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Parkland trees on smallholder farms ameliorate soil physical-chemical properties in the semi-arid area of Tigray,Ethiopia
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作者 Selam LJALEM Emiru BIRHANE +1 位作者 Kassa TEKA Daniel H BERHE 《Journal of Arid Land》 SCIE CSCD 2024年第1期1-13,共13页
Proposed agroforestry options should begin with the species that farmers are most familiar with,which would be the native multipurpose trees that have evolved under smallholder farms and socioeconomic conditions.The A... Proposed agroforestry options should begin with the species that farmers are most familiar with,which would be the native multipurpose trees that have evolved under smallholder farms and socioeconomic conditions.The African birch(Anogeissus leiocarpa(DC.)Guill.&Perr.)and pink jacaranda(Stereospermum kunthianum Cham.)trees are the dominant species in the agroforestry parkland system in the drylands of Tigray,Ethiopia.Smallholder farmers highly value these trees for their multifunctional uses including timber,firewood,charcoal,medicine,etc.These trees also could improve soil fertility.However,the amount of soil physical and chemical properties enhanced by the two species must be determined to maintain the sustainable conservation of the species in the parklands and to scale up to similar agroecological systems.Hence,we selected twelve isolated trees,six from each species that had similar dendrometric characteristics and were growing in similar environmental conditions.We divided the canopy cover of each tree into three radial distances:mid-canopy,canopy edge,and canopy gap(control).At each distance,we took soil samples from three different depths.We collected 216 soil samples(half disturbed and the other half undisturbed)from each canopy position and soil depth.Bulk density(BD),soil moisture content(SMC),soil organic carbon(SOC),total nitrogen(TN),available phosphorus(AP),available potassium(AK),p H,electrical conductivity(EC),and cation exchange capacity(CEC)were analysed.Results revealed that soil physical and chemical properties significantly improved except for soil texture and EC under both species,CEC under A.leiocarpus,and soil p H under S.kunthianum,all the studied soils were improved under both species canopy as compared with canopy gap.SMC,TN,AP,and AK under canopy of these trees were respectively 24.1%,11.1%,55.0%,and 9.3% higher than those soils under control.The two parkland agroforestry species significantly enhanced soil fertility near the canopy of topsoil through improving soil physical and chemical properties.These two species were recommended in the drylands with similar agro-ecological systems. 展开更多
关键词 AGROFORESTRY bulk density carbon stock dispersed tree soil texture tree canopy
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The microbial community,nutrient supply and crop yields differ along a potassium fertilizer gradient under wheat-maize double-cropping systems
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作者 Zeli Li Fuli Fang +10 位作者 Liang Wu Feng Gao Mingyang Li Benhang Li Kaidi Wu Xiaomin Hu Shuo Wang Zhanbo Wei Qi Chen Min Zhang Zhiguang Liu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第10期3592-3609,共18页
Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In thi... Soil microorganisms play critical roles in ecosystem function.However,the relative impact of the potassium(K)fertilizer gradient on the microbial community in wheat-maize double-cropping systems remains unclear.In this long-term field experiment(2008-2019),we researched bacterial and fungal diversity,composition,and community assemblage in the soil along a K fertilizer gradient in the wheat season(K0,no K fertilizer;K1,45 kg ha^(-1) K_(2)O;K_(2),90 kg ha^(-1)K_(2)O;K3,135 kg ha^(-1)K_(2)O)and in the maize season(K0,no K fertilizer;K_(1),150 kg ha^(-1) K_(2)O;K_(2),300 kg ha^(-1)K_(2)O;K_(3),450 kg ha^(-1)K_(2)O)using bacterial 16S rRNA and fungal internally transcribed spacer(ITS)data.We observed that environmental variables,such as mean annual soil temperature(MAT)and precipitation,available K,ammonium,nitrate,and organic matter,impacted the soil bacterial and fungal communities,and their impacts varied with fertilizer treatments and crop species.Furthermore,the relative abundance of bacteria involved in soil nutrient transformation(phylum Actinobacteria and class Alphaproteobacteria)in the wheat season was significantly increased compared to the maize season,and the optimal K fertilizer dosage(K2 treatment)boosted the relative bacterial abundance of soil nutrient transformation(genus Lactobacillus)and soil denitrification(phylum Proteobacteria)bacteria in the wheat season.The abundance of the soil bacterial community promoting root growth and nutrient absorption(genus Herbaspirillum)in the maize season was improved compared to the wheat season,and the K2 treatment enhanced the bacterial abundance of soil nutrient transformation(genus MND1)and soil nitrogen cycling(genus Nitrospira)genera in the maize season.The results indicated that the bacterial and fungal communities in the double-cropping system exhibited variable sensitivities and assembly mechanisms along a K fertilizer gradient,and microhabitats explained the largest amount of the variation in crop yields,and improved wheat?maize yields by 11.2-22.6 and 9.2-23.8%with K addition,respectively.These modes are shaped contemporaneously by the different meteorological factors and soil nutrient changes in the K fertilizer gradients. 展开更多
