281. 题目: Effective indicators and drivers of soil organic matter in intensive orchard production systems
Soil organic matter (SOM) is critical for the sustainable development of intense agroecosystems such as orchard production systems. Nevertheless, the status and drivers of SOM are indecipherable in different orchard systems due to the perennial anthropogenic influences and complex multicollinearity of soil properties. Thus, the present work aimed to address these issues using indicator transformation, data dimension reduction, and geostatistical method. We selected two orchard systems (open field and plastic shed) with similar mean SOM contents (approximately 15 g kg−1). Our results revealed that the average stratification ratio of SOM was significantly greater in open field orchards (2.20 ± 0.93) than in plastic shed orchards (1.75 ± 0.71) (p < 0.05). Likewise, the SOC/clay ratio in open field orchard soils (0.096 ± 0.051) was significantly higher than that in plastic shed orchards (0.088 ± 0.025) (p < 0.01). The variance analysis of these two indicators suggested a greater soil fertility in open field orchards than plastic shed. The main drivers of SOM in different orchard systems were different. In open field orchards, the terrain (q=0.36), soil ion processes (q=0.34), and soil types (q=0.31) were the dominant factors of affecting spatial variability of SOM, while the soil texture (q=0.44), soil types (q=0.32) and terrain (0.30) mainly explained the spatial heterogeneity of the SOM in plastic shed orchards. Outputs of this research provide a guidance for training the farmers to improve orchard SOM, as well as a reference for investigators to further explore the SOM influencing factors.
282. 题目: Application of biochar to anaerobic digestion versus digestate: Effects on N emissions and C stability
Research attention is growing for biochar as amendment for anaerobic digestion (AD), as it may improve both the AD process and digestate properties. In this study, two biochars (from insect frass or the woody fraction of green waste, both pyrolyzed at 450 °C) were added (5 % w/w) during semi-continuous AD of organic kitchen waste and chicken manure. Biochar was mixed either during the AD process or to the digestate post-treatment. The impact of biochar addition on the AD process, NH3 and greenhouse gas emissions, as well as C and N mineralization following soil application, was examined. Biochar did not affect the biogas yield, but did lead to a reduction in NH3 levels in the biogas and NH4+-N sorption onto the biochars, reducing the risk of AD inhibition. N sorbed as NH4+-N onto the biochar was more available for mineralization than N sorbed as NH3. N sorption on biochar-amended digestates did not result in trade-offs when these digestates were applied to soil: the sorbed N was not released as NH3 or N2O after soil application and was not released as mineral N in either the short or medium term. The C-rich biochars increased the OC content of the digestate, which enhanced its value as soil improver. Additionally, mixing biochar with digestate decreased the soil CO2 emissions up to 33 % when it was added after AD; no priming effects were observed. These findings highlight the potential benefits of incorporating biochar into AD systems and the subsequent application of biochar-amended digestate in agricultural practices.
283. 题目: Spatial variation of soil organic matter and metal mobility in wetland soils: Implications for biogeochemical processes in lateritic landscape
The evolution of the lateritic landscape over time changes the path of pedogenesis and soil hydrology. The occurrence of upland wetlands in the savannah flat plateau transforms well-drained lateritic soils into hydric soils enriched in organic matter. We investigated the composition of soil organic matter (SOM) produced in a wetland and their link with the mineral constituents of soil and their contribution to the mobility of Si, Fe, and Al in the soil. Six tranches were opened in a soil catena located from the plateau toward the center of the wetland, representing different hydromorphic features. Soil morphology was described, and chemical, physical and mineralogical analyses were performed to evaluate soil properties. Chemical fractionation of Soil Organic Matter (SOM) was performed and total organic carbon (TOC), dissolved organic carbon (DOC), particulate organic carbon (POC), and water-extractable organic matter (WEOM) were determined in the soil horizons. Metal complexing properties of DOM were determined using an excitation-emission matrix of fluorescence. The occurrence of Fe eluviation in the superficial horizons, Fe2O3 enrichment in the mottled horizons, and ferricrete formation in the center of the wetland were observed. Geochemical transfer assessment and the variation of oxides within the horizons showed that Fe2O3 and SiO2 were more mobile than Al2O3, whose variability in the gley horizon reflected the mobility of Fe2O3 and SiO2. The stability constants of Al and Cu showed an increase with the depth for WEOM and SOM. The pattern of the organic carbon fraction varied according to the level of hydromorphy and soil depth. It was also observed an increase in the C/N ratio with depth, possibly related to the reduced bioavailability of DOC due to its adsorption with soil solids.
