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Biochar and organic fertilizer can significantly increase soil organic carbon (SOC) and promote agricultural production, but it is still unclear how they affect forest SOC after. Here, low-quality plantation soil was subjected to four distinct fertilization treatments: (CK, without fertilization; BC, tea seed shell biochar alone; OF, tea meal organic fertilizer alone; BCF, tea seed shell biochar plus tea meal organic fertilizer). Cunninghamia lanceolata (Lamb.) Hook and Cyclobalanopsis glauca (Thunb.) Oersted seedlings were then planted in pots at the ratios of 2:0, 1:1, and 0:2 (SS, SQ, QQ) and grown for one year. The results showed that the BCF treatment had the best effect on promoting seedling growth and increasing SOC content. BCF changed soil pH and available nutrient content, resulting in the downregulation of certain oligotrophic groups (Acidobacteria and Basidiomycetes) and the upregulation of eutrophic groups (Ascomycota and Proteobacteria). Key bacterial groups, which were identified by Line Discriminant Analysis Effect Size analysis, were closely associated with microbial biomass carbon (MBC) and SOC. Pearson correlation analysis showed that bacterial community composition exhibited a positive correlation with SOC, MBC, available phosphorus, seedling biomass, and plant height, whereas fungal community composition was predominantly positively correlated with seedling underground biomass. It suggested that environmental differences arising from fertilization and planting patterns selectively promote microbial communities that contribute to organic carbon formation. In summary, the combination of biochar and organic fertilizers would enhance the improvement and adaptation of soil microbial communities, playing a crucial role in increasing forest soil organic carbon and promoting tree growth. [ABSTRACT FROM AUTHOR]

Soil heavy-metal pollution is one of the most important environmental problems in the world, and seriously endangers plant growth and human health. Microbial remediation has become a key technology in the field of soil heavy-metal remediation due to its advantages of being harmless, green and environmental. In this study, a fungus Penicillium spp. XK10 with high tolerance to cadmium (Cd) and antimony (Sb) was screened from mine slag, and its adsorption characteristics to heavy metals under different environmental conditions were studied. The results showed that at pH0 = 6, C0 (Cd) = 0.1 mM, and the adsorption time was 4 days, the maximum removal rate of cadmium by XK10 was 32.2%. Under the conditions of pH0 = 4, T = 7d, and the initial antimony concentration of 1 mM, the removal rate of antimony by XK10 was the highest, which was 15.5%. This study provides potential microbial materials for bioremediation of heavy metal-contaminated soils. [ABSTRACT FROM AUTHOR]

Water area and waterweed coverage are the key environmental factors for ecological breeding of Eriocheir sinensis in ponds. In order to explore the effects of above two factors on the growth of E. sinensis, three groups of experiments were set up: low coverage small area (C1S1), high coverage small area (C2S1), and high coverage large area (C2S2), and water environmental factors and the growth of E. sinensis were monitored. The results showed that the dissolved oxygen of ponds with different waterweed coverage was significantly different (p < 0.05), and the phosphate in ponds changed significantly from July to October (p < 0.05). The correlation analysis showed that NH3-N and pH were significantly positively correlated (p < 0.05). At the same time, there was a significant negative correlation between NH3-N and DO, H3PO4 and pH (p < 0.05). Further analysis of the relationship between surface area, waterweed coverage and environmental factors revealed that the surface area and waterweed coverage were closely related to NH3-N, H3PO4 and DO. From July to October, the differences in morphology and weight of E. sinensis in different ponds became more and more significant. In terms of growth rate, C1S1 with a small area and low coverage had a downward trend, while C2S1 and C2S2 were the opposite. In the final stage of the experiment, C2S2 had the highest yield (0.1311 kg/m2), and C1S1 had the lowest yield (0.0600 kg/m2). Then, the ponds with high waterweed coverage and large area can bring better benefits. [ABSTRACT FROM AUTHOR]

Soil microorganisms play an important role in regulating a variety of ecological functions. In recent years, the research on ecological restoration after mining has made people more aware of the importance of microbial diversity to ecosystem restoration. The present study investigated the effect of ecological restoration on microbial community structure and its relationship with soil physicochemical properties in the Dabaoshan mining area, China. High throughput sequencing technology was used to analyze and compare the microbial community composition of three types of soil (undamaged area, unrestoration area, and ecological restoration area). The contents of organic carbon, total nitrogen, and total phosphorus were 2.38–12.97 g/kg, 0.39–1.62 g/kg, and 0.99–1.51 g/kg, respectively. In different soil states, undamaged area and ecological restoration area were significantly higher than those in unrestoration area. The results showed that the structure of soil microbial community was significantly correlated with soil physicochemical properties, and formations in the repaired and unrepaired soils were different. Operational Taxonomic Unit (OTU) cluster analysis and diversity index analysis showed that soil microbial community changed at phylum and genus levels. The results showed that at the phylum level, all soil samples contained Firmicutes, Proteobacteria, and actinobacteria. Firmicutes and Proteobacteria of the ecological restoration area (ER1, ER2) were the highest in relative abundance compared with other samples, accounting for more than 45%. Proteobacteria and Acidobacteria were the dominant phylum in the undamaged area (UD), accounting for 32.7% and 22.3%, respectively. It can be seen that soil restoration produced a new dominant population, and Proteobacteria showed an absolute competitive advantage in the mining soil. [ABSTRACT FROM AUTHOR]

