Organic fertilizer substituting 20% chemical N increases wheat productivity and soil fertility but reduces soil nitrate-N residue in drought-prone regions.

Organic fertilizer substitution is an effective measure for increasing both the quantity and quality of wheat grain while reducing chemical fertilizer input. However, the effects of reducing nitrogen (N) fertilizer combined with organic fertilizer substitution on grain yield, grain protein content and protein yield, plant N accumulation and translocation, N use efficiency, soil fertility, N apparent surplus and nitrate-N residue in rain-fed drought-prone areas remains limited. In this study, field experiments were conducted over four consecutive seasons (2019-2023) at two sites with four treatments: zero N application (ZN), farmer N application (FN), reduced 20% N of FN (RN), and organic fertilizer substituting 20% N of RN (OSN). The results showed that compared with the ZN treatment, the FN, RN and OSN treatments increased grain yield and its components, grain protein content and protein yield, aboveground N accumulation at the anthesis and maturity stages, pre-anthesis N translocation, post-anthesis N accumulation, N use efficiency, soil fertility. Compared with RN and FN, OSN increased grain yield by 17.12% and 15.03%, grain protein yield by 3.31% and 17.15%, grain N accumulation by 17.78% and 15.58%, and N harvest index by 2.63% and 4.45% averaged across years and sites, respectively. Moreover, OSN increased the contents of organic matter, total N, available P and available K in both 0-20 and 20-40 cm soil layers, decreased N apparent surplus and nitrate-N residue in 0-100 cm, and pH in both 0-20 and 20-40 cm soil layer. Fundamentally, this study suggests that integrating a 20% reduction N from conventional farmer practices with the utilization of organic fertilizer to replace 20% of the chemical N fertilizer (OSN) represents an effective strategy. This approach shows promise in enhancing wheat grain yield, grain protein yield, and N use efficiency. Additionally, it supports the improvement of soil fertility while simultaneously reducing soil nitrate-N residues and the apparent surplus of N in rain-fed drought-prone regions.

Optimizing Typha biochar with phosphoric acid modification and ferric chloride impregnation for hexavalent chromium remediation in water and soil.

Considering the persistent and covert nature of heavy metal soil contamination, the sustainable development of ecological environments and food safety is at significant risk. Our study focuses on remediating soils contaminated with chromium (Cr); we introduce an advanced remediation material, iron oxide phosphoric acid-loaded activated biochar (HFBC), synthesized through pyrolysis. This HFBC displays greater microporosity, fewer impurities, and enhanced efficiency for the remediation process. Our research utilized a comprehensive set of analytical techniques, including Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS), alongside adsorption studies to elucidate the Cr removal mechanism. The effectiveness of HFBC in remediation was influenced by several factors: the pH level, dosage of HFBC, the initial concentration of Cr, and the ambient temperature. Our results indicated an optimal chromium (VI) adsorption capacity of 55.5 mg/g by HFBC at a pH of 6.0 and a temperature of 25 °C, with the process adhering to the pseudo-second-order kinetic model and the Langmuir adsorption isotherm, thus suggesting spontaneity in the uptake method. Moreover, this mechanism encompasses both adsorption and reduction reactions. Using HFBC in pot experiments with cabbage indicated not only an increase in soil pH and cation exchange capacity (CEC), but also a surge in bacterial community abundance. Significant reductions in bioavailable chromium were also recorded. Interestingly, HFBC addition bolstered the growth of cabbage, while concurrently diminishing chromium accumulation within the plant, particularly notable as the HFBC application rate increased. In summation, the HFBC produced in our study has demonstrated convincing efficacy in removing chromium from aqueous solutions and soil. Moreover, the positive agronomic implications of its use, such as enhanced plant growth and reduced heavy metal uptake by plants, indicate its high potential for operational value in the domain of environmental remediation of heavy metals.

Soil adsorption potential: Harnessing Earth's living skin for mitigating climate change and greenhouse gas dynamics.

