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31881. 题目: Winter tillage with the incorporation of stubble reduces the net global warming potential and greenhouse gas intensity of double-cropping rice fields
文章编号: N18062565
期刊: Soil and Tillage Research
作者: Yuting Yang, Qiong Huang, Haiyang Yu, Kaifu Song, Jing Ma, Hua Xu, Guangbin Zhang
更新时间: 2018-06-25
摘要: Tillage with the incorporation of stubble is a common practice in rice cultivation, but its effect on the net global warming potential (GWP) and greenhouse gas intensity (GHGI) is poorly documented. A three-year field experiment in a double-cropping rice system was conducted to investigate the rate of sequestration of soil organic carbon, CH4 and N2O emissions, the net GWP and the GHGI. Two timings of tillage with three amounts of stubble incorporation were prepared: winter tillage (tillage after the harvest of late rice) and spring tillage (tillage before the transplantation of early rice) with no (0 t ha 1), low (3.5 t ha 1) and high (5.2 t ha 1) amounts of stubble incorporation. The results showed that the rates of sequestration of soil organic carbon with the incorporation of stubble were 0.85–1.06 t C ha 1 yr 1 for winter tillage, 67–429% higher than for spring tillage. Winter tillage significantly increased CH4 and N2O emissions in the winter fallow season relative to spring tillage, whereas it tended to decrease both emissions in the early and late rice seasons, thus playing a small part in the annual emissions. The total CH4 and N2O emissions averaged 106.5–198.2 kg ha 1 yr 1 and 114.4–229.4 g N ha 1 yr 1, respectively. Significant decreases in the net GWP (46–82%) and GHGI (49–84%) were observed when changing the tillage practices with the incorporation of stubble from spring to winter. Compared with high levels of stubble incorporation, winter tillage with low levels of stubble incorporation significantly decreased both the net GWP and the GHGI. The total grain yield was 13.0–13.3 t ha 1 yr 1 for winter tillage, 3–5% higher than for spring tillage. These findings suggest that tillage with the incorporation of stubble in the winter fallow season, particularly with 3.5 t ha 1 stubble, is an effective strategy to mitigate the net GWP and GHGI while maintaining a high grain yield in the double-cropping rice system.

31882. 题目: Degradation of atrazine and structurally related s-triazine herbicides in soils by ferrous-activated persulfate: Kinetics, mechanisms and soil-types effects
文章编号: N18062564
期刊: Chemical Engineering Journal
作者: Liwei Chen, Xiaoxin Hu, Ying Yang, Canlan Jiang, Cheng Bian, Chao Liu, Miaoyue Zhang, Tianming Cai
更新时间: 2018-06-25
摘要: The occurrence of s-triazine herbicides in soils and groundwaters has been reported globally and remediation of these contaminated sites are essentially imperative, especially at accidental spill sites. Present work investigated the feasibility of using Fe2+ catalyzed persulfate (PS) to effectively degrade s-triazine herbicides (e.g., atrazine (ATZ), terbuthylazine (TEA) and ametryn (AMT)) in soils. The degradation kinetics, mechanisms and soil-types effects were systematically investigated. For arable soil A1, extent of degradation reached 80% for 100 mg kg 1 ATZ contaminated soil after 600 min (PS/Fe2+ of 16.6 mM/16.6 mM) at 23 °C. Increasing PS and Fe2+ dosages could enhance ATZ degradation. Acidic condition was favorable for the degradation of ATZ with Fe2+/PS process and the contribution of SO4 to the overall degradation of ATZ decreased as initial pH increased. The ethyl group and chloride substituent on molecular structure of ATZ affected its degradation comparing to other two s-triazine herbicides. ATZ degradations in two arable soils and one paddy soil indicated that different soils with various physical-chemical properties, such as soil organic matter, available and total Fe contents, may influence the ATZ degradation. Moreover, a total of five degradation products of ATZ were identified in soil A1 by Fe2+/PS process. Three degradation pathways including alkyl chain oxidation, dealkylation and dechlorination-hydroxylation reactions with the underlying oxidation mechanisms were tentatively proposed.