关键词 potassium fertilizer gradient microbial community wheat-maize double cropping climate change yield
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Arbuscular mycorrhizal fungi improve biomass, photosynthesis, and water use efficiency of Opuntia ficus-indica (L.) Miller under different water levels
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作者 Teame G KEBEDE Emiru BIRHANE +1 位作者 Kiros-Meles AYIMUT Yemane G EGZIABHER 《Journal of Arid Land》 SCIE CSCD 2023年第8期975-988,共14页
Opuntia ficus-indica(L.)Miller is a CAM(crassulacean acid metabolism)plant with an extraordinary capacity to adapt to drought stress by its ability to fix atmospheric CO_(2) at nighttime,store a significant amount of ... Opuntia ficus-indica(L.)Miller is a CAM(crassulacean acid metabolism)plant with an extraordinary capacity to adapt to drought stress by its ability to fix atmospheric CO_(2) at nighttime,store a significant amount of water in cladodes,and reduce root growth.Plants that grow in moisture-stress conditions with thick and less fine root hairs have a strong symbiosis with arbuscular mycorrhizal fungi(AMF)to adapt to drought stress.Water stress can limit plant growth and biomass production,which can be rehabilitated by AMF association through improved physiological performance.The objective of this study was to investigate the effects of AMF inoculations and variable soil water levels on the biomass,photosynthesis,and water use efficiency of the spiny and spineless O.ficus-indica.The experiment was conducted in a greenhouse with a full factorial experiment using O.ficus-indica type(spiny or spineless),AMF(presence or absence),and four soil water available(SWA)treatments through seven replications.Water treatments applied were 0%–25%SWA(T1),25%–50%SWA(T2),50%–75%SWA(T3),and 75%–100%SWA(T4).Drought stress reduced biomass and cladode growth,while AMF colonization significantly increased the biomass production with significant changes in the physiological performance of O.ficus-indica.AMF presence significantly increased biomass of both O.ficus-indica plant types through improved growth,photosynthetic water use efficiency,and photosynthesis.The presence of spines on the surface of cladodes significantly reduced the rate of photosynthesis and photosynthetic water use efficiency.Net photosynthesis,photosynthetic water use efficiency,transpiration,and stomatal conductance rate significantly decreased with increased drought stress.Under drought stress,some planted mother cladodes with the absence of AMF have not established daughter cladodes,whereas AMF-inoculated mother cladodes fully established daughter cladodes.AMF root colonization significantly increased with the decrease of SWA.AMF caused an increase in biomass production,increased tolerance to drought stress,and improved photosynthesis and water use efficiency performance of O.ficus-indica.The potential of O.ficus-indica to adapt to drought stress is controlled by the morpho-physiological performance related to AMF association. 展开更多
关键词 BIOMASS cactus pear cladode growth PHOTOSYNTHESIS water stress water use efficiency
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Urban Land Use Change Detection Using Multisensor Satellite Images 被引量:5
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作者 DENG Jin-Song WANG Ke +1 位作者 LI Jun DENG Yan-Hua 《Pedosphere》 SCIE CAS CSCD 2009年第1期96-103,共8页
Due to inappropriate planning and management, accelerated urban growth and tremendous loss in land, especially cropland, have become a great challenge for sustainable urban development in China, especially in develope... Due to inappropriate planning and management, accelerated urban growth and tremendous loss in land, especially cropland, have become a great challenge for sustainable urban development in China, especially in developed urban area in the coastal regions; therefore, there is an urgent need to effectively detect and monitor the land use changes and provide accurate and timely information for planning and management. In this study a method combining principal component analysis (PCA) of multisensor satellite images from SPOT (systeme pour l'observation de la terre or earth observation satellite)-5 multispectral (XS) and Landsat-7 enhanced thematic mapper (ETM) panchromatic (PAN) data, and supervised classification was used to detect and analyze the dynamics of land use changes in the city proper of Hangzhou. The overall accuracy of the land use change detection was 90.67% and Kappa index was 0.89. The results indicated that there was a considerable land use change (10.03% of the total area) in the study area from 2001 to 2003, with three major types of land use conversions: from cropland into built-up land, construction site, and water area (fish pond). Changes from orchard land into built-up land were also detected. The method described in this study is feasible and useful for detecting rapid land use change in the urban area. 展开更多