284. 题目: Biochar reduces the cadmium content of Panax quinquefolium L. by improving rhizosphere microecology
Cadmium (Cd) accumulation in American ginseng (Panax quinquefolium L.) can negatively impact its yield and safety. Our previous study found that biochar could reduce cadmium content of P. quinquefolius, however, the mechanism was yet to be elucidated. In the present study, we tested four treatments in order to reveal the mechanism by which this phenomenon occurs: control, Cd, Cd + biochar and biochar. The results showed that the following responses were induced by the addition of biochar under Cd stress. Firstly, the soil physicochemical properties were improved, this is especially true for the soil pH value and soil organic matter content, which were increased by 20.42 % and 15.57 %, respectively. Secondly, the relative abundances of several beneficial microorganism phyla; such as Proteobacteria, Bacteroidota and Actinobacteria; were increased by 10.69 %, 20.11 % and 60.86 %, respectively. Thirdly, treatment with biochar reduced the Cd content by increasing cadmium-chelated metabolites within the soil (e.g., naringenin, caffeic acid, and valine) and increasing detoxification substances in plants (e.g., malic acid, flavonoids, and fumaric acid). Changes in these metabolites were significantly correlated with rhizosphere microecology. In summary, biochar treatment reduced the Cd content in seedlings by improving the soil properties, rhizosphere community, soil metabolites, and plant metabolites.
285. 题目: Utilization of phosphoric acid-modified biochar to reduce vanadium leaching potential and bioavailability in soil
Remediating vanadium (V) polluted soil has garnered widespread attention over the past decade. Yet, few research projects have investigated the stabilization of soil V using modified biochar, so the effects and interacting mechanisms between soil properties and modified biochar for V immobilization and stabilization remain unclear. Hence, this gap is addressed by determining the leaching behavior and mechanisms of soil V on different dosages of phosphoric acid (H3PO4) impregnated biochar (MLBC, 0.5%–4%). The applicability and durability in soil V immobilization was investigated under acid precipitation. The MLBC effect on V bioavailability and mobility was assessed first by CaCl2, Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) extractions in different periods. The V concentrations significantly reduced in CaCl2, TCLP, and SPLP extract with MLBC at each dosage (30 d), while slight to significant increase in SPLP and TCLP extract V was recorded in a long-term incubation (90 d). Column leaching test further demonstrated the high durability of 4% MLBC in V stabilization under continuous acid exposure. Compared to the control (no-biochar), the accumulated V content in the leaching solution significantly decreased in MLBC-amended soil. Acid soluble fraction of V showed significant negative correlation with both soil organic matter (SOM) and available P, which was positively correlated with pH, suggested that pH, available P and SOM were key factors affecting the bioavailability of V in soil. Moreover, combining with the characterization results of MLBC and amended soil, the results revealed that H3PO4 modified biochar played a vital role on V immobilization and soil improvement by forming electrostatic adsorption, ion exchange, redox reaction or complexation with the increase of functional groups. These revealed an efficient and steady development of soil quality and treatment for soil V contamination, under MLBC operation to soil polluted with exogenous V.