Soil adsorption, which could be seen as a crucial ecosystem service, plays a pivotal role in regulating environmental quality and climate dynamics. However, despite its significance, it is often undervalued within the realms of research and policy frameworks. This article delves into the multifaceted aspects of soil adsorption, incorporating insights from chemistry and material science, ecological perspectives, and recent advancements in the field. In exploring soil components and their adsorption capacities, the review highlights how organic and inorganic constituents orchestrate soil's aptitude for pollutant mitigation and nutrient retention/release. Innovative materials and technologies such as biochar are evaluated for their efficacy in enhancing these natural processes, drawing a link with the sustainability of agricultural systems. The symbiosis between soil microbial diversity and adsorption mechanisms is examined, emphasizing the potential for leveraging this interaction to bolster soil health and resilience. The impact of soil adsorption on global nutrient cycles and water quality underscores the environmental implications, portraying it as a sentinel in the face of escalating anthropogenic activities. The complex interplay between soil adsorption mechanisms and climate change is dissected, identifying research gaps and advocating for future investigations to elucidate the dynamics underpinning this relation. Policy and socioeconomic aspects form a crucial counterpart to the scientific discourse, with the review assessing how effective governance, incentivization, and community engagement are essential for translating soil adsorption's functionality into tangible climate change mitigation and sustainable land-use strategies. Integrating these diverse but interconnected strata, the article presents a comprehensive overview that not only charts the current state of soil adsorption research but also casts a vision for its future trajectory. It calls for an integrated approach combining scientific inquiry, technological innovation, and proactive policy to leverage soil adsorption's full potential to address environmental challenges and catalyze a transition towards a more sustainable and resilient future.

Microbial pathways of nitrous oxide emissions and mitigation approaches in drylands.

Drylands refer to water scarcity and low nutrient levels, and their plant and biocrust distribution is highly diverse, making the microbial processes that shape dryland functionality particularly unique compared to other ecosystems. Drylands are constraint for sustainable agriculture and risk for food security, and expected to increase over time. Nitrous oxide (N2O), a potent greenhouse gas with ozone reduction potential, is significantly influenced by microbial communities in drylands. However, our understanding of the biological mechanisms and processes behind N2O emissions in these areas is limited, despite the fact that they highly account for total gaseous nitrogen (N) emissions on Earth. This review aims to illustrate the important biological pathways and microbial players that regulate N2O emissions in drylands, and explores how these pathways might be influenced by global changes for example N deposition, extreme weather events, and climate warming. Additionally, we propose a theoretical framework for manipulating the dryland microbial community to effectively reduce N2O emissions using evolving techniques that offer inordinate specificity and efficacy. By combining expertise from different disciplines, these exertions will facilitate the advancement of innovative and environmentally friendly microbiome-based solutions for future climate change vindication approaches.

Genome analysis of Shewanella putrefaciens 4H revealing the potential mechanisms for the chromium remediation.

Microbial remediation of heavy metal polluted environment is ecofriendly and cost effective. Therefore, in the present study, Shewanella putrefaciens stain 4H was previously isolated by our group from the activated sludge of secondary sedimentation tank in a dyeing wastewater treatment plant. The bacterium was able to reduce chromate effectively. The strains showed significant ability to reduce Cr(VI) in the pH range of 8.0 to 10.0 (optimum pH 9.0) and 25-42 ℃ (optimum 30 ℃) and were able to reduce 300 mg/L of Cr(VI) in 72 h under parthenogenetic anaerobic conditions. In this paper, the complete genome sequence was obtained by Nanopore sequencing technology and analyzed chromium metabolism-related genes by comparative genomics The genomic sequence of S. putrefaciens 4H has a length of 4,631,110 bp with a G + C content of 44.66% and contains 4015 protein-coding genes and 3223,  2414, 2343 genes were correspondingly annotated into the COG, KEGG, and GO databases. The qRT-PCR analysis showed that the expression of chrA, mtrC, and undA genes was up-regulated under Cr(VI) stress. This study explores the Chromium Metabolism-Related Genes of S. putrefaciens 4H and will help to deepen our understanding of the mechanisms of Cr(VI) tolerance and reduction in this strain, thus contributing to the better application of S. putrefaciens 4H in the field of remediation of chromium-contaminated environments.