关键词 change detection land use multisensor satellite image principal component analysis (PCA) urban area
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Simulation on release of heavy metals Cd and Pb in sediments 被引量:5
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作者 Hong-jie YAN He-yang ZHANG +4 位作者 Ya-jun SHI Ping ZHOU Huan LI Dong-ling WU Liu LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第1期277-287,共11页
The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show tha... The re-release process and the release rate of heavy metals,cadmium and plumbum,which are rich in sediments of a certain water area,were investigated using a combined experimental and numerical method.Results show that the release law of Cd and Pb in sediments is divided into two stages:rapid release and dynamic equilibrium,which is in great agreement with the pseudo second-order kinetic equation with a correlation coefficient R2 above 0.99.As the flow velocity accelerates,the release rate of heavy metals increases.The analysis results indicate that the water quality in the area can exceed the surface water Class V standard less than 3 h,and all but one of the relative deviations between the simulation value and the field survey result are within±10%. 展开更多
关键词 SEDIMENT heavy metal pollution re-release rate numerical simulation
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Local Variability in Temperature, Humidity and Radiation in the BaekduDaegan Mountain Protected Area of Korea 被引量:5
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作者 CHAE Heemun LEE Hyunju +4 位作者 LEE Sangsin CHEONG Yukyong UM Gijeung MARK Bryan PATRICK Nathan 《Journal of Mountain Science》 SCIE CSCD 2012年第5期613-627,共15页
A novel embedded sensor network records changes in key climatic-environmental variables over a range of altitude in the BaekduDaegan Mountain (BDM) of Gangwon Province in Korea, a protected mountain region with uniq... A novel embedded sensor network records changes in key climatic-environmental variables over a range of altitude in the BaekduDaegan Mountain (BDM) of Gangwon Province in Korea, a protected mountain region with unique biodiversity undergoing climate change research. The investigated area is subdivided into three horizontal north-south study areas. Three variables, temperature (T, °C), relative humidity (RH, %), and light intensity (LI, lumens m-2, or lux, lx), have been continuously measured at hourly intervals from June, 2olo to September, 2011 using HOBO H8 devices at lO fixed study sites. These hourly observations are aggregated to monthly, seasonal and annual mean values, and results are summarized to inaugurate a long-term climate change investigation. A region wide T difference in accordance with altitude, or lapse rate, over the interval is calculated as o.4°C l00 m-1. T lapse rates change seasonally, with winter lapse rates being greater than those of summer. RH is elevated in summer compared to other seasons. LI within forestland is lower during summer and higher during other seasons. The obtained results could closely relate to the vegetation type and structure and the terrain state since data loggers were located in forestland. 展开更多
关键词 Embedded sensors Temperature lapserates Relative humidity Light intensity FOREST Climate change BaekduDaegan Mountain
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Extraction chromatography–electrodeposition(EC–ED) process to recover palladium from high-level liquid waste 被引量:3
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作者 Qing Zou Shuai Gu +3 位作者 Rui-Qin Liu Shun-Yan Ning Yan-Liang Chen Yue-Zhou Wei 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第12期209-219,共11页
The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatogra... The extraction chromatography–electrodeposition(EC–ED) process was proposed for the quantitative recovery of palladium from high-level liquid waste(HLLW) in this study. The process coupled the extraction chromatography method to obtain the decontamination of Pd(II) from HLLW with the electrochemical method to recover metallic palladium from the concentrated solution.Separation of Pd(II) from a nitric acid medium by extraction chromatography using iso Bu-BTP/SiO_2-P adsorbent and the electrochemical behavior of Pd(II) in nitric acid solution in the presence of thiourea(TU) were investigated.iso Bu-BTP/SiO_2-P exhibited a high selectivity for Pd(II)over other fission products(FPs), and Pd(II) could be desorbed by TU from loaded BTP/SiO_2-P. The adsorbent performed good stability against HNO_3 because the adsorption performance kept Pd(II) after extended contact with HNO_3 solution. The column experiment achieved the separation of Pd(II) from simulated HLLW successfully.The electrochemical behavior of Pd(II) in palladium desorption solution containing TU and nitric acid was investigated at a platinum electrode by cyclic voltammetry. A weak reduction wave at-0.4 V was due to the reduction in Pd(II) to Pd(0), and the deposition process wasirreversible. In electrowinning experiments, a maximum of92% palladium could be obtained. 展开更多