31883. 题目: Effects of dissolved and fixed humic acid on Eu(III)/Yb(III) adsorption on aluminum hydroxide: A batch and spectroscopic study
文章编号: N18062563
期刊: Chemical Engineering Journal
作者: Zhulin Niu, Toshihiko Ohnuki, Eric Simoni, Qiang Jin, Zongyuan Chen, Wangsuo Wu, Zhijun Guo
更新时间: 2018-06-25
摘要: Humic acid (HA) in the environment may exist in either dissolved or fixed forms. However, laboratory studies usually take only the former into account. Here we synthesized a hybrid of HA and aluminum hydroxide (Al(OH)3) to mimic fixed HA, compared the effects of fixed and dissolved HA on Eu(III)/Yb(III) adsorption on Al(OH)3, and analyzed the adsorption mechanisms using time resolved laser induced fluorescence spectroscopy (TRLFS), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). It was found that dissolved HA affected significantly Eu(III)/Yb(III) adsorption on Al(OH)3, whereas fixed HA showed little apparent effect on the adsorption. The spectra of TRLFS, XPS and EXAFS for Eu(III)/Yb(III) adsorption on Al(OH)3 in the presence of dissolved/fixed HA could be reproduced by those for Yb(III)/Eu(III) adsorption in the absence of HA and those for Yb(III)/Eu(III) binding to dissolved HA, respectively. Spectroscopic analyses indicated that the different effects of fixed and dissolved HA on Eu(III)/Yb(III) adsorption were due to different surface speciation with the same surface species, which could be interpreted by the decrease of available sites on fixed HA as compared to those on dissolved HA. This study implied that the effects of HA on the adsorption of Eu(III)/Yb(III) as well as other trivalent lanthanides/actinides in the environment might be overestimated if the differences between dissolved and fixed HA were not considered.

31884. 题目: Fenton oxidation and chromium recovery from tannery wastewater by means of iron-based coated biomass as heterogeneous catalyst in fixed-bed columns
文章编号: N18062562
期刊: Chemical Engineering Journal
作者: Giorgio Vilardi, Javier Miguel Ochando-Pulido, Marco Stoller, Nicola Verdone, Luca Di Palma
更新时间: 2018-06-25
摘要: This work deals with the treatment of a tannery wastewater by a mixed-iron coated olive stone bio-sorbent particles. Olive stones were used as the support to zero-valent iron and magnetite nanoparticles to develop a new material for the removal of chromium, organic matter and total phenols from the wastewater. The optimal operating conditions were determined in batch reactors, after which the process was scaled-up using fixed-bed columns in series. The maximum adsorption capacity for both Cr(III) and Cr(VI), up to 8.37 and 4.29 mg g 1, was attained for a sorbent mass concentration of 4 g L 1, meaning a total chromium adsorption capacity of 12.66 mg g 1, whereas equilibrium contact time was found to be 120 min. The combination of coated olive stones and hydrogen peroxide allowed to develop an heterogeneous Fenton process, that led to reach a COD removal efficiency of 58.4% and a total phenols removal of 59.2%, at H2O2/COD (w/w) = 0.875. In addition, re-use of the coated olive stones by regeneration with NaOH and C2H2O4 solutions after 5 cycles was reported. The column process was successfully described by BDST and Thomas models.

31885. 题目: Pollutant exchange between sewage and sediment in urban sewer systems
文章编号: N18062561
期刊: Chemical Engineering Journal
作者: Xuan Shi, Langtao Sang, Xiaochang C. Wang, Pengkang Jin
更新时间: 2018-06-25
摘要: In this study, the apparent phenomenon of pollutant exchange between sewage and sediment that affected the influent quality of wastewater treatment plants was evaluated by a long-term monitoring in a pilot sewer system. In order to understand the in-depth effect of this phenomenon on water quality in sewer, the pollutant exchange pathways of physical pollutant deposition (PPD), biological transformation adsorption (BTA) and biological transformation release (BTR) were first proposed in this study. And then, the controlled experiments (prohibiting the microbial activity in either biofilms or sediment) were established to quantify the physical and biological pollutant exchange capacity. The results showed that the PPD values of organic, nitrogen and phosphorus pollutants were 144.0 mg/L, 5.15 mg/L and 3.79 mg/L, respectively, and this pathway accounted for over 70% of the pollutant decrease in sewage. It indicated that the PPD was the dominant pollutant exchange pathway in sewers. Meanwhile, the pollutant exchange values in BTR were more than two times of those in BTA (39.2 mg/L > 14.7 mg/L for organic matters; 1.79 mg/L > 0.85 mg/L for nitrogen pollutants; 2.12 mg/L > 1.01 mg/L for phosphorus pollutants). The result indicated that the BTR was the dominant biological reaction which affected the pollutant structures in sewage (especially resulting in the accumulation of volatile fatty acids), and consequently, changed the biodegradability of sewage. Therefore, this study revealed the characteristics of pollutant exchange pathways in sewers and could provide a theoretical basis for the future development of urban sewer systems.