286. 题目: Predicting regional soil organic matter content utilizing conventional satellites: Assessing the influence of temporal, spatial, and spectral disparities
Using remote sensing images to predict the spatial distribution of SOM content is a classic digital soil mapping problem. The purpose of this study is to compare the SOM mapping performance of Landsat 8 OLI, Landsat 7 ETM +, Sentinel-2 MSI and MODIS. We take the dry land in the black soil area of Northeast China as the study area and 791 soil samples were collected in the field to directly measure the SOM content, which serves as the evaluation dataset. We used four images to synthesize soil images for May over multi-year periods. May was identified as the best time of year to image the bare soil in Northeast China. All images used for the median synthesis consisted of cloud masked datasets acquired in May. Then, the image band, spectral index were used as inputs, and the SOM mapping results derived from the different satellite images was evaluated using the random forest regression algorithm. In addition, we use simulation methods to evaluate the impact of temporal, spatial, and spectral differences on SOM mapping. The results show that (1) Landsat-8 is currently the best choice for SOM mapping, Sentinel-2 images have the most potential for future SOM mapping, Landsat-7 and MODIS images can provide support for determining the historical spatial distribution of SOM content; (2) improving the temporal, spatial, and spectral resolution of images can improve the accuracy of SOM prediction, and temporal resolution is the most important because higher temporal resolution makes the selection of image pixels more conducive to accurate SOM prediction, thereby reducing the impact of the field environment; and (3) there is little difference in the spatial distribution trends and average values identified from the SOM products obtained from the four satellites, and can be generalized in some application scenarios.
287. 题目: Understanding the stimulation of microbial oxidation of organic N to nitrate in plant soil systems
In the soil N cycle, heterotrophic nitrification is poorly understood. Our understanding of the factors controlling soil heterotrophic nitrification requires support from investigations in the presence of plants. In this study, a series of 15N tracing pot experiments using maize (Zea mays L.) was conducted and the heterotrophic nitrification rate (ONrec) and maize N uptake rate were estimated using the NtracePlant tool to explore the mechanisms that stimulate heterotrophic nitrification by plants. The results showed that the ONrec (0.79–3.67 mg N kg−1 d−1) was much higher in the presence of maize than in the control (CK, no plants, <0.10 mg N kg−1 d−1). After the maize was removed, the ONrec decreased significantly, becoming similar to that of CK. These results indicated that the ONrec was stimulated by the presence of plants. The ONrec declined rapidly to 0.16 and 0.13 mg N kg−1 d−1 after the maize was covered with a black box for 2 and 4 days (preventing photosynthesis), respectively. Meanwhile, the soil dissolved organic carbon (DOC) concentration decreased significantly after photosynthesis was prevented. Moreover, the ONrec correlated significantly with the soil DOC content (P < 0.05). These results revealed that root exudates derived from plant photosynthesis were the key factors that altered soil organic matter, thereby accelerating heterotrophic nitrification. We also found that the maize NO3− uptake rate correlated significantly and positively with the ONrec (P < 0.01), suggesting that the stimulation of heterotrophic nitrification by plants played an important role in the supply of NO3− to meet the N requirements of maize and microorganisms.
288. 题目: Soil geochemistry prevails over root functional traits in controlling soil organic carbon fractions of the alpine meadow on the Qinghai-Tibet Plateau, China
Alpine meadow occupies ～46.7 % of the grassland area and stores more than 60 % of the soil organic carbon (SOC) in the Qinghai-Tibet Plateau, with 3.19 Pg C in the top 30 cm. Parent material can highly influence SOC stocks via various mineral components with divergent adsorption abilities. However, previous studies mainly concentrated on the relation between SOC and parent material in temperate and tropical forest ecosystems, evidences from different environments are needed to gain a holistic understanding. In this study, we explored how the functional distinct SOC fractions (the particulate (POC), mineral-associated (MAOC), and hot-water extractable carbon (HWEOC)) vary among four types of parent materials (monzonitic granite (MG), slate (SL), muscovite schist (SH), and diorite (DI)) by measurements from 16 sites on the Qinghai-Tibet Plateau. We also assessed the plant and geochemical factors in controlling the divergent SOC fractions. We found that MAOC and HWEOC vary strongly, while POC remain stable among parent materials due to sufficient plant input and slow decompositions rate. Moreover, our results revealed that geochemical factors exert dominant controls on each SOC fraction, with soil pH and texture showing a significant influence. Soils developed from the SL displayed the highest MAOC and HWEOC compared with that formed on the other three parent materials due to finer soil texture as well as relative high multivalent Ca and Mg. Furthermore, root traits increased its control on SOC fractions in relatively deeper soil depth (10–30 cm). Taken together, these results provided evidence of the key role of parent material in controlling the divergent SOC fractions in the less weathered alpine regions, emphasizing that parent material and soil geochemistry should be adequately considered in the biogeochemical and Earth system models.