关键词 PALLADIUM HLLW Extraction CHROMATOGRAPHY ELECTRODEPOSITION BTP/SiO2-P THIOUREA
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Comparative study on chalcopyrite bioleaching with assistance of different carbon materials by mixed moderate thermophiles 被引量:6
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作者 Ping ZHU Xue-duan LIU +5 位作者 Ai-jia CHEN Hong-wei LIU Hua-qun YIN Guan-zhou QIU Xiao-dong HAO Yi-li LIANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第6期1294-1303,共10页
The catalysis of four carbon materials including artificial graphite(AG), carbon black(CB), activated carbon(AC) and carbon nanotube(CN) on chalcopyrite bioleaching by mixed moderate thermophiles was comparatively inv... The catalysis of four carbon materials including artificial graphite(AG), carbon black(CB), activated carbon(AC) and carbon nanotube(CN) on chalcopyrite bioleaching by mixed moderate thermophiles was comparatively investigated. In AC and AG added bioleaching groups, low solution pH and suitable redox potential values, high total iron and ferric iron concentrations, and large number of adsorbed bacteria were obtained, resulting in high copper extractions. CB and CN inhibited the growth of bioleaching bacteria and led to the low bioleaching efficiency.X-ray diffraction analysis showed that jarosite and sulfur film were the main components of passivation layer with the addition of AG and AC,but did not hinder the dissolution of chalcopyrite. Microbial community structures of free and attached cells in AC and AG added groups changed dramatically compared with mixed moderate thermophiles. The sulfur-oxidizing bacteria of A. caldus S1 strain dominated the microbial community(93%-98%) at the end of bioleaching.The iron-oxidizing bacteria of L.ferriphilum YSK only accounted for low percentage(1%-2%). 展开更多
关键词 CHALCOPYRITE leaching carbon material mixed moderate thermophiles microbial community structure
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Effects of soil drought stress on photosynthetic gas exchange traits and chlorophyll fluorescence in Forsythia suspensa 被引量:10
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作者 Ying Lang Ming Wang +1 位作者 Jiangbao Xia Qiankun Zhao 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第1期45-53,共9页
To clarify the changes in plant photosynthesis and mechanisms underlying those responses to gradually increasing soil drought stress and reveal quantitative relationships between photosynthesis and soil moisture,soil ... To clarify the changes in plant photosynthesis and mechanisms underlying those responses to gradually increasing soil drought stress and reveal quantitative relationships between photosynthesis and soil moisture,soil water conditions were controlled in greenhouse pot experiments using 2-year-old seedlings of Forsythia suspensa(Thunb.) Vahl. Photosynthetic gas exchange and chlorophyll fluorescence variables were measured and analyzed under 13 gradients of soil water content. Net photosynthetic rate(PN), stomatal conductance(gs), and water-use efficiency(WUE) in the seedlings exhibited a clear threshold response to the relative soil water content(RSWC). The highest PNand WUEoccurred at RSWCof51.84 and 64.10%, respectively. Both PNand WUEwere higher than the average levels at 39.79% B RSWCB 73.04%. When RSWCdecreased from 51.84 to 37.52%,PN, gs, and the intercellular CO2 concentration(Ci)markedly decreased with increasing drought stress; the corresponding stomatal limitation(Ls) substantially increased, and nonphotochemical quenching(NPQ) also tended to increase, indicating that within this range of soil water content, excessive excitation energy was dispersed from photosystem II(PSII) in the form of heat, and the reduction in PNwas primarily due to stomatal limitation.While RSWCdecreased below 37.52%, there were significant decreases in the maximal quantum yield of PSII photochemistry(Fv/Fm) and the effective quantum yield of PSII photochemistry(UPSII), photochemical quenching(qP), and NPQ; in contrast, minimal fluorescence yield of the dark-adapted state(F0) increased markedly. Thus,the major limiting factor for the PNreduction changed to a nonstomatal limitation due to PSII damage. Therefore, an RSWCof 37.52% is the maximum allowable water deficit for the normal growth of seedlings of F. suspensa, and a water content lower than this level should be avoided in field soil water management. Water contents should be maintained in the range of 39.79% B RSWCB 73.04% to ensure normal function of the photosynthetic apparatus and high levels of photosynthesis and efficiency in F.suspensa. 展开更多
关键词 Chlorophyll fluorescence Gas exchange Photosynthetic rate Soil water deficit Stomatal mechanism Water-use efficiency
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Increased BnaMFT-transcript level is associated with secondary dormancy in oilseed rape (Brassica napus L.) 被引量:3
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作者 LIU Lei FAN Wen-qi +6 位作者 LIU Fu-xia YI Xin TANG Tang ZHOU Ying TANG Zi-wei CHEN Guimin ZHAO Xiang-xiang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第6期1565-1576,共12页
Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,re... Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,reduced quality and biosafety issues.However,informati on regarding the molecular mecha nism un derlyi ng sec on dary dormancy is limited.The MOTHER OF FT AND TFL1(MFT)gene,which is evolutionarily conserved in the plant kingdom,acts in a complex gene network in the seed dormancy or germination processes.In this study,we identified four B.napus genes that share high homology with AtMFT,named as BnaMFT.Analyses of c/s-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements,and various stress-and hormone-responsive elements.Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed,with peaks at 35-42 days after pollination.BnaMFTs were not sufficient for primary dormancy;however,they were significantly enhanced by secondary dormancy induction with PEG6000 treatment.Moreover,BnaMFTtranscripts were elevated by treatment with abscisic acid(ABA),which is known to be accumulated duri ng sec on dary dorma ncy.These results collectively suggest that increased BnaMFT tra nscription levels are associated with sec on dary dorma ncy inducti on in an ABA-depe ndent mariner in B.napus. 展开更多
关键词 BRASSICA NAPUS DELAY OF GERMINATION 1(DOG7) MFT primary DORMANCY secondary DORMANCY
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Utilizing partial least square and support vector machine for TBM penetration rate prediction in hard rock conditions 被引量:11
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作者 高栗 李夕兵 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期290-295,共6页
Rate of penetration(ROP) of a tunnel boring machine(TBM) in a rock environment is generally a key parameter for the successful accomplishment of a tunneling project. The objectives of this work are to compare the accu... Rate of penetration(ROP) of a tunnel boring machine(TBM) in a rock environment is generally a key parameter for the successful accomplishment of a tunneling project. The objectives of this work are to compare the accuracy of prediction models employing partial least squares(PLS) regression and support vector machine(SVM) regression technique for modeling the penetration rate of TBM. To develop the proposed models, the database that is composed of intact rock properties including uniaxial compressive strength(UCS), Brazilian tensile strength(BTS), and peak slope index(PSI), and also rock mass properties including distance between planes of weakness(DPW) and the alpha angle(α) are input as dependent variables and the measured ROP is chosen as an independent variable. Two hundred sets of data are collected from Queens Water Tunnel and Karaj-Tehran water transfer tunnel TBM project. The accuracy of the prediction models is measured by the coefficient of determination(R2) and root mean squares error(RMSE) between predicted and observed yield employing 10-fold cross-validation schemes. The R2 and RMSE of prediction are 0.8183 and 0.1807 for SVMR method, and 0.9999 and 0.0011 for PLS method, respectively. Comparison between the values of statistical parameters reveals the superiority of the PLSR model over SVMR one. 展开更多
关键词 tunnel boring machine(TBM) performance prediction rate of penetration(ROP) support vector machine(SVM) partial least squares(PLS)
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Responses of bacterial community to potential heap construction methods of fine-grained copper tailings in column bioleaching system 被引量:2
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作者 Xiao-dong HAO Xue-duan LIU +8 位作者 Ping ZHU Yi-li LIANG Guan-zhou QIU Hong-qing MA Yan LIU Qian-jin LIU Li-ying REN Emmanuel Konadu SARKODIE Hong-wei LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第6期1796-1805,共10页
The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM)... The column bioleaching of copper flotation tailings was comparatively investigated using layered heap construction method(LM),agglomerate heap construction method(AM),and pellets-sintering heap construction method(PM).The bacterial communities of free,attached,weakly-attached,and strongly-attached microbes in the later bioleaching stage were investigated.In AM group,the addition of lump sulphide ore resulted in the low leachate pH,high ferric iron concentration,and rapid microbial adsorption,which obtained the maximum copper extraction(60.1%)compared with LM(54.6%)and PM(43.9%)groups.The relative abundance of dominant genera and microbial communities of different microbiota underwent changes in three heap construction methods.The alpha-diversity indexes of attached,weakly-attached,and strongly-attached microbes were different,while no significant change was observed in free bacteria.The variation of whole bacterial community was significantly associated with solution pH,total iron,and ferric iron concentrations.Pearson correlation analysis and partial least square path model both indicated that attached bacteria made larger contribution to the copper extraction of tailings. 展开更多
关键词 fine-grained tailings column bioleaching heap construction method free and attached bacteria microbial diversity