31886. 题目: Dissolved organic nitrogen distribution in differently fertilized paddy soil profiles: Implications for its potential loss
文章编号: N18062560
期刊: Agriculture, Ecosystems & Environment
作者: San’an Nie, Lixia Zhao, Xiumei Lei, Rubab Sarfraz, Shihe Xing
更新时间: 2018-06-25
摘要: Dissolved organic nitrogen (DON) is recognized as an important nitrogen (N) pool in soil N cycling, but its role in the N cycling of paddy soils, which are intensively fertilized, is not fully predicted. In this study, we investigated DON in flooded layer and soil solution along soil profiles with suction cups in fertilized paddy fields. The DON concentration showed a relative decrease in the deeper layer of paddy soil, while free amino acid N (FAA-N) exhibited a drastic increase along with nutrient profiles of soil. In the upper layer (0–20 cm), DON accounted for 54–64% of total dissolved N (TDN), but this value increased up to 63–97% in the deeper layer (40–60 cm). Low concentrations (9.6–15.0 μg L 1) of FAA-N and low percentage of FAA-N/DON (0.1–0.2%) were observed in the upper layer, but higher concentrations (111–307 μg L 1) and increased percentage (8–36%) were examined in the deeper layer. The high percentage of DON/TDN indicated that DON was the predominant N pool in the deeper layer. Concentrations of DON were significantly and positively correlated with organic matter, total N, and electrical conductivity (EC), while negatively related to soil pH. Additionally, capillary porosity, air porosity, bulk density and particle density were also found to be significantly associated with DON. We suggest the DON and FAA in the paddy field could be an important source for N leaching, which is most strongly related with soil nutrient profiles and physical properties. It is estimated that a total loss of 4.0 kg N ha 1 yr 1 is potentially linked to DON in the paddy field, which implied that ca. 3.35% of the applied N fertilizers could be lost via DON.

31887. 题目: Does maize and legume crop residue mulch matter in soil organic carbon sequestration?
文章编号: N18062559
期刊: Agriculture, Ecosystems & Environment
作者: J. Chen, M. Heiling, C. Resch, M. Mbaye, R. Gruber, G. Dercon
更新时间: 2018-06-25
摘要: Soil management techniques, such as mulching, are used to enhance soil organic carbon sequestration. However, we demonstrate that the potential of crop residue mulching to increase soil organic carbon (SOC) sequestration varies by cropping system and soil type in Austrian agricultural soils. Effects of mulch (as harvested crop residues applied at 1.0 t C ha 1) on soil and microbial carbon (C) and nitrogen (N) and soil δ13C were measured in an Austrian Cambisol field experiment with sole maize or vetch or vetch-maize rotation cropping systems after five years with or without mulching to elucidate how SOC is affected. The direct role of mulch on SOC in different soil types was also investigated in a similar greenhouse mesocosm study with controlled moisture using the same Cambisols and an Austrian agricultural Chernozem. Only sole maize cropping in the field experiment resulted in higher SOC with mulching and when legumes were included in a legume-maize rotation SOC did not improve. Mulching in the field experiment only resulted in higher SOC in the top 0–5 cm of soils with sole maize cropping (by 22%) compared to soils without mulch. Although mulch did not increase SOC in vetch-maize rotation, the δ13C of SOC was less negative with mulch indicating larger C contribution from maize than vetch mulch. After four years of annual soybean-maize rotation in the mesocosm experiment, no significant differences in SOC were observed in Cambisols with or without mulch. Again, δ13C of both soil types was less negative with mulching indicating a larger C contribution from maize than soybean mulch. No relationships between microbial biomass C and N and SOC were observed in either experiment and only soil N concentration was positively correlated with SOC. Together these studies indicate that maize can increase SOC when crop residues are applied in Austrian Cambisols but that inclusion of legume production and legume mulch in rotation can mute these benefits.