289. 题目: Photo-Reactivity of Dissolved Black Carbon Unveiled by Combination of Optical Spectroscopy and FT-ICR MS Analysis: Effects of Pyrolysis Temperature
Dissolved black carbon (DBC) has high photoactivity, which plays an important role in contaminants photodegradation. However, it is unclear how pyrolysis temperatures would affect the composition and photo-reactivity of DBC at the molecular level. Herein, we combined complementary techniques to study the characteristics of DBC pyrolyzed at 200 - 500 ℃, as well as the photoproduction of reactive species and the photodegradation of tetracycline (TC). Bulk composition characterization found that condensed aromatic carbonyl compounds (ConAC) with narrow molecular weights in DBC experienced an increase from 200 to 500°C, which enhanced the photoproduction of 3DBC*,1O2, and ·OH. Molecular-level data suggested that 3DBC* and 1O2 were both related to the same DBC compounds. Comparatively, the patterns for ·OH were less pronounced, implying its precursor was not 3DBC* and had more complexity. Plentiful CHOx species of ConAC in DBC400 and DBC500 (DBCT, where T = pyrolysis temperature) accelerated the generation of 3DBC* and 1O2, enhancing the photodegradation of TC, and mainly triplet states of quinones reacted with TC. In contrast, DBC200 and DBC300 exhibited inhibition since massive CHOx species in lignin-like reduced 3TC* to TC. Our data revealed the diverse photochemical behavior mechanisms of DBC pyrolyzed at 200 – 500 ℃ at the molecular level and the implications for aquatic contaminants photochemistry.
290. 题目: Ensuring safety standards in sewage sludge-derived biochar: Impact of pyrolysis process temperature and carrier gas on micropollutant removal
The application of sewage sludge to agricultural land is facing increasing restrictions due to concerns about various micropollutants, including polycyclic aromatic hydrocarbons (PAHs), dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), per- and poly-fluoroalkyl substances (PFAS), and heavy metals (HMs). As an alternative approach to manage this residue, the use of pyrolysis, a process that transforms sludge into biochar, a carbon-rich solid material, is being explored. Despite the potential benefits of pyrolysis, there is limited data on its effectiveness in removing micropollutants and the potential presence of harmful elements in the resulting biochar. This study aims to evaluate the impact of the temperature and the use of a carrier gas (N2) during a two-stage pyrolysis and cooling on micropollutant removal. Pilot-scale tests showed that a higher temperature (650 °C) and the use of a carrier gas (0.4 L/min N2) during the pyrolysis and the cooling process led to a reduction of PAHs, PCDD/Fs, PCBs and PFAS below their detection limits. As such, the generated biochar aligns with the guidelines set by the International Biochar Initiative (IBI) and the European Biochar Certificate (EBC) for all micropollutants, except for zinc and copper. Additional investigation is required to determine whether the micropollutants undergo destruction or transition into other pyrolysis end-products, such as the gas or liquid phase.