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^(15)N Isotope Techniques for Estimating Effects of Urea-N Fertilizer Application Rate on Yields and Nutrient Contents of Pakchoi Cabbage and Asparagus Lettuce and Nitrogen Utilization Efficiency 被引量:1
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作者 LIAO Yu-lin ZHENG Sheng-xian +2 位作者 RONG Xiang-min LIU Qiang FAN Mei-rong 《Agricultural Science & Technology》 CAS 2010年第7期151-156,共6页
A pot experiment combined with15N isotope techniques was conducted to evaluate effects of the varying rates of urea-N fertilizer application on yields,quality,and nitrogen use efficiency (NUE) of pakchoi cabbage (Bras... A pot experiment combined with15N isotope techniques was conducted to evaluate effects of the varying rates of urea-N fertilizer application on yields,quality,and nitrogen use efficiency (NUE) of pakchoi cabbage (Brassica chinensis L.) and asparagus lettuce (Lactuca saiva L.).15N-labbled urea (5.3515N atom %) was added to pots with 6.5 kg soil of 0.14,0.18,0.21,0.25,and 0.29 g N/kg soil,and applied in two splits:60 percent as basal dressing in the mixture and 40 percent as topdressing.The fresh yields of two vegetable species increased with the increasing input of urea-N,but there was a significant quadratic relationship between the dose of urea-N fertilizer application and the fresh yields.When the dosage of urea-N fertilizer reached a certain value,nitrate readily accumulated in the two kinds of plants due to the decrease in NR activity; furthermore,there was a linear negative correlation between nitrate content and NR activity.With the increasing input of urea-N,ascorbic acid and soluble sugar initially increased,declined after a while,and crude fiber rapidly decreased too.Total absorbed N (TAN),N derived from fertilizer (Ndff),and N derived from soil (Ndfs) increased,and the ratio of Ndff and TAN also increased,but the ratio of Ndfs and TAN as well as NUE of urea-N fertilizer decreased with the increasing input of urea-N.These results suggested that the increasing application of labeled N fertilizer led to the increase in unlabeled N (namely,Ndfs) presumably due to "added nitrogen interaction" (ANI),the decease in NUE of urea-N fertilizer may be due to excess fertilization beyond the levels of plant requirements and the ANI,and the decrease in the two vegetable yields with the increasing addition of urea-N possibly because the excess accumulation of nitrate reached a toxic level. 展开更多
关键词 ^15N N utilization ratio Pot experiment Vegetable Nutrition quality Yield
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Phthalate Esters Biodegradation by Fusarium Oxysporum in Vegetable Soil 被引量:1
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作者 LV Hui-ying LI Gao-yang +3 位作者 FANG Zhi-hui ZHANG Fan LIANG Zeng-enni SHAN Yang 《Agricultural Science & Technology》 CAS 2018年第3期52-57,共6页
In this research, soil samples were frst polluted with 6 PAEs (i.e. DMP, DEP, DIBP, DBP, DEHP, and BBP) at 3 different concentration gradients (0, 10, and 20 mg/kg) and then treated with a highly-efficient degrada... In this research, soil samples were frst polluted with 6 PAEs (i.e. DMP, DEP, DIBP, DBP, DEHP, and BBP) at 3 different concentration gradients (0, 10, and 20 mg/kg) and then treated with a highly-efficient degradation fungus, Fusarium oxysporum (PO-Yi), to investigate the biodegradation of PAEs in pepper and eggplant soil. The findings revealed that PO-Yi can accelerate the degradation of PAEs in vegetable soils including pepper and eggplant soil to varying degrees. The highest absolute degradation rate (up to 39.5%) was observed in DEP-treated soils at the high pollution level (20 mg/kg), which was 14.2% higher than that at the middle pollution level (10 mg/kg). The degradation effect in the pepper soil was superior to that in the eggplant soil. Vegetable soil, either pepper soil or eggplant soil, which was polluted by various PAEs at different pollution gradients and then treated with PO-Yi fungus presented good bioremediation results. In the pepper and eggplant soil, 76.8% and 63.1% of the PAEs with a total volume of 60 mg/kg were degraded within 30 d respectively. PO-Yi, indigenous microorganisms, and the vegetables, i.e. pepper and eggplant had good synergistic effects on the degradation of compound PAEs in PAE-polluted pot soil. 展开更多
关键词 Fusarium oxysporum (PO-Yi) PHTHALATES SOIL BIODEGRADATION Pot experiment
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论主流诗学对翻译的影响——以王科一的《傲慢与偏见》中译本为例
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作者 杨帆 YANG Fan 《中南林业科技大学学报(社会科学版)》 2013年第3期155-157,共3页
翻译是两种语言文化之间的交流与融合,原著的文学光芒与艺术生命想要在目的语境中得以再现和延续,迻译过程势必受到译入语文化的影响。基于勒菲弗尔操纵论中诗学的相关理论,通过对王科一的《傲慢与偏见》中译本研究,探讨其文本翻译时译... 翻译是两种语言文化之间的交流与融合,原著的文学光芒与艺术生命想要在目的语境中得以再现和延续,迻译过程势必受到译入语文化的影响。基于勒菲弗尔操纵论中诗学的相关理论,通过对王科一的《傲慢与偏见》中译本研究,探讨其文本翻译时译入语社会的主流诗学,从诗学的两类表现形式——措辞和句式——两个方面对译本进行分析,证实在一定的社会文化语境中,为保证译介活动顺利进行,译者受主流诗学观的影响,改写操控原文,使译作符合译入语主流诗学的追求和主张。 展开更多
关键词 主流诗学 操纵 傲慢与偏见 措辞 句式
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Effect of nitrogen and phosphorus addition on leaf nutrient concentrations and nutrient resorption efficiency of two dominant alpine grass species 被引量:1
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作者 LIU Yalan LI Lei +2 位作者 LI Xiangyi YUE Zewei LIU Bo 《Journal of Arid Land》 SCIE CSCD 2021年第10期1041-1053,共13页
Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to ... Nitrogen(N)and phosphorus(P)are two essential nutrients that determine plant growth and many nutrient cycling processes.Increasing N and P deposition is an important driver of ecosystem changes.However,in contrast to numerous studies about the impacts of nutrient addition on forests and temperate grasslands,how plant foliar stoichiometry and nutrient resorption respond to N and P addition in alpine grasslands is poorly understood.Therefore,we conducted an N and P addition experiment(involving control,N addition,P addition,and N+P addition)in an alpine grassland on Kunlun Mountains(Xinjiang Uygur Autonomous Region,China)in 2016 and 2017 to investigate the changes in leaf nutrient concentrations(i.e.,leaf N,Leaf P,and leaf N:P ratio)and nutrient resorption efficiency of Seriphidium rhodanthum and Stipa capillata,which are dominant species in this grassland.Results showed that N addition has significant effects on soil inorganic N(NO_(3)^(-)-N and NH_(4)^(+)-N)and leaf N of both species in the study periods.Compared with green leaves,leaf nutrient concentrations and nutrient resorption efficiency in senesced leaves of S.rhodanthum was more sensitive to N addition,whereas N addition influenced leaf N and leaf N:P ratio in green and senesced leaves of S.capillata.N addition did not influence N resorption efficiency of the two species.P addition and N+P addition significantly improved leaf P and had a negative effect on P resorption efficiency of the two species in the study period.These influences on plants can be explained by increasing P availability.The present results illustrated that the two species are more sensitive to P addition than N addition,which implies that P is the major limiting factor in the studied alpine grassland ecosystem.In addition,an interactive effect of N+P addition was only discernable with respect to soil availability,but did not affect plants.Therefore,exploring how nutrient characteristics and resorption response to N and P addition in the alpine grassland is important to understand nutrient use strategy of plants in terrestrial ecosystems. 展开更多
关键词 leaf nutrient concentration nutrient resorption efficiency leaf N:P ratio N addition P addition Seriphidium rhodanthum Stipa capillata
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Effect of exclosure ages on woody plant structure,diversity and regeneration potential in the western Tigray region of Ethiopia 被引量:1
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作者 Tsegay Gebregerges Zewdu K.Tessema Emiru Birhane 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第3期693-703,共11页
Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, incr... Exclosure is a method of rehabilitating degraded lands by protecting them from the interference of animals and from human encroachment, and is used to regenerate native vegetation as a way to reduce soil erosion, increase rain water infiltration and provide fodder and woody biomass in degraded grazing lands. Therefore, we studied woody plant structure, diversity and regeneration potentials in 5-and 10-year grazing exclosures in comparison with open grazed sites in a semi-arid environment. Data on species diversity, abundance, structure, basal area, frequency, density, and regeneration status were collected from 270 sample plots. Forty-one woody species representing 20 families were identified, with 18, 28 and 38 species found in open grazed areas, and in 5-and 10-year grazing exclosures, respectively. The 10-year grazing exclosures had a higher(P <0.05) species richness and plant densities compared to the 5-year grazing exclosures and the open grazed areas. The population structure and regeneration status of woody species in both grazing exclosures showed an inverted J-shape, indicating a healthy regeneration status, whereas hampered regeneration was observed in open grazed areas. The establishment of grazing exclosures had positive effects in restoring woody plant diversity and improving vegetation structure and regeneration potentials of degraded grazing lands. 展开更多
关键词 Basal area DIVERSITY Important value index Population structure Regeneration status Species composition EXCLOSURES
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Effect of Soil and Water Conservation Measures on Selected Soil Physical and Chemical Properties and Barley (Hordeum spp.) Yield 被引量:1
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作者 Tadele Amdemariam Yihenew G. Selassie +1 位作者 Mitiku Haile C. Yamoh 《Journal of Environmental Science and Engineering》 2011年第11期1483-1495,共13页