Cr(VI) removal from wastewater using nano zero-valent iron and chromium-reducing bacteria.

Significant global efforts are currently underway to alleviate the presence of toxic metals in water bodies, aiming to encourage a sustainable environment. Nevertheless, the scientific community has yet to methodically inspect the performance and mechanisms underlying the interaction between nanomaterials and microorganisms in this context. Therefore, this study seeks to address this knowledge gap by developing a novel system that integrates nano zero-valent iron (nZVI) with chromium-reducing bacteria (CrRB) to efficiently remove Cr(VI) from water sources. The combined use of RBC600 and CrRB resulted in a Cr(VI) removal rate of 77.73%, displaying a substantial improvement of 17.61% compared to the use of CrRB alone. The efficacy of Cr(VI) elimination was observed to be affected by several factors within the system, such as the pH value, the quantity of nZVI added, the degree of CrRB inoculation, and the initial concentration of Cr(VI) at the onset of the experiment. When the pH was adjusted to 5, the complete removal of 200 mg/L Cr(VI) was achieved within 36 h. Increasing the dosage of nZVI to above 2 g/L resulted in the complete elimination of Cr(VI) from the solution within 72 h. This can be attributed to the availability of more reaction sites for the reduction of Cr(VI), facilitated by the higher nZVI dose. Additionally, the increased dose of nZVI allowed for the dissolution of more reactive Fe(II) ions. The characterization analysis, high-throughput sequencing, and fluorescence quantitative PCR results have established that CrRB and its extracellular polymer effectively reduce and complex Cr(VI). This process facilitated the dissolution of the passivated layer on the surface of nZVI, thus significantly enhancing the efficiency of nZVI in responding to Cr(VI). Additionally, the presence of nZVI created a favorable living environment for CrRB, resulting in increased richness and diversity within the CrRB community. These findings provide valuable preliminary insights into the mechanism underlying Cr(VI) elimination by the synergistic interaction between nZVI and CrRB. Therefore, this study establishes a solid theoretical foundations for the application of nano-bio synergy in the remediation of Cr(VI).

Characterization of Agronomic and Seed Oil Features for Different Cultivars of Tree Peony.

Tree peony is a unique oil plant resource in China, and tree peony seed oil is one of the healthy edible oils with a very promising future. However, the main oil tree peony cultivars promoted in China are Paeonia ostii 'Fengdan' and Paeonia rockii. In order to explore new oil tree peony cultivars, 68 tree peony cultivars were investigated and cultivars with oil potential were selected by cluster analysis and grey relational analysis (GRA) in this study. The results demonstrated that the 68 cultivars varied significantly in terms of agronomic characteristics (p < 0.05), with the coefficient of variation in seed yield per plant reaching a high of 75.36%. The oil content of 46 cultivars was higher than 'Fengdan' (20.87 ± 0.26%) and 'Zibanbai' (21.24 ± 1.01%), while the alpha-linolenic acids and total unsaturated fatty acid contents of 26 cultivars were higher than 'Fengdan' (39.79 ± 1.13% and 88.99 ± 0.47%) and 'Zibanbai' (40.51 ± 0.09% and 93.59 ± 0.09%). Finally, three cultivars with better integrated traits were selected by cluster analysis and grey relational analysis (GRA), comprising of 'Changshoule', 'Xianchizhenghui', and 'Yupantuojin'. The contents of alpha-linolenic acids and total unsaturated fatty acids in 'Changshoule' (47.98 ± 0.17% and 93.60 ± 0.08%), 'Xianchizhenghui' (49.44 ± 0.63% and 93.80 ± 0.06%), and 'Yupantuojin' (40.46 ± 0.26% and 93.58 ± 0.06%) were higher than that of 'Fengdan' (39.79 ± 1.13% and 88.99 ± 0.47%). In general, these cultivars can be used as hybrid parental materials for breeding new excellent oil tree peony cultivars.

Ascription of nosZ gene, pH and copper for mitigating N2O emissions in acidic soils.