291. 题目: New perspectives on organic carbon storage in lake sediments based on classified mineralization
The burial amount of organic carbon (OC) in lake sediments is constantly changing owing to mineralization. Statically measured OC does not entirely reflect the dynamic OC processes in lake sediments. This study proposes a dynamic deposition and mineralization model for sedimentary OC (DMSOC) and applies it to eight sedimentary cores from two lakes to invert the history of OC in sediments. The results showed that the trophic level and temperature of the lake predominantly affected the amount of deposited OC (De-OC). The amount of mineralized OC in the sediments is adversely affected by the end sources, burial time, and trophic level of the lake. The OC end source mainly determined the mineralization rate in the following order: algae > aquatic > terrestrial sources. Burial time primarily affected the compositional characteristics of the remaining OC, owing to the asynchronous mineralization of OC from different sources. The De-OC of Dianchi Lake, a eutrophic lake, increased more than twice compared to that of the scenario 100 years ago. The De-OC content of Fuxian Lake, an oligotrophic lake, decreased by approximately 25 %. The greenhouse effect may further reduce the carbon sequestration capacity of lakes, particularly oligotrophic lakes. With a set burial age, the model results show that the increase in OC storage in lake sediments may be much lower than expected. Therefore, the roles of different types of lakes in the carbon cycle must be reassessed.
292. 题目: Biochar loaded with ferrihydrite and Bacillus pseudomycoides enhances remediation of co-existed Cd(II) and As(III) in solution
Bioremediation is one of the effective ways for heavy metal remediation. Iron-modified biochar (F@BC) loaded with Bacillus pseudomycoides (BF@BC) was synthesized to remove the coexistence of cadmium (Cd) and arsenic (As) in solutions. The results showed that B. pseudomycoides significantly increased the removal rate of Cd(II) by enhancing the specific surface area and Si-containing functional groups of biochar (BC). The surface of F@BC was enriched with Fe-containing functional groups, significantly improving As(III) adsorption. The combination of ferrihydrite and strains on BF@BC enhanced the removal of Cd(II) and As(III). It also promoted the oxidation of As(III) by producing an abundance of hydroxyl radicals (·OH). The maximum saturated adsorption capacity of BF@BC for Cd(II) and As(III) increased by 52.47% and 2.99 folds compared with BC, respectively. This study suggests that biochar loaded with Fe and bacteria could be sustainable for the remediation of the coexistence of Cd(II) and As(III) in solutions.
293. 题目: Drivers of organic carbon stocks in eutrophic lake sediments after reestablishment of submerged aquatic vegetation
294. 题目: Efficiently simultaneous sorption and oxidation of antimonite on nitroso grafting-manganese loading binary-modified biochar from aqueous solution
Modification of the biochar platform with organic reagents could enrich active functional groups, and incorporation of magnetic mineral on it could facilitate separation from the aqueous solution after practical application. The present research took advantage of both by performing -NO2 grafting and MnOx loading binary modification on biochar derived from bagasse. The results demonstrated that the binary modification dramatically enhanced the antimonite (Sb(III)) adsorption ability of the sole-modified biochar. The Sb(III) sorption experiment revealed the optimal binary modified parameters were 300°C pyrolysis temperature and the reagent doses of 2.0 g urea, 1.0 g NaOH, 1.5 mL CCl4, 2.0 g NaNO2, and 0.1 g KMnO4. Binary-modified biochar synthesized under the optimal condition (MNBC300) could efficiently remove Sb(III) in the aqueous solution with an adsorption amount of 142.86 mg/g, which was much higher than that of the sole (27.70 and 13.43 mg/g). At a fast rate, the Sb(III) sorption behavior was governed by multilayer heterogeneous chemisorption adsorption via the complexation between -NO2/Mn-O bond and Sb(III). Fitting peaks on X-ray photoelectron spectra (XPS) demonstrated the oxidizability of MNBC300 due to the electron transfer from Sb(Ⅲ) to Mn3+, which was thereby oxidizing Sb(Ⅲ) to less toxic Sb(V). Overall, the present study showed a novel biochar modification technique to eliminate the ecological and human health hazards of Sb-containing wastewater.