A study was conducted in 2007/2008 at Absela locality, Banja Shikudad District of the Amhara National Regional State, Ethiopia to evaluate the effects of soil bunds stabilized with vetiver grass (IT. zizanioides) an... A study was conducted in 2007/2008 at Absela locality, Banja Shikudad District of the Amhara National Regional State, Ethiopia to evaluate the effects of soil bunds stabilized with vetiver grass (IT. zizanioides) and tree lucerne (C. palmensis) on soil physical and chemical properties, bund height, inter-terrace slope and barley (Hordeum vulgare L.) yield. Data were analyzed using one-way analysis of variance (ANOVA) and mean values for the treatments were separated using Duncan's Multiple Range Test. Results indicated that the non-conserved fields had significantly (p 〈 0.05) lower organic carbon and was found to contain 66% less OM from the average of the conserved treatment. 9-year old sole soil bund, the 9-year old soil bund stabilized with tree lucerne, the 9-year old soil bund stabilized with vetiver, and the 6-year old soil bund stabilized with tree lucerne had 71.20, 68.56, 52.30, and 36.12%, respectively higher percent OM than the control treatment. The trend was similar for total nitrogen. The non-conserved treatment had a higher bulk density when compared to the conserved fields. Fields with soil bunds stabilized with vetiver grass had the highest bund height and the lowest inter-terrace slope than fields treated with the rest of remaining conservation measures. Barley grain yields were significantly (P 〈 0.05) greater in both the soil accumulation and loss zones of the conserved fields than the non-conserved (control) treatment. Practicing soil conservation measures and curtailing causes of land degradation could improve the soil physical and chemical properties thereby increase land productivity of the conserved land. 展开更多
关键词 Organic carbon soil bund total N tree lucerne vetiver
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Healing Effect and Underlying Mechanism of Silver Nanoparticles Prepared Using Carboxymethyl Chitosan under Solar Irradiation
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作者 Yi Long Chunling Zhang +7 位作者 Lan Chen Tietao Di Lu Chen Lisha Tang Kaizhong Luo Yu Yan Pingzhen Tong Jie Xiang 《Journal of Renewable Materials》 SCIE EI 2021年第6期1075-1085,共11页
In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanopartic... In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanoparticles prepared by this method were evaluated for healing wounds in rats with diabetes.We also attempted to determine the underlying mechanism and influencing factors of the silver nanomaterial preparation method.Compared with growth factors,silver nanoparticles exhibit better healing effects for rats with diabetes.No remnant silver ions were detected in the major organs of these rats after the application of silver nanoparticles.Silver nanoparticles prepared using CMCS are less toxic than those prepared from the conventional method,promote the proliferation of skin fibroblasts,and are promising as a topical medication for infected wounds.An obvious breakage process of the particles is observed during the growth of nanocrystalline silver in CMCS.In this study,we also attempted to determine whether this method is suitable for synthesizing silver nanoparticles using N-trimethyl chitosan chloride and sodium alginate were used in this particular experiment.The characteristic UV-vis absorbance peak of silver nanoparticles was found only in the reaction mixture containing N-trimethyl chitosan chloride.Our study demonstrates that free radicals are the key factor in this silver nanoparticle preparation method. 展开更多
关键词 Silver nanoparticle carboxymethyl chitosan low toxicity HEALING free radical
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Phthalate Esters Biodegradation by Fusarium oxysporum in Vegetable Soil
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作者 LV Hui-ying LI Gao-yang +3 位作者 FANG Zhi-hui ZHANG Fan LIANG Zeng-enni SHAN Yang 《Agricultural Science & Technology》 CAS 2019年第1期37-41,54,共6页
In this research, soil samples were first polluted with 6 PAEs (i.e. DMP, DEP, DIBP, DBP, DEHP, and BBP) at 3 different concentration gradients (0, 10, and 20 mg/kg) and then treated with a highly-efficient degradatio... In this research, soil samples were first polluted with 6 PAEs (i.e. DMP, DEP, DIBP, DBP, DEHP, and BBP) at 3 different concentration gradients (0, 10, and 20 mg/kg) and then treated with a highly-efficient degradation fungus, Fusarium oxysporum (PO-Yi), to investigate the biodegradation of PAEs in pepper and eggplant soil. The findings revealed that PO-Yi can accelerate the degradation of PAEs in vegetable soils including pepper and eggplant soil to varying degrees. The highest absolute degradation rate (up to 39.5%) was observed in DEP-treated soils at the high pollution level (20 mg/kg), which was 14.2% higher than that at the middle pollution level (10 mg/kg). The degradation effect in the pepper soil was superior to that in the eggplant soil. Vegetable soil, either pepper soil or eggplant soil, which was polluted by various PAEs at different pollution gradients and then treated with PO-Yi fungus presented good bioremediation results. In the pepper and eggplant soil, 76.8% and 63.1% of the PAEs with a total volume of 60 mg/kg were degraded within 30 d respectively. PO-Yi, indigenous microorganisms, and the vegetables, i.e. pepper and eggplant had good synergistic effects on the degradation of compound PAEs in PAEpolluted pot soil. 展开更多
关键词 Fusarium oxysporum (PO-Yi) PHTHALATES SOIL BIODEGRADATION Pot experiment
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