[Objective] The aim was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by different land use types.[Method]Soil organic carbon,active soil organic carbo...[Objective] The aim was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by different land use types.[Method]Soil organic carbon,active soil organic carbon and soil carbon management index（CMI）of different land use types in Guilin Maocun karst area were studied.Sampling with field investigation and laboratory testing was carried out.Heavy potassium chromate method was adopted to determine soil organic matter.333 mmol/L KMnO4 oxidation method was used to determine active organic carbon.[Result]With active soil organic matter increasing,the differences of CMI between different land use types were bigger.The CMI value of different land uses was shrubforest paddy fielddry farmland.The statistical analysis showed that labile organic matter was related with major soil properties at a significant level.[Conclusion]Labile organic matter could be used to reveal the influence of different land use types on soil organic matter and carbon management index in karst area.展开更多
This work presents the potentiostatic anodization study of titania nanotube array films fabricated in fluoride-based organic electrolytes including DEG （diethylene glycol） and EG （ethylene glycol）. The work focuse...This work presents the potentiostatic anodization study of titania nanotube array films fabricated in fluoride-based organic electrolytes including DEG （diethylene glycol） and EG （ethylene glycol）. The work focuses on the effect of important anodization parameters such as applied voltage, anodization time, and electrolyte type on nanotube morphologies and corresponding surface properties. Depending upon unique nanotube formation structures obtained from each anodizing electrolyte, wettability of the nanotube array layer has been determined by means of the contact angle measurement. The EG nanotube array films with close-packing cell orientation are found to show hydrophilic behavior. While the well separated DEG nanotube array films are found to exhibit hydrophobic behavior, with the characteristics of more discrete, wider cell separation obtained through manipulating the electrolyte conditions and the fabrication techniques offering considerable prospects for developing the superhydrophobic sample surface. Such formation structures observed for the DEG fabricated nanotube is believed to play a prominent role in determining the surface wettability of the anodized nanotube array film. The achieved result in this work is anticipated to pave the way to other relevant applications, where interfacial properties are critically concerned.展开更多
To get a better understanding of the spatial impact of organic discharges on stream water quality,a "scenario-testing" approach was proposed to examine how a change in plant treatment efficiency would affect...To get a better understanding of the spatial impact of organic discharges on stream water quality,a "scenario-testing" approach was proposed to examine how a change in plant treatment efficiency would affect dissolved oxygen(DO) concentration along a stream.An "upper-lower" boundary technique was applied to conduct sensitivity analysis to observe the responses of DO concentration to different DO-related parameters.The results show a non-linear discrepancy of biochemical oxygen demand(BOD) and DO concentration among different treatment scenarios,which indicates the higher the efficiency of the plant treatment,the shorter the time the stream needs to recover.The sensitivity analysis reveals that the larger the amount of the waste discharge,the more sensitive the BOD to the biological removal parameter.In addition,the DO is more sensitive to the biological removal parameter than to the reaeration parameter.展开更多
Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicat...Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology （earthworms） and physical quality （aggregate stability, macroporosity and infiltration rate）. There were i 5 treatment combinations tested. The first factor is the type of organic matter： （1） cattle manure （CM）, （2） filter cake （FC）, （3） sugarcane trash （ST）, （4） a mixture ofCM ＋ FC and （5） a mixture of CM ＋ ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment （without organic matter input）. The result of this research showed that the highest population density of earthworms was found in the treatment of ST （78 individuals/m2） and a mixture of CM ＋ ST （84 individuals/m2）. The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity （from r = 0.683 to r = 0.606） and infiltration rate （from r = 0.669 to r = 0.756）. The results of this study suggest a mixture of CM ＋ ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.展开更多
The study area is located in Duhok province-Kurdistan region-Northern Iraq and including two locations the first location is situated in Galbook village and the vegetation cover is trees of （Quercus aegilops L.）, th...The study area is located in Duhok province-Kurdistan region-Northern Iraq and including two locations the first location is situated in Galbook village and the vegetation cover is trees of （Quercus aegilops L.）, the second location is situated in Koradeer village that covered with threes of Prunus dulcis （Mill.） Webb.. Disturbed surface soil samples at depth 0-30 cm were collected at four different distances （1, 5, 10 and 15 m） from the tree with randomized selection three trees in each study location. Soil organic matter decreases with increasing distances from tree in both locations under two different trees species, which is attributed to the effect of tree crown. Ordinarily, organic matter content in both locations correspond to the requirements of Mollisols. Statistical analysis of data showed significant differences in organic matter content between locations. Cation exchange capacity is high under tree crown and decreasing with distances from tree in both locations, as a result of decreasing organic matter and increasing calcium carbonate with distances. Commonly soil pH is slightly increased with increasing distances from tree because of increasing calcium carbonate with distances and decreasing organic matter content. Calcium was not uniform with distances and Mg decreasing with distances in both locations. The values of fine clay/coarse clay and fine clay/total clay of soil samples confirm development of the soils under study. Porosity percentage under tree crown is high and decreasing with distances. Soil bulk density was increased with distances in both locations, as a result of decreasing organic matter content with distances. This study aims to explain the effect of tree distances and species on the mollic horizon properties.展开更多
The effect of cement on physiochemical properties of three types of soils i.e garden soil, agricultural soil and roadside soil was investigated. The ordinary Portland cement was used. The amount of cement added to soi...The effect of cement on physiochemical properties of three types of soils i.e garden soil, agricultural soil and roadside soil was investigated. The ordinary Portland cement was used. The amount of cement added to soil samples, as dry mass percentage was 20%. The results of analysis showed that the addition of cement is capable of bringing about changes in physiochemical properties of soil. The electrical conductivity and organic matter content in three soils get decreased by the addition of cement. While the pH, bulk density and water holding capacity of soils after the addition of cement gets increased. The soil found most suitable to be treated with cement was roadside soil. It was concluded that cement can be used to change the physiochemical properties of soil and this technique has great utility in improving the quality of problematic soils.展开更多
Metam sodium （MS; sodium N-methyl dithiocarbamate） has emerged as a promising soil fumigant in the US to replace methyl bromide （MeBr）. Metam potassium （MK; potassium N-methyl dithiocarbamate） and MS break down ...Metam sodium （MS; sodium N-methyl dithiocarbamate） has emerged as a promising soil fumigant in the US to replace methyl bromide （MeBr）. Metam potassium （MK; potassium N-methyl dithiocarbamate） and MS break down into the volatile gas methyl isothiocyanate （MITC） to control soil borne pests. Many studies have focused on MS, but MK has not been studied as thoroughly. The objective of this research was to determine the effect of increasing organic matter （OM） treatments and soil texture to minimize the off-gassing of MS and MK. Bench-scale soil column studies were performed to simulate organic matter treatments that may decrease the volatilization loss of MITC. Incorporation depth of OM simulated surface tillage （0-15 cm） practices. Soil was packed in steel columns and MS or MK was applied at a depth of 15 cm and MITC volatilization was measured using gas chromatography/mass spectroscopy. Volatilization of MITC behaved similarly for MS and MK with MITC movement impacted by soil texture. MITC volatilization was lower from a sandy clay loam than a sandy soil. Surface incorporation of OM did not significantly decrease MITC volatilization. These results suggest that soil texture is the dominant factor reducing MITC off-gassing and prolonging the time needed to control soil borne pests.展开更多
Carbon of humus acids(HSAC) and dissolved organic carbon(DOC) are the most active forms of soil organic carbon(SOC) and play an important role in global carbon recycling. We investigated the concentrations of HSAC,wat