295. 题目: A high-resolution map of soil organic carbon in cropland of Southern China
An accurate and fine map of soil organic carbon (SOC) plays a vital role in understanding the global carbon cycle and achieving soil carbon sequestration potential. Although global and national maps of SOC are already available with various spatial resolutions, limited sample size, and relative coarse resolution hinder its accuracy and application in local regions. Here, we collected 13,424 soil samples and information of 45 environmental covariates from cropland in Jiangxi Province, Southern China during 2012 and 2013. Then, the optimal covariates were selected by a recursive feature elimination algorithm for mapping SOC. After that, we deployed the random forest (RF) to produce a fine map (30 m) of SOC in the cropland of Jiangxi Province and 100 times bootstrapping was performed to calculate the prediction uncertainty. Finally, we determined the impacts of various covariates on SOC variability using RF and partial least squares structural equation modeling. Our results showed that compared with the predictive model without soil management information, introducing soil management information improved the predictability of SOC with an increase in R2 by 7.35 % (0.73 vs 0.68) and decrease in RMSE by 7.03 % (2.91 vs 3.13 g kg−1). Our results well estimated the uncertainty of the predicted result with a PICP of 0.91 for a 90 % prediction interval. Soil properties and soil management activities make the largest contribution for modelling SOC. Specifically, the total nitrogen content, straw return amount, total potassium content, and multi-resolution valley bottom flatness were found as the most important factors for mapping SOC in the cropland of our study area. Overall, this study deepened our knowledge of the variation of SOC and also emphasizes that incorporating soil management information could help us to achieve more accurate predictions of SOC.
296. 题目: Advances in Fe-modified lignocellulosic biochar: Impact of iron species and characteristics on wastewater treatment
Lignocellulosic biomass is an attractive feedstock for biochar production owing to its high abundance and renewability. Various modified biochars have been extensively studied for wastewater treatment to improve the physical and chemical properties of lignocellulosic biochar (L-BC). Particularly, Fe-modified L-BCs have garnered attention owing to the abundance and eco-friendliness of Fe and the outstanding ability to remove various organic and inorganic contaminants via adsorption, oxidation, reduction, and catalytic reactions. Different iron species (e.g., Fe(0), Fe (hydr)oxide, Fe sulfide, and Fe-Metal) are formed during the preparation of Fe-L-BCs, which can completely differentiate the physical and chemical properties of BCs. This review discusses the advances in the synthesis of different Fe-L-BCs, specific changes in the physical and chemical properties of Fe-L-BCs upon Fe addition, and their impacts on wastewater treatment. The results of this review can demonstrate the unique advantages and drawbacks of Fe-L-BCs for the removal of different types of pollutants.
297. 题目: Long-term biogas slurry application increases microbial necromass but not plant lignin contribution to soil organic carbon in paddy soils as regulated by fungal community
Biogas slurry (BS) is widely considered as a source of organic matter and nutrients for improving soil organic carbon (SOC) sequestration and crop production in agroecosystems. Microbial necromass C (MNC) is considered one of the major precursors of SOC sequestration, which is regulated by soil microbial anabolism and catabolism. However, the microbial mechanisms through which BS application increases SOC accumulation in paddy soils have not yet been elucidated. A 12-year field experiment with four treatments (CK, no fertilizers; CF, chemical fertilizer application; BS1 and BS2, biogas slurry application at two nitrogen rates from BS) was conducted in rice paddy fields. The results showed that long-term BS application had no effect on lignin phenols proportion in SOC relative to CF. In contrast, BS application elevated the MNC contribution to SOC by 15.5–20.5 % compared with the CF treatment. The proportion of fungal necromass C (FNC) to SOC increased by 16.0 % under BS1 and by 25.8 % under BS2 compared with the CF treatment, while no significant difference in bacterial necromass C (BNC) contribution to SOC was observed between the BS and CF treatments. The MNC was more closely correlated with fungal community structures than with bacterial community structures. We further found that fungal genera, Mortierella and Ciliophora, mainly regulated the MNC, FNC and BNC accumulation. Collectively, our results highlighted that fungi play a vital role in SOC storage in paddy soils by regulating MNC formation and accumulation under long-term BS application.