31888. 题目: Effects of biochar amendment on net greenhouse gas emissions and soil fertility in a double rice cropping system: A 4-year field experiment
文章编号: N18062557
期刊: Agriculture, Ecosystems & Environment
作者: Cong Wang, Jieyun Liu, Jianlin Shen, Dan Chen, Yong Li, Bingshen Jiang, Jinshui Wu
更新时间: 2018-06-25
摘要: A 4-year field experiment was conducted to investigate the effects of biochar amendment on the net greenhouse gas emission (NGHGE), greenhouse gas intensity (GHGI), soil fertility and crop yield in a typical double rice cropping system in the central subtropics of China, from April 2012 to April 2016. Three biochar treatments were studied in this experiment, with application rates of 0, 24 and 48 t ha 1 (named CK, LB and HB, respectively) using straw-derived biochar applied once at the beginning of the experiment. In each treatment, the fluxes of methane (CH4), nitrous oxide (N2O) and soil heterotrophic respiration (Rh) were measured using a static chamber/gas chromatography method. Major soil fertility properties were also determined throughout the experimental period. Biochar amendment was found to persistently decrease annual total CH4 emissions by 20 to 51% in the four years, but increased the annual total N2O emissions and Rh by 150 to 190% and 2 to 19% in the first year and the following three years, respectively. On a 4-year average, biochar addition significantly reduced annual NGHGE and GHGI by 156 to 264% and 159 to 278%, respectively (p < 0.05), with much higher reduction in the first year than those in the following three years (916 to 1911% vs 24 to 51%) due to soil carbon sequestration from biochar addition in the first year. The reduction of NGHGE and GHGI was mainly caused by the decrease of CH4 emissions (71 to 74% contribution), and the increase of soil carbon sequestration (25 to 29% contribution) in biochar treatments. Biochar amendment also significantly and persistently increased soil pH, total organic carbon (TOC), total nitrogen (TSN), and total phosphorus (TSP) by 6 to 14%, 33 to 61%, 11 to 15%, and 9 to 12%, respectively (p < 0.05), in the four years. Significant increases (p < 0.05) of microbial biomass carbon and nitrogen contents were found only in the first year after biochar amendment. Soil pH was also increased significantly (p < 0.05) with biochar amendment, but showed a declining trend in the four years. Annual grain yields for the biochar treatments were enhanced by 1 to 13%, with an average of 4 to 7% in the four years, compared to CK (p = 0.07–0.26). Compared to the LB treatment, the HB treatment significantly decreased average NGHGE and GHGI, and significantly increased average soil pH value and TOC content, but there was no significantly difference in average TSN, TSP, and yield between LB and HB treatments (p < 0.05). The gross margin analysis by considering the profit from rice grain, gain for NGHGE, and cost for biochar indicated that the economical profit for the LB treatment might be higher than that for the CK and HB treatments. Our results suggest that addition of biochar at 24 t ha 1 can be regarded as a consistently effective and economic measure for greenhouse gas emission mitigation, and soil fertility improvement, in the double rice cropping system.

31889. 题目: Evaluating the response of conventional and water harvesting farms to environmental variables using remote sensing
文章编号: N18062556
期刊: Agriculture, Ecosystems & Environment
作者: Brent J. Lloyd, Philip E. Dennison
更新时间: 2018-06-25
摘要: The majority of people in Sub-Saharan Africa (SSA) live in rural communities and practice subsistence farming. Variations in climate and other environmental factors affect the stability of local food production. This instability makes the adoption of efficient farming techniques critical in helping farmers achieve food, income, and livelihood security. Agricultural water conservation techniques called water harvesting are being implemented to increase crop yields in SSA. These techniques have been shown to increase water productivity, nutrients, and organic matter in the soil. This paper uses high-resolution imagery to identify and differentiate between farms using conventional and water-harvesting farm methods. An ordinary least-squares regression model was used to correlate seasonal maximum normalized difference vegetation index (NDVI) values with environmental factors for the different farming methods. The results suggest that water harvesting farm techniques have higher crop yields and are less dependent on precipitation than conventional farming methods. The methodology presented in this paper can be used to map use of water harvesting over large areas and monitor associated differences in productivity.

31890. 题目: Organic management and cover crop species steer soil microbial community structure and functionality along with soil organic matter properties
文章编号: N18062555
期刊: Agriculture, Ecosystems & Environment
作者: Laura B. Martínez-García, Gerard Korthals, Lijbert Brussaard, Helene Bracht J?rgensen, Gerlinde B. De Deyn
更新时间: 2018-06-25
摘要: It is well recognized that organic soil management stimulates bacterial biomass and activity and that including cover crops in the rotation increases soil organic matter (SOM). Yet, to date the relative impact of different cover crop species and organic vs. non-organic soil management on soil bacteria and fungi and on SOM quantity and quality remains to be tested. We used a long-term (10 years) full-factorial field experiment to test the combined effects of organic vs. conventional soil management with different cover crop species (oat or rye) and the legacy effects of seven soil health treatments (SHTs: treatments with compost, chitin, marigold, grass–clover, biofumigation or anaerobic soil disinfestation (ASD), and fallow as control) on microbial community biomass, structure and catabolic activity and on SOM quantity and quality (dissolved organic carbon (DOC), aromaticity and water repellency). Microbial community traits were assessed using PLFA/NLFA analyses and multi-substrate induced respiration. We found that organic soil management enhanced total microbial biomass by increasing bacterial, saprotrophic and arbuscular mycorrhizal fungal biomass; and increased total microbial catabolic activity, associated with maintaining high microbial efficiency (low qCO2). Effects of organic management were amplified by oat as cover crop, which enhanced the abundance of saprotrophic fungi resulting in a higher fungal:bacterial ratio. Total SOM concentration was similar among treatments, however the most easily accessible fraction, i.e. DOC, was higher in organic compared to conventional soils. Also, the aromaticity of the DOC was lower in organic than in conventional systems, which was associated with lower water repellency. There was a legacy effect of SHTs on fungal:bacterial ratio in that chitin and marigold showed higher fungal:bacterial ratio compared to compost, biofumigation and ASD even 6 years after the last application. We conclude that organic soil management enhances the abundance of all microbial groups and their total catabolic activity, associated with a higher concentration and lower aromaticity of dissolved organic matter. These effects can be enlarged by the growth of specific cover crops and the application of certain soil health treatments.