Spatial and quantitative assessments of water yield services in watershed ecosystems are necessary for water resource management and improved water ecological protection. In this study, we used the InVEST model to estimate regional water yield in the Dongjiang Lake Basin in China. Moreover, we designed six scenarios to explore the impacts of climate and land use/land cover (LULC) changes on regional water yield and quantitatively determined the dominant mechanisms of water yield services. The results are expected to provide an important theoretical reference for future spatial planning and improvements of ecological service functions at the water source site. We found that (1) under the time series analysis, the water yield changes of the Dongjiang Lake Basin showed an initial decrease followed by an increase. Spatially, water yield also decreased from the lake area to the surrounding region. (2) Climate change exerted a more significant impact on water yield changes, contributing more than 98.26% to the water yield variability in the basin. In contrast, LULC had a much smaller influence, contributing only 1.74 %. (3) The spatial distribution pattern of water yield services in the watershed was more vulnerable to LULC changes. In particular, the expansion of built-up land is expected to increase the depth of regional water yield and alter its distribution, but it also increases the risk of waterlogging. Therefore, future development in the basin must consider the protection of ecological spaces and maintain the stability of the regional water yield function. [ABSTRACT FROM AUTHOR]

Broussonetia papyrifera is an important ecological and economic tree species. The sexual reproduction of B. papyrifera not only has a low germination rate, but also requires high environmental conditions. Therefore, asexual propagation using tissue culture can effectively improve the propagation efficiency of B. papyrifera. In this study, the leaves and budded shoots of B. papyrifera were used as explants, and different concentrations of plant growth regulators were added to Murashige and Skoog medium (MS) to establish a suitable system for explant callus formation, adventitious buds differentiation and rooting. The results showed that MS + 0.50 mg/L naphthaleneacetic acid (NAA) + 0.25 mg/L 6-benzyladenine(6-BA) and MS + 0.25 mg/L NAA + 0.50 mg/L 6-BA were the best mediums for rapid callus induction from leaf explants and shoot explants, respectively. The best medium combination for shoot differentiation and proliferation was MS + 0.05 mg/L NAA + 0.50 mg/L 6-BA, and the high propagation coefficient could also promote adventitious bud growth. The best rooting medium in the establishment of B. papyrifera tissue culture was MS + 0.25 mg/L NAA. Under this condition, the average rooting numbers of leaf explants and shoot explants were 1.71 and 13.86, respectively. In addition, the best transplanting substrate was a mixture of soil:perlite:vermiculite (20:1:1), and the survival rate was 91.1%. This study established a propagation system in vitro culture of B. papyrifera, and provided a reference for tissue culture of other woody plants. [ABSTRACT FROM AUTHOR]

Broussonetia papyrifera is a widely distributed economic tree species, and it is also a pioneer species in adverse environments. In order to investigate the growth and adaptation mechanism of B. papyrifera under cadmium (Cd) contaminated soil, potted experiments were used with six-month treatments to study Cd enrichment and the transportation, morphological and physiological characteristics of B. papyrifera tissues. The results showed that Cd mainly accumulated in the root when the Cd concentration was high (14.71 mg/kg), and the root biomass was significantly reduced by Cd stress although Cd promoted the growth of seedlings. The bioconcentration factors (BCF) increased with the increase in Cd concentration, and reached the maximum value of 0.21 at 14.71 mg/kg. On the contrary, translocation factor (TF) decreased significantly at 8.28–14.71 mg/kg Cd concentration. Cd not only led to the loose arrangement of the xylem vessels of leaves, but also changed the chlorophyll content. However, B. papyrifera could synthesize organic solutes such as soluble protein, soluble sugar and proline to reduce the intracellular osmotic potential. Our study proved that B. papyrifera has good tolerance to Cd stress and is a pioneer tree species for soil and ecological environment restoration. [ABSTRACT FROM AUTHOR]

Spectral reflectance distortions caused by terrain and solar illumination seriously reduce the accuracy of mapping forest carbon density, especially in mountainous regions. Many models have been developed for mitigating or eliminating the terrain effects on the quality of remote sensing images in hilly and mountainous areas. However, these models usually use global parameters, which may lead to overcorrections for regions with poor illumination and steep slopes. In this study, we present a local parameter estimation (LPE) method based on a pixel-moving window for topographic correction (TC), which can be considered as a general optimization framework for most semiempirical TC models. We set seven kernel sizes for the presented framework, which are 15 pixels, 25 pixels, 50 pixels, 100 pixels, 250 pixels, 500 pixels, and 1000 pixels, respectively. The proposed method was then applied to four traditional TC models, Minnaert (MIN), C Correction (CC), Sun Canopy Sensor + C (SCSC) and Statistical Empirical Correction (SEC), to form four new TC models. These new models were used to estimate forest carbon density of a mountainous area in Southern China using field plot data and a Landsat 8 image. Four evaluation methods, including correlation analysis, the stability of land covers, comparison of reflectance between sunlit and shaded slopes, and accuracy assessment of forest carbon density, were employed to evaluate the contributions of moving window sizes, and assess the performance of the TC models for forest carbon density estimation. The results show that the four TC models with LPE perform much better than the traditional TC models in reducing the topographic effects and improving the estimation accuracy of forest carbon density for the study area. Among the traditional TC models, SEC performs slightly better than SCSC, CC, and MIN. Therefore, the SEC-based model with LPE, that is, LPE-SEC, gets greater R2 and smaller relative RMSE values in estimating forest carbon density than other models. Moreover, all the means of the predicted forest carbon density values fall in the confidence interval of the validation data at a significant level of 0.05. Overall, this study implies that the proposed method with LPE provides great potential to improve the performance of TC and forest carbon density estimation for the study area. It is expected that the improved TC method can be applied to other mountainous areas to improve the quality of remotely sensed images. [ABSTRACT FROM AUTHOR]