298. 题目: Effect of NH4+ and NO3− cooperatively regulated carbon to nitrogen ratio on organic nitrogen fractions during rice straw composting
The purpose of this study was to examine the effects of replacing urea with inorganic nitrogen on the organic nitrogen sequestration process and the mitigation of nitrogen loss during rice straw composting. These groups include a control group with urea addition (CK), a group with (NH4)2SO4 addition (NH), a group with KNO3 addition (NO), and a group with (NH4)2SO4 + KNO3 addition (NN). The results demonstrated that adding NH, NO, and NN significantly increased the content of bioavailable organic nitrogen in the compost. Furthermore, compared to the CK, the NH treatment reduced nitrogen loss by 8.41 %. Structural equation modeling revealed the correlation between bacterial communities and organic nitrogen fractions in different treatment groups. Comparisons of nitrogen efficacy and nitrogen loss indicated that adding (NH4)2SO4 was more effective during composting, which provided a meaningful research basis for rice straw composting.
299. 题目: Hydrothermal synthesis of LDO/vinasse biochar composites with ultra-high specific surface areas for phosphate remediation and fertilizer utilization
In this work, CaMgAl-layered double oxide/biochar (LDO@BC) composites were elaborated by hydrothermal coprecipitation and calcination for the efficient recovery of phosphate as well as the further application of the reclaimed composites as fertilizers. On the one hand, the appropriate selection of biochar derived from vinasses as the substrates could solve the limitations of LDO like low specific surface areas as well as poor dispersion. The obtained composites possess the ultrahigh specific surface area as high as 508.97 m2/g. Therefore, a maximum adsorption capacity of 153.64 mg/g is achieved. In addition, our composites are with fast adsorption rates that nearly 100 % phosphate could be removed within 60 s at a trace concentration owing to the large specific surface areas. On the other hand, the recovered adsorbents could be used as fertilizers because of the high contents of P, Ca and Mg elements. The phosphate-adsorbed LDO@BC (P-LDO@BC) demonstrated a positive fertilization effect, significantly accelerating plant growth with length increment by 0.75 times and mass increment by 2.09 times compared with the control groups. Thus, this work not only provides a new approach for waste vinasse utilization, but also presents a promising adsorbing material for phosphate recovery and reuse.
300. 题目: Biochar co-pyrolyzed from peanut shells and maize straw improved soil biochemical properties, rice yield, and reduced cadmium mobilization and accumulation by rice: biogeochemical investigations
Biochar is an eco-friendly amendment for cadmium (Cd) contaminated soils remediation. However, little attention has been paid to the influence and underlying mechanisms of the co-pyrolyzed biochar on the bioavailability and uptake of Cd in paddy soils. The current study explored the effects of biochar co-pyrolyzed from peanut shells (P) and maize straw (M) with different mixing ratios (1:0, 1:1, 1:2, 1:3, 0:1, 2:1 and 3:1, w/w), on the bacterial community and fractionation, mobilization, and uptake of Cd by rice in paddy soil. Biochar addition, particularly P1M3 (P/M 1:3), significantly elevated soil pH and cation exchange capacity, transferred the mobile Cd to the residual fraction, and reduced Cd availability in the rhizosphere soil. P1M3 application decreased the concentration of Cd in different rice tissues (root, stem, leaf, and grain) by 30.0%-49.4%, compared to the control. Also, P1M3 enhanced the diversity indices and relative abundance of iron-oxidizing bacteria in the rhizosphere soil. Moreover, P1M3 was more effective on promoting formation of iron plaque and thus increased the Cd sequestration by iron plaque than the other treatments. Consequently, the highest yield and lowest Cd accumulation of rice were observed after P1M3 amendment. This study revealed the feasibility of applying P1M3 for improving Cd remediation in contaminated soils.