Soil nitrous oxide (N2O) emissions are alarming for global warming and climate change. N2O reduction is carried out only by nosZ gene encoded N2O-reductase, which is highly sensitive to acidic pH and copper (Cu) contents. Therefore, a microcosm study was conducted to examine the attribution of soil pH management, Cu supply and nosZ gene abundance for N2O emission mitigation. Cu was applied at the dose of 0, 10, 25 and 50 mg kg-1 to three acidic soils (Soil 1, 2 and 3) without and with dolomite (0 and 5 g kg-1). Cu application and soil pH increment substantially enlarged the abundance of nosZ gene, and consequently mitigated soil N2O emissions; highest reduction with 25 Cu mg kg-1. Decline in NH4+ and subsequently accumulation of NO3-, and large contents of MBC and DOC in dolomite treated soils led to a substantial N2O reduction. The cumulative N2O emissions were lowest in the treatment of 25 Cu mg kg-1 with dolomite application for each soil. Results suggest that soil pH increment, an adequate Cu supply, and nosZ gene abundance can potentially lower soil N2O emissions in acidic soils.

Fe(III) stabilizing soil organic matter and reducing methane emissions in paddy fields under varying flooding conditions.

The role of iron (Fe) in soil organic matter (SOM) stabilization and decomposition in paddy soils has recently gained attention, but the underlying mechanisms during flooding and drying periods remain elusive. As the depth water layer is maintained in the fallow season, there will be more soluble Fe than during the wet and drainage seasons and the availability of oxygen (O2) will be different. To assess the influence of soluble Fe on SOM mineralization during flooding, an incubation experiment was designed under oxic and anoxic flooding conditions, with and without Fe(III) addition. The results showed that Fe(III) addition significantly (p < 0.05) decreased SOM mineralization by 14.4 % under oxic flooding conditions over 16 days. Under anoxic flooding incubation, Fe(III) addition significantly (p < 0.05) decreased 10.8 % SOM decomposition, mainly by 43.6 % methane (CH4) emission, while no difference in carbon dioxide (CO2) emission was noticed. These findings suggest that implementing appropriate water management strategies in paddy soils, considering the roles of Fe under both oxic and anoxic flooding conditions, can contribute to SOM preservation and mitigation of CH4 emissions.

The effects of continuous straw returning strategies on SOC balance upon fresh straw incorporation.

Continuous straw returning is widely encouraged for augmenting soil organic carbon (SOC) in arable lands. However, the magnitude of changes in net SOC related to native SOC mineralization and new SOC development upon fresh straw incorporation remains elusive, particularly in soils after continuous straw returning with different strategies. To address this, soil that had undergone nine years of straw returning with different strategies (NS, non-straw returning; DS, direct straw returning; IS, indirect straw returning) was incubated with fresh 13C-labeled straw for 45 days. Fresh straw incorporation stimulated native SOC-derived CO2 emission in DS soil, which in turn promoted straw-derived CO2 emission in IS soil. Overall, the amounts of newly developed SOC from straw (2.41-2.59 g C/kg soil) overcompensated for the native SOC losses (0.91-1.37 g C/kg soil) by mineralization, and led to net C sequestration in all treatments. No obvious difference was found in the amounts of SOC sequestrated from straw between the DS and NS soils, while the amount of native SOC mineralization increased by 40-50% in the DS soil relative to other treatments, thus resulting in lower net C sequestration in the DS soil (1.21 g C/kg soil) than IS and NS soil (1.43 and 1.65 g C/kg for IS and NS soil, respectively). Spearman's correlation analyses indicated a significant (p < 0.01) and positive correlation between SOC contents and native soil C mineralization, while the soil microbial index played a greater role in influencing fresh straw sequestration (p < 0.01). In conclusion, the DS soil showed a weaker effect on SOC sequestration than IS after 9 years of practices, upon fresh straw incorporation. This difference may be attributed to the magnitude of native SOC mineralization in the soil. Besides the straw-C input rate, results emphasize that native soil C protection should be also considered in long-term SOC sequestration practices.

Efficient removal of Cr(VI) and As(V) from an aquatic system using iron oxide supported typha biochar.

The removal of Cr(VI) and As(V) from aqueous solutions has been a worldwide concern. In this study, Typha biochar (FBC) with magnetic iron oxide was prepared by impregnating Typha with FeCl3 and performing pyrolysis, and the possible mechanism of Cr(VI) and As(V) removal was investigated by combining characterization means and adsorption experiments. The results showed that the modified Typha biochar is rich in pores and has the potential to eliminate Cr and As through processes such as exchange and reduction. The single molecule uptake capacities of FBC for Cr(VI) and As(V) were 32.82 and 21.56 mg g-1, respectively. The adsorption process is spontaneous heat absorption, and the adsorption results are also consistent with the proposed secondary kinetic model. FBC still had >60% removal efficiency in the second and third reuse of Cr(VI), indicating its good recyclability. Therefore, this study confirms that FBC can effectively remove both Cr(VI) and As(V).

Enzyme activities and organic matter mineralization in response to application of gypsum, manure and rice straw in saline and sodic soils.

Saline and alkaline soils are a challenge for sustainable crop production. The use of organic and inorganic amendments is a common practice to increase the fertility of salt-affected soils that can trigger faster carbon (C) and nitrogen (N) cycling. We examined the effects of gypsum (Gyps), farm manure (Manure) and rice straw (Straw) on enzyme activities, organic matter mineralization and CO2 emissions in two salt-affected soils [Solonchak (saline); pH: 8, electrical conductivity (EC): 6.5, sodium adsorption ratio (SAR): 2.5, and Solonetz (alkaline sodic); pH: 8.9, EC: 1.6, SAR: 17]. Gypsum addition decreased soil pH up to 0.62 and 0.30 units, SAR 1.2 and 5.2 units, and EC 2.9 and 1.4 units in Solonchak and Solonetz, respectively. Dissolved organic C, microbial biomass C, dissolved organic N, mineral N (NO3- and NH4+), enzyme activities (urease, invertase, catalase, phosphatase, phenol-oxidase), alkali extractable phenols, and available phosphorous increased with the application of all amendments in both soils. Solonetz released more CO2 than Solonchak, whereas maximum CO2 emissions were common after manure application (3140 mg kg-1 in Solonchak, and 3890 mg kg-1 in Solonetz). We conclude that high SAR and low EC increase CO2 emissions through accelerated C and N cycling and manure decomposition in Solonetz soils.

Soil pH management for mitigating N2O emissions through nosZ (Clade I and II) gene abundance in rice paddy system.

Soil nitrous oxide (N2O) is produced by abiotic and biotic processes, but it is solely consumed by denitrifying microbes-encoded by nosZ genes. The nosZ gene includes two groups i.e. Clade I and Clade II, which are highly sensitive to pH. Managing pH of acidic soils can substantially influence soil N2O production or consumption through nosZ gene abundance. Nevertheless, the response of nosZ (Clade I and Clade II) to pH management needs elucidation in acidic soils. To clarify this research question, a pot experiment growing rice crop was conducted with three treatments: control (only soil), low dose of dolomite (LDD), and high dose of dolomite (HDD). The soil pH increased from 5.41 to 6.23 in the control, 6.5 in LDD and 6.8 in HDD treatment under flooded condition. The NH4+ and NO3- contents increased and reached the maximum at 30.4 and 21.5 mg kg-1, respectively, in HDD treatment under flooding condition. The contents of dissolved organic carbon and microbial biomass carbon showed a swift rise at midseason aeration and reached maximum at 30.7 and 101 mg kg-1 in the HDD treatment. Clade I, Clade II and 16S rRNA genes abundance increased with the onset of flooding, and occurred maximum in the HDD treatment. A peak in N2O emissions (5.96 µg kg-1 h-1) occurred at midseason events in the control when no dolomite was added. Dolomite application significantly (p ≤ 0.001) suppressed N2O emissions, and HDD treatment was more effective in reducing emissions. Pearson correlation, linear regressions and principal component analysis displayed that increased soil pH and Clade I and Clade II were the main controlling factors for N2O emission mitigation in acidic soil. This research demonstrates that ameliorating soil acidity with dolomite application is a potential option for the mitigation of N2O emissions.

Remediation of Cr(VI)-Contaminated Soil by Biochar-Supported Nanoscale Zero-Valent Iron and the Consequences for Indigenous Microbial Communities.

Biochar/nano-zero-valent iron (BC-nZVI) composites are currently of great interest as an efficient remediation material for contaminated soil, but their potential to remediate Cr-contaminated soils and effect on soil microecology is unclear. The purpose of this study was to investigate the effect of BC-nZVI composites on the removal of Cr(VI) from soil, and indigenous microbial diversity and community composition. The results showed that after 15 days of remediation with 10 g/kg of BC-nZVI, 86.55% of Cr(VI) was removed from the soil. The remediation of the Cr-contaminated soil with BC-nZVI resulted in a significant increase in OTUs and α-diversity index, and even a significant increase in the abundance and diversity of indigenous bacteria and unique bacterial species in the community by reducing the toxic concentration of Cr, changing soil properties, and providing habitat for survival. These results confirm that BC-nZVI is effective in removing Cr(VI) and stabilizing Cr in soil with no significant adverse effects on soil quality or soil microorganisms.

Effects of water regimes on soil N2O, CH4 and CO2 emissions following addition of dicyandiamide and N fertilizer.

Water regimes strongly impact soil C and N cycling and the associated greenhouse gases (GHGs, i.e., CO2, CH4 and N2O). Therefore, a study was conducted to examine the impacts of flooding-drying of soil along with application of nitrogen (N) fertilizer and nitrification inhibitor dicyandiamide (DCD) on GHGs emissions. This study comprised four experimental treatments, including (i) control (CK), (ii) dicyandiamide, 20 mg kg-1 (DCD), (iii) nitrogen fertilizer, 300 mg kg-1 (N) and (iv) DCD + N. All experimental treatments were kept under flooded condition at the onset of the experiment, and then converted to 60% water filled pore space (WFPS). At flooding stage, N2O emissions were lower as compared to 60% WFPS. The highest cumulative N2O emission was 0.98 mg N2O-N kg-1 in N treated soil due to high substrates of mineral N contents, but lowest (0.009 mg N2O-N kg-1) in the DCD treatment. The highest cumulative CH4 emissions (80.54 mg CH4-C kg-1) were observed in the N treatment, while uptake of CH4 was observed in the DCD treatment. As flooded condition converted to 60% WFPS, CO2 emissions gradually increased in all experimental treatments, but the maximum cumulative CO2 emission was 477.44 mg kg-1 in the DCD + N treatment. The maximum dissolved organic carbon (DOC) contents were observed in N and DCD + N treatments with the values of 57.12 and 58.92 mg kg-1, respectively. Microbial biomass carbon (MBC) contents were higher at flooding while lower at transition phase, and increased at the initiation of 60% WFPS stage. However, MBC contents declined at the later stage of 60% WFPS. The maximum MBC contents were 202.12 and 192.41 mg kg-1 in N and DCD + N treatments, respectively. Results demonstrated that water regimes exerted a dramatic impact on C and N dynamics, subsequently GHGs, which were highly controlled by DCD at both flooding and 60% WFPS conditions.

Earthworms promote the transfer of 15N-urea to lettuce while limit appreciably increase 15N losing to environment.

Earthworm activities not only increase nitrogen (N) uptake by crops, but also lead to N losing to environment. Thus, the present study examined the transformation of 15N-labeled urea with and without earthworms (Metaphire guillelmi) in a soil-lettuce system. We evaluated lettuce 15N uptake, 15N losses including N2O emission, NH3 volatilization and leaching, as well as 15N remaining in soil. Results showed that 15N-urea uptakes by lettuce significantly increased from 33.07% to 42.72% with earthworm presence. However, little difference was found on the total amounts of leaching and gaseous losses (N2O emission and NH3 volatilization) from 15N-urea between the treatment with and without earthworms (4.04 and 5.38%, respectively). Most of the 15N-urea remained in the soil, accounting for 48.44% and 60.65% of the 15N-urea in soil with and without earthworm presence. We conclude that earthworms enhanced the transfer of 15N-urea to lettuce without appreciably increasing the 15N-urea loss from soil to the environment.