In this study, Box–Behnken design (BBD) was employed to optimize the process for H3PO4-activated Typha angustifolia activated carbon (TAC) production and Cr removal by TAC; the removal mechanisms were discussed based on TAC characterization, and the regeneration evaluation was also conducted. The optimum preparation conditions were activated time of 1.5 h, temperature of 469.02 °C, and incubation ratio of 4, resulting in an experimental carbon yield of 38.23% and Cr removal of 90.01%. The optimum adsorption parameters were found to be 0.02 g/50 mL TAC, 80 mg/L Cr(VI), and 2.21 pH with the observed Cr adsorption capacity of 59.54 mg/g. The removal mechanisms involved coulombic attraction, ionic exchange, surface complexation, and reduction. The process of Cr(VI) adsorption was feasible, spontaneous, and endothermic in nature, and the pseudo-second-order and Langmuir isotherm models were more appropriate for the removal process. After five adsorption/desorption cycles, the Cr adsorption capacity on TAC reduced by only 24.37%. The results showed that BBD could successfully optimize TAC production and Cr removal, and TAC could be developed as a promising, eco-friendly, and effective adsorbent for Cr pollution control. [ABSTRACT FROM AUTHOR]

Cr(VI) contamination has posed great threat to both the ecosystem and human health for its carcinogenic and mutagenic nature. A highly effective adsorbent for the removal of Cr(VI) was prepared and its adsorption mechanism was thoroughly discussed in this study. In detail, magnetic BiFeO 3 and kenaf biochar were loaded on cross-linked chitosan to obtain chitosan-kenaf biochar@BiFeO 3 (CKB) for improving adsorption capacity towards Cr(VI). The adsorption process of Cr(VI) onto CKB was evaluated as a function of the pH, the existence of competing ions, the initial concentration of Cr(VI) and contact time. The results show that CKB exhibits the highest adsorption capacity under the optimal pH 2.0. The presence of competing ions such as Ca 2+ , NO 3 - , SO 4 2- , and Cl - decreases the adsorption capacity; among them, Ca 2+ and NO 3 - show the greatest hindrance. By studying the effect of initial Cr(VI) concentration on the adsorption capacity, it was found that CKB in the solution was enough to remove Cr(VI) for all treatments (10-200 mg/L). The adsorption experimental data were well fitted with pseudo-first-order model, suggesting that chemisorption is not the dominant rate-limiting step. Freundlich isotherm model can better explain the adsorption process, indicating a non-ideal adsorption towards Cr(VI) on a heterogeneous surface of CKB. A 2 5-1 Fractional Factorial Design (FFD) showed that pH and initial concentration of Cr(VI) have significant influence on Cr(VI) adsorption in our reaction system. In general, excellent adsorption efficiency of CKB indicates that it may be a good candidate for the remediation of Cr(VI)-contaminating wastewater., Competing Interests: The authors declare that they have no competing interests.

A readily separated composite was prepared via direct assembly of Fe₃O 4 magnetic nanoparticles onto the surface of graphene oxide (GO) (labeled as Fe₃O₄@GO) and used as an adsorbent for the removal of tetracycline (TC) from wastewater. The effects of external environmental conditions, such as pH, ionic strength, humic acid (HA), TC concentration, and temperature, on the adsorption process were studied. The adsorption data were analyzed by kinetics and isothermal models. The results show that the Fe₃O₄@GO composite has excellent sorptive properties and can efficiently remove TC. At low pH, the adsorption capacity of Fe₃O₄@GO toward TC decreases slowly with increasing pH value, while the adsorption capacity decreases rapidly at higher pH values. The ionic strength has insignificant effect on TC adsorption. The presence of HA affects the affinity of Fe₃O₄@GO to TC. The pseudo-second-order kinetics model and Langmuir model fit the adsorption data well. When the initial concentration of TC is 100 mg/L, a slow adsorption process dominates. Film diffusion is the rate limiting step of the adsorption. Importantly, Fe₃O₄@GO has good regeneration performance. The above results are of great significance to promote the application of Fe₃O₄@GO in the treatment of antibiotic wastewater., Competing Interests: The authors declare no conflict of interest.