pore diameter and thermal stability of the modified nano-cellulose were increased. In addition, the as-prepared nanohydrogels with 5-fluorouracil (5-FU) released more 5-FU at 40 °C and acidic condition compared to the room temperature and neutral pH, showing the characteristics of the temperature-PH dual response functionalization. The [NFC-g-(AA/AM)]-g-NIPAM have been proved to be the promising drug release nanohydrogels towards 5-FU, and the valuable findings might provide an idea for maximizing the potential of the nanocellulose-based nanohydrogels for the application of environmental pollution control.

Effects of biochar and organic-inorganic fertilizer on pomelo orchard soil properties, enzymes activities, and microbial community structure.

Fertilizer management can influence soil microbes, soil properties, enzymatic activities, abundance and community structure. However, information on the effects of biochar in combination with organic-inorganic fertilizer after 3 years under pomelo orchard on soil bacterial abundance, soil properties and enzyme activities are not clear. Therefore, we conducted a field experiment with seven treatments, i.e., (1) Ck (control), (2) T1 (2 kg biochar plant-1), (3) T2 (4 kg biochar plant-1), (4) T3 (2 kg organic-inorganic mixed fertilizer plant-1), (5) T4 (4 kg biochar + 1.7 kg organic-inorganic mixed fertilizer plant-1), (6) T5 (4 kg biochar + 1.4 kg organic-inorganic mixed fertilizer plant-1), and (7) T6 (4 kg biochar + 1.1 kg organic-inorganic mixed fertilizer plant-1). The soil microbial communities were characterized using high-throughput sequencing of 16S and internal transcribed spacer (ITS) ribosomal RNA gene amplicons. The results showed that biochar combined with organic-organic fertilizer significantly improved soil properties (pH, alkali hydrolysable nitrogen, available phosphorus, available potassium, and available magnesium) and soil enzymatic activities [urease, dehydrogenase (DHO), invertase and nitrate reductase (NR) activities]. Furthermore, soil bacterial relative abundance was higher in biochar and organic-inorganic treatments as compared to control plots and the most abundant phyla were Acidobacteria (40%), Proteobacteria (21%), Chloroflexi (17%), Planctomycetes (8%), Bacteroidetes (4%), Verrucomicrobia (2%), and Gemmatimonadetes (1%) among others. Among the treatments, Acidothermus, Acidibacter, Candidatus Solibacter and F473 bacterial genera were highest in combined biochar and organic-inorganic treatments. The lowest bacterial abundance and bacterial compositions were recorded in control plots. The correlation analysis showed that soil attributes, including soil enzymes, were positively correlated with Chloroflexi, Planctomycetes, verrucomicrobia, GAL15 and WPS-2 bacterial abundance. This study demonstrated that biochar with organic-inorganic fertilizer improves soil nutrients, enzymatic activities and bacterial abundance.

Qualitative and quantitative investigation on adsorption mechanisms of Cd(II) on modified biochar derived from co-pyrolysis of straw and sodium phytate.

Developing effective modification methods and obtaining a comprehensive understanding of adsorption mechanisms are essential for the practical application of biochars for the removal of heavy metals from solutions. In this study, rice straw was impregnated with sodium phytate and pyrolyzed at 350 °C, 450 °C, and 550 °C to synthesize modified biochars (i.e., MBC350, MBC450, and MBC550). The Cd(II) adsorption capacities and contributions of different mechanisms, including the effects of biochar-derived dissolved organic matter (BDOM), were investigated using batch sorption experiments and characterization analyses. The modification of sodium phytate promoted the pyrolysis of biomass, thereby increasing the BDOM content and aromatic structures at low and high pyrolysis temperatures, respectively. Moreover, the modification also increased the exchangeable Na+ and carbonate contents in the modified biochars. Compared with the raw biochars, the Cd(II) adsorption capacities of modified biochars increased by 3.3-4.3 times, and MBC550 had the highest Cd(II) adsorption capacity (126.5 mg/g), of which precipitation with minerals and interaction with π-electrons contributed 41.7% and 45.8%, respectively. However, at a lower pyrolysis temperature, the Cd(II) adsorption attributed to ion exchange and co-deposition with BDOM significantly increased, especially on MBC350 (33.9 and 12.6 mg/g, respectively). These results indicate that modification by sodium phytate effectively enhanced various adsorption mechanisms, thereby increasing the Cd(II) adsorption capacity. In addition, the contribution of co-deposition with BDOM to adsorption was unneglectable for the biochars pyrolyzed at low temperatures.

Pteris vittata plantation decrease colloidal phosphorus contents by reducing degree of phosphorus saturation in manure amended soils.