Appraisal of different land use systems for heterotrophic respiration in a Karst landscape.

Soil respiration, particularly heterotrophic respiration (RH), is a potent source of carbon dioxide (CO2) in the atmosphere. The current research focuses on the evaluation of RH for six land use systems including sloping cropland (SC), shrub land (SD), grassland (GD), shrub & grassland (SGD), newly abandoned cropland (NC) and afforested forest (AF). Heterotrophic respiration showed a diverse seasonal pattern over a year long period that was affected by various soil properties and climatic variables across the six land use systems in a subtropical Karst landscape. The lowest RH scores were found in the SD site (annual cumulative soil CO2 flux: 2447 kg C ha-1), whereas the maximum heterotrophic respiration occurred in the SF site (annual cumulative soil CO2 13597 kg C ha-1). The values of RH were: SC site: 3.8-191.5 mg C m-2 h-1, NC site: 1.04-129 mg C m-2 h-1, GD site: 3.6-100.7 mg C m-2 h-1, SGD site: 0.3-393.5 mg C m-2 h-1, SD site: 3-116 mg C m-2 h-1, and SF site: 10.6-398.2 mg C m-2 h-1. Highly significant (p ≤ 0.01) and positive correlations between RH rate and soil temperature were found for the studied land use types (correlation coefficients as follows; SC: 0.77, NC: 0.61, GD: 0.283, SGD: 0.535, SD: 0.230, SF: 0.85). However, water filled pore space (WFPS), NH4+, NO3-, dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) concentrations showed varied (positive and negative) correlations with RH. The overall results show that soil temperature can be considered as the most limiting factor for RH among all the sites studied in the present research. In these environments, soil heterotrophic respiration significantly correlated with soil temperature, highlighting the significance of climate on heterotrophic respiration.

Appraisal of MsepCSP14 for chemosensory functions in Mythimna separata.

Chemosensory proteins (CSPs) have great contributions in performing diverse functions in insects. However, physiological appraisal of chemosensory protein genes still remains elusive in insects. We studied expression patterns and binding affinities of MsepCSP14, a chemosensory protein, in Mythimna separata. The distinct functions of MsepCSP14 were validated by employing different molecular techniques. The MsepCSP14 had high resemblance of sequence with chemosensory proteins of other insect family members. The MsepCSP14 expression was higher in antennal tissues of females than other tissues. Fluorescence binding assay validated that binding of nine out of 21 ligands to MsepCSP14 was higher at pH 7.4 than at pH 5.0. Three dimensional modeling (3D) and docking analysis predicted that amino acid residues of MsepCSP14 were involved in binding of compounds, and behavior assay displayed that adults of M. separata considerably responded to four volatiles from compounds demonstrating strong binding ability to MsepCSP14. Results of the present study suggest that MsepCSP14 is likely to mediate chemosensory functions in M. separata.

Efficient Removal of Hexavalent Chromium from an Aquatic System Using Nanoscale Zero-Valent Iron Supported by Ramie Biochar.

In this study, ramie biochar (RBC) was used to activate nano zero-valent iron (nZVI) to enhance hexavalent chromium (Cr(VI)) removal. The best results were obtained at a pyrolysis temperature of 600 °C, a biochar particle size of < 150 µm, and an iron to carbon ratio = 1:1. Under the optimal conditions, the removal of Cr(VI) by RBC600-nZVI (98.69%) was much greater than that of RBC600 (12.42%) and nZVI (58.26%). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed that the reaction mechanism at the Fe and Cr interface was a multiple interaction mechanism with reduction dominated, adsorption, and co-precipitation simultaneously. The enhanced performance of RBC600-nZVI resulted from the effective dispersion of nZVI on the surface of RBC600, therefore increasing the adsorption activity sites. At the same time, RBC600 and nZVI exerted a synergistic influence on the composite structure, which jointly promoted the reduction reaction of Cr(VI) and removed more Cr(VI). This study shows that RBC-nZVI is a potentially valuable remediation material that not only provides a new idea for the utilization of ramie waste, but also effectively overcomes the limitations of nZVI, thus, achieving efficient and rapid remediation of Cr(VI).