31891. 题目: Why does mineral fertilization increase soil carbon stocks in temperate grasslands?
文章编号: N18062554
期刊: Agriculture, Ecosystems & Environment
作者: Christopher Poeplau, Dorit Zopf, B?rbel Greiner, Rob Geerts, Hein Korvaar, Ulrich Thumm, Axel Don, Arne Heidkamp, Heinz Flessa
更新时间: 2018-06-25
摘要: Globally, grasslands are a major land cover type and store significant amounts of soil organic carbon (SOC). Fertilization with the major plant nutrients nitrogen (N), phosphorus (P), and potassium (K) may affect SOC stocks, e.g., by altering aboveground and belowground plant productivity, species composition, litter composition and decomposition, and microbial metabolism. However, belowground responses to fertilization in grasslands are not fully understood, hampering accurate predictions of SOC dynamics. In this study, seven different long-term grassland fertilization experiments (16–58 years) in Germany and the Netherlands were sampled to determine the effects of mineral fertilization (i.e., N, P, K, PK, and NPK) compared with unfertilized plots (Control) on SOC stocks and root C stocks. Soils were sampled to a depth of 100 cm or to the maximum depth possible. Potential litter decomposition was assessed using Lipton Rooibos and Lipton Green teas as standardized and well-characterized litter materials. In the topsoil (0–30 cm depth), PK, NPK, and NPK+ (increased NPK) fertilization had significant positive effects on SOC stocks, with annual sequestration rates of 0.28, 0.13, and 0.37 Mg ha 1 yr 1, respectively, within an average time span of 34 (PK, NPK) or 20 (NPK+) years. For NPK fertilization, 1.15 kg of N was needed to sequester 1 kg SOC. Increased SOC stocks could not be explained by altered belowground C inputs or decomposition rates, since root C stocks were not affected by fertilization and potential litter decomposition was unchanged. The highly significant increases in dry matter yield with PK and NPK fertilization and resulting higher aboveground C inputs were also unlikely to explain the observed SOC stock changes, since increases were only observed at soil depths >10 cm. However, significantly narrower root C:N ratios were observed for the N (26.9), PK (36.5), NPK (36.8), and NPK+ (33.2) treatments than for the Control (41.8), which may have caused increased microbial C use efficiency, positively affecting SOC storage. The narrower C:N ratios in PK treatments were explained by significantly increased abundance of legumes. We concluded that the carbon footprint of fertilization-induced SOC sequestration needs to be considered when the latter should be accounted for as a climate mitigation measure. Thereby, PK fertilization has much lower CO2 costs than NPK fertilization due to N input via legumes.

31892. 题目: Cell membrane characteristics and microbial population distribution of MBBR and IFAS with different dissolved oxygen concentration
文章编号: N18062553
期刊: Bioresource Technology
作者: Si-jia Ma, Li-li Ding, Hai-dong Hu, Hai-jun Ma, Ke Xu, Hui Huang, Jin-ju Geng, Hong-qiang Ren
更新时间: 2018-06-25
摘要: This paper investigated the influences of different dissolved oxygen (DO) concentration (0.71–1.32, 2.13–3.02 and 4.31–5.16 mg/L) on cell membrane characteristics and microbial population distribution of moving biofilm reactors. Two representative reactors, i.e., moving bed biofilm reactors and integrated fixed-film activated sludge were operated. Results indicated that both DO concentration of 0.71–1.32 mg/L and 4.31–5.16 mg/L could increase membrane lipid mobile fraction (49.4%-67.4%) of the microbes, however, through prompting the synthesis of branched fatty acids and unsaturated fatty acids, respectively. For the biofilms, the abundance of Bacteroidetes decreased and Actinobacteria increased with the increase of DO levels. The lowest EfOM content and the highest microbial diversities (1.14–1.52) was observed at DO of 2.13–3.02 mg/L. Redundancy analysis showed that changes of DO levels could alter cell membrane properties and bacterial community structures, and subsequently significantly influenced effluent organic matter composition of moving biofilm reactors.