The agricultural use of manure fertilizer increases the phosphorus (P) saturation of soils and the risk of colloidal P (Pcoll) release to aquatic ecosystems. Two experiments were conducted to identify whether Pteris vittata plantation can decrease Pcoll contents in two soils (Cambisol and Anthrosol) amended with various manure P rates (0, 10, 25, and 50 mg P kg-1 of soil). The total Pcoll contents in manured soil without P. vittata were 1.14-3.37 mg kg-1 (Cambisol), and 0.01-2.83 mg kg-1 (Anthrosol) across manure-P rates. The corresponding values with P. vittata were 0.97-2.33 mg kg-1 (Cambisol) and 0.005-1.6 mg kg-1 (Anthrosol). Experimentally determined colloidal minerals (Fe, Al, Ca), colloidal total organic carbon, Mehlich-3 nutrients (Fe, Al, and Ca), and the degree of P saturation were good predictors of Pcoll concentrations in both soils with and without P. vittata plantation. In unplanted soils, P adsorption decreased and the degree of P saturation increased which released more Pcoll. However, P. vittata plantation decreased the Pcoll release and P loss risk due to the increase of P adsorption and reduced DPS in both soils. The P fractions (NaOH, NH4F, and HCl-P) contributed to increase the P pool in planted soils which enhanced the bioavailability of Pcoll and increased the P. vittata biomass. It suggested that P. vittata plantation was an effective approach to reduce Pcoll release from manure amended soils.

Green Production of Biodegradable Mulch Films for Effective Weed Control.

Biodegradable mulch films are supposed to be a prospective substitute for poly(ethylene)-based mulch films in the field of sustainable agriculture. Among them, weeding mulch films play significant roles. However, the large-scale production of weeding mulch films through the traditional high-temperature film blowing process would often cause serious pollution due to the diffusion of herbicides in the surroundings. Herein, a green and facile coating approach is developed to produce biodegradable weeding mulch films. In our strategy, a herbicide was added into a poly(vinyl alcohol) aqueous solution with dopamine in it. After the subsequent low-temperature coating procedure on a biodegradable poly(butylene adipate-co-terephthalate)/poly(lactic acid) film, effective weeding mulch films were obtained. The morphology, structure, and mechanical property test results revealed the robustness and stability of the coating, and the pot experiments clearly demonstrated the effective weed suppression ability of the obtained weeding films. Evidently, this strategy to produce biodegradable weeding mulch films is green and facile, exhibiting great prospects in the large-scale production of weeding mulch films and other functional biodegradable mulch films.

Organic Carbon Linkage with Soil Colloidal Phosphorus at Regional and Field Scales: Insights from Size Fractionation of Fine Particles.

Nano and colloidal particles (1-1000 nm) play important roles in phosphorus (P) migration and loss from agricultural soils; however, little is known about their relative distribution in arable crop soils under varying agricultural geolandscapes at the regional scale. Surface soils (0-20 cm depth) were collected from 15 agricultural fields, including two sites with different carbon input strategies, in Zhejiang Province, China, and water-dispersible nanocolloids (0.6-25 nm), fine colloids (25-160 nm), and medium colloids (160-500 nm) were separated and analyzed using the asymmetrical flow field flow fractionation technique. Three levels of fine-colloidal P content (3583-6142, 859-2612, and 514-653 µg kg-1) were identified at the regional scale. The nanocolloidal fraction correlated with organic carbon (Corg) and calcium (Ca), and the fine colloidal fraction with Corg, silicon (Si), aluminum (Al), and iron (Fe). Significant linear relationships existed between colloidal P and Corg, Si, Al, Fe, and Ca and for nanocolloidal P with Ca. The organic carbon controlled colloidal P saturation, which in turn affected the P carrier ability of colloids. Field-scale organic carbon inputs did not change the overall morphological trends in size fractions of water-dispersible colloids. However, they significantly affected the peak concentration in each of the nano-, fine-, and medium-colloidal P fractions. Application of chemical fertilizer with carbon-based solid manure and/or modified biochar reduced the soil nano-, fine-, and medium-colloidal P content by 30-40%; however,the application of chemical fertilizer with biogas slurry boosted colloidal P formation. This study provides a deep and novel understanding of the forms and composition of colloidal P in agricultural soils and highlights their spatial regulation by soil characteristics and carbon inputs.

Response of bacterial communities to mining activity in the alpine area of the Tianshan Mountain region, China.

Anthropogenic activities, such as mining, influence soil bacterial community composition and microbial distributions. In the current study, the patterns in microbial distribution and the environmental drivers shaping the soil bacterial community composition in the alpine mining area of the Tianshan Mountain region, China, were investigated, and the bacterial communities were analyzed using 16S rDNA pyrosequencing. The environmental factors and their relationships with the microbial community composition, structure, and diversity were also assessed. The soil organic carbon (SOC) concentration increased along the elevation gradient, with the highest concentration in the mining area, which increased microbial abundance and species richness. Some metals, like Ca, Cu, Pb, and Zn, accumulated significantly in the tailing area and were negatively correlated with the microbial community structure. Proteobacteria, Acidobacteria, Actinobacteria, and Verrucomicrobia were the dominant phyla; these dominant phyla were more abundant in the areas without mining than in the areas with mining at the same altitude. The relative abundance of Proteobacteria and Verrucomicrobia significantly increased along the elevation gradient, while that of Actinobacteria in the mining camp area was more than twice those in the other areas due to higher soil pH. Soil biomass was the highest in the valley. Collectively, these results elucidate the influence of anthropogenic mining activities on soil microbial communities in alpine mining soils and provide a basis for the future management of heavy metal-contaminated areas using the indigenous dominant bacterial phyla.