31893. 题目: Effect of CaO2 addition on anaerobic digestion of waste activated sludge at different temperatures and the promotion of valuable carbon source production under ambient condition
文章编号: N18062552
期刊: Bioresource Technology
作者: Qian Ping, Xiao Lu, Ming Zheng, Yongmei Li
更新时间: 2018-06-25
摘要: The effect of calcium peroxide (CaO2) addition on anaerobic digestion (AD) of waste activated sludge (WAS) at different temperatures (20 °C, 35 °C, and 55 °C) were investigated. The results show that CaO2 addition had significant positive effect on short-chain fatty acids (SCFAs) production under ambient and mesophilic conditions. Polysaccharides and proteins embedded in extracellular polymeric substances (EPS) were effectively released from inner fraction to outer fraction, and non-biodegradable humic-like substances were decreased while easily biodegradable tryptophan-like proteins increased. These effects were most remarkable under ambient conditions. However, CaO2 addition was unfavorable to thermophilic AD because of high free ammonia concentrations and the accumulation of humic-like substances. Temperature showed a stronger effect than CaO2 on microbial community structure, but CaO2 addition was more effective than temperature in enhancing hydrolytic and acidifying microorganisms. Predictive functional profiling indicated that microbial hydrolysis, metabolism and acidification were promoted by CaO2 under ambient conditions.

31894. 题目: Highly efficient of nitrogen removal from mature landfill leachate using a combined DN-PN-Anammox process with a dual recycling system
文章编号: N18062551
期刊: Bioresource Technology
作者: Xiang Li, Yan Yuan, Fan Wang, Yong Huang, Qing-tan Qiu, Yuan Yi, Zhen Bi
更新时间: 2018-06-25
摘要: An efficient and stable combined denitrification-partial nitrification-Anammox process with a dual recycling system was used to remove nitrogen from mature landfill leachate. After 155 d of operation, the NO3 as the PN-Anammox byproduct was almost treated with biodegradable organic carbon in raw wastewater in a pre-denitrification reactor by external recycling system. When raw landfill leachate with NH4 +-N concentration of 1900 mg/L was treated, an integrated reactor with airlift recycling was combined with the PN and Anammox reactions to efficiently remove NH4 + from the inflow. The total nitrogen concentration of effluent stabilized at 20 mg/L and total nitrogen removal efficiency was 99%. The maximum NO2 production rate in the aerobic zone was 2.2 kg/(m3·d) and the maximum nitrogen removal rate in the anaerobic zone was 21.4 kg/(m3·d). The most common phyla among the nitrification and the Anammox functional bacteria were Nitrosomonas, Candidatus Kuenenia, and Candidatus Brocadia after landfill leachate treatment.

31895. 题目: Strategies and relative mechanisms to attenuate the bioaccumulation and biotoxicity of ceria nanoparticles in wastewater biofilms
文章编号: N18062550
期刊: Bioresource Technology
作者: Yi Xu, Chao Wang, Jun Hou, Peifang Wang, Lingzhan Miao, Guoxiang You
更新时间: 2018-06-25
摘要: Inhibitory effects of ceria nanoparticles (CeO2 NPs) on biofilm were investigated individually and in combination with phosphate (P), ethylene diamine tetraacetic acid (EDTA), humic acid (HA) and citrate (CA) to further explore the toxicity alleviating solutions. Exposure to 20 mg/L CeO2 NPs significantly decreased the performance of biofilm in nutrients removal. Distribution experiments suggested >98% of the CeO2 NPs retained in microbial aggregates, leading to 51.26 μg/L Ce ions dissolution. The dissolved CeIV and its further being reduced to CeIII stimulated the formation of O2 and OH, which increased lipid peroxidation level to 130.93% in biofilms. However, P/EDTA/CA captured or precipitated Ce ions, whereas EDTA/HA/CA shielded NPs-bacteria direct contacts, both disturbing the NPs adsorption, intercepting the redox transition between CeIV and CeIII, reducing the generation of O2 and OH, thus mitigating the toxicity of CeO2 NPs. These results illustrate the main drivers of CeO2 NPs biotoxicity and provide safer-by-design strategies.

31896. 题目: The characteristic evolution of soluble microbial product and its effects on membrane fouling during the development of sponge membrane bioreactor coupled with fiber bundle anoxic bio-filter for treating saline wastewater
文章编号: N18062549
期刊: Bioresource Technology
作者: Zhipeng Li, Weilong Song, Feng Liu, Yi Ding, Hong You, Hengjun Liu, Peishi Qi, Chao Jin
更新时间: 2018-06-25
摘要: Membrane fouling mitigation was observed during the development of novel sponge membrane bioreactor coupled with fiber bundle anoxic bio-filter (AF-MBMBR). Soluble microbial product (SMP) was found to be positively correlated with membrane fouling. To further clarify the mechanism of fouling mitigation, the effects of bio-carriers (sponge and fiber bundles) on characteristics and fouling potential of SMP were investigated. Characterization of SMP implied that as a consequence of employing bio-carriers, tyrosine and tryptophan in SMP significantly decreased, instead relative proportions of humic and fulvic acids increased. Meanwhile, batch filtration tests demonstrated that fouling potential of SMP was significantly alleviated, flux decline caused by filtrating SMP decreased from 84.5% to 60.1%. Further analysis on foulants and filtrate revealed that proteins performed high adhesion propensity on membrane while humic and fulvic acids mainly can pass through the membrane; this finding could well explain the mitigation of SMP fouling potential induced by bio-carriers.

31897. 题目: Effects of different management approaches on soil carbon dynamics in Moso bamboo forest ecosystems
文章编号: N18062548
期刊: CATENA
作者: Chong Li, Yongjun Shi, Guomo Zhou, Yufeng Zhou, Lin Xu, Liang Tong, Xiang Liu
更新时间: 2018-06-25
摘要: Moso bamboo (Phyllostachys pubescens) is a very important forest resource in subtropical China, and it has excellent carbon sequestration potential, and can play an important role in mitigating climate change. The international community has gradually recognized the benefits of Reducing Emissions from Deforestation and Forest Degradation (REDD+) forest carbon sequestration mechanisms, and the areas available for the development of forest carbon sinks have greatly expanded. Therefore, in this study, we use a two-factor randomized complete block design in which fertilization rate and harvesting intensity were selected to investigate the changes in soil organic carbon (SOC) concentration and carbon (C) storage from 2010 to 2016. With 3k orthogonal method, a factorial analysis with 3 levels of fertilization (high (1800), medium (900) and low (0 kg ha 1 year 1)) and 3 levels of harvesting intensity (high (100%), medium (50%) and low (0%) cutting of the bamboo of 4–5 years old) has been taken. Our results show that fertilization, harvesting, and the fertilization × harvesting interaction had significant effects on SOC concentration changes, but not on C storage after six years of management. Only the interaction between high fertilization and high intensity harvesting, which we called the intensive management model, caused a decrease of 4.48 Mg C ha 1 in the 0–50 cm soil layer C storage. The interaction between no fertilization and low intensity harvesting, which we called the traditional management model, increased soil carbon C by 7.90 Mg C ha 1. The optimized management model of high fertilization and medium intensity harvesting increased soil C the most; by 59.94 Mg C ha 1, which is 2.36 times larger than that of the intensive management model, and 1.86 times larger than that of the traditional management model. The results clearly reveal that the soil carbon pools in Moso bamboo forest have a great carbon sequestration potential under the optimized management model.

31898. 题目: Effects of snowfall depth on soil physical–chemical properties and soil microbial biomass in moss–dominated crusts in the Gurbantunggut Desert, Northern China
文章编号: N18062547
期刊: CATENA
作者: Ruiming Zhao, Rong Hui, Lichao Liu, Min Xie, Lizhe An
更新时间: 2018-06-25
摘要: Winter snowfall is an important source of moisture that may influence the growth and development of biological soil crusts (BSCs) in temperate desert regions of China. Yet there is still limited empirical knowledge about the effect of snowfall on BSCs. In this study, moss crusts from the Gurbantunggut Desert were exposed to five snow depths to evaluate how snowfall affected the physical–chemical properties (pH; electric conductivity, EC; soil organic carbon, SOC; total nitrogen, TN; available nitrogen, AN; available phosphorus, AP; available potassium, AK) and microbial biomass (soil microbial biomass carbon, SMBC; soil microbial biomass nitrogen, SMBN; soil microbial biomass phosphorus, SMBP) of soil in the BSCs, before (in October 2016: representing three consecutive years of snow manipulation) and after winter (in April 2017). Results showed that the soil water content increased significantly as snowfall depth increased (p < 0.05) in October 2016 and April 2017. Most of the soil physical–chemical features (EC, SOC, TN, AN, AP, and AK) and microbial biomass (SMBC and SMBN) showed an increase with an increase of snowfall depth after three consecutive years of snow manipulation. Moreover, for most experimental treatments, after a winter of melting snow (in April 2017) most of the soil properties were significantly higher (p < 0.05) than found in October 2016. Together, these results showed that the dynamics of soil nutrients and microbial biomass in moss BSCs were affected by snowfall depth in Gurbantunggut Desert. Different snowfall depths can have different effects on the dynamics of soil nutrients and microbial biomass of moss crusts, an impact that may alter the future growth and development of BSCs. Thus, we suggest that the potential influence of snowfall depth on soil nutrients and microbial biomass dynamics in BSCs require consideration when discussing the effects of moisture on ecological functions of BSCs in arid and semi–arid regions.

31899. 题目: Geochemical fingerprint of insoluble material in soil on different limestone formations
文章编号: N18062546
期刊: CATENA
作者: Nina Zupan?i?, Rok Turni?ki, Milo? Miler, Helena Gr?man
更新时间: 2018-06-25
摘要: In the Karst region near Diva a, Slovenia, soils are developed on the limestone of three geological formations: Se ana, Lipica, and Liburnian. In each formation, six soil profiles were dug, limestone insoluble residua was obtained, and in Liburnian Formation interbedded material and material filling fractures and cavities was sampled. All soils have silty clay and silty-clayey loam texture, pH levels in the range 4.5–7.0, high organic matter content and saturation with basic cations over 50%. However, soils on the Se ana Formation are deeper and more evolved, and besides as Rendzic Phaeozem classify also as Eutric Cambisol. Their insoluble residuum is richest in mineral part. The profiles on the Lipica Formation are a Rendzic Phaeozem, and the shallowest soils on the Liburnian Formation are either a Rendzic Phaeozem or a Rendzic Leptosol. Additionally, the soils formed over the Lipica Formation are characterised by a greater portion of the small rock fragments (<200 g), due to its paleo-karstification. The insoluble residuum of all three formations is rich in organic matter and fine grained. The general soil chemistry is in accordance with highly weathered upper crustal material and, compared to insoluble residua indicates the contribution of material from an additional source. The analysis of variance demonstrated differences in redox-sensitive elements (Cr, Mo, Ni, U, V, and Y) between formations, which are inherited by the insoluble residua. The insoluble residua contributed material and left a specific geochemical fingerprint in the observed soils, but regarding texture and general geochemistry, non-carbonate material must have been added. The material that fills karst forms inside the limestone profile is similar to the soils, but not identical. Other interbedded and probably also eolian material contributed to the final mass.

31900. 题目: Greenhouse gas inventories: Deriving soil organic carbon change factors and assessing soil depth relevance in Argentinean Semiarid Chaco
文章编号: N18062545
期刊: CATENA
作者: Sebastián Horacio Villarino, Guillermo Alberto Studdert, Pedro Laterra
更新时间: 2018-06-25
摘要: Soil organic carbon (SOC) is the main terrestrial carbon (C) reservoir. Land use change has depleted SOC stocks and released large amounts of C dioxide (CO2). Thus, the development of reliable tools for SOC stock monitoring at large scale is fundamental to face climate change. Argentinean Semiarid Chaco (ASC) is a deforestation hotspot, but CO2 emissions from soil has been barely assessed. Deforested area was converted into cropland or grassland. We used empirical data to model SOC stocks under native forest (SOCref) and the RothC model to estimate SOC stock change factors under cropland (Fc) and grasslands (Fg) in the ASC. These SOCref's and stock change factors were applied in a Tier 2 (T2) C inventory, following the Intergovernmental Panel on Climate Change (IPCC) proposal. We used SOC vertical distribution models to estimate SOC stock at 0–100 cm soil depth from estimated SOC stocks at 0–30 cm, the default soil depth of IPCC C inventory method. The T2 was run for 1976 through 2012 and under three hypothetical land use change scenarios for 2012 through 2032. The scenarios were: i) land use change ceases, ii) land use change rate is the half of 1996–2012 land use change rate, and iii) land use change rate remains as in 1996–2012. Estimated average SOCref stock at 0–30 cm soil depth was 40 Mg C ha 1 and varied between 35 and 51 Mg C ha 1. Cropland was the main fate of deforested area and the land use with lower SOC stocks. Stock change factors and SOC stocks estimated with T2 were within the range of the empirical data reported in the ASC. However, research about SOC dynamics and land use change is incipient in the ASC and more empirical information is needed to validate T2 estimations. Deforestation in the ASC leads to high CO2 emissions from soil and the only scenario in which those emissions would be reduced is with deforestation cessation. Soil depth considered in greenhouse gas inventories is 0–30 cm, and this strongly underestimates CO2 emissions. We demonstrated that this limitation could be overcome by using SOC vertical distribution models to estimate deep SOC stock (up to 1 m) from estimated surface SOC stock. Hence, these models could be used to improve CO2 estimations from SOC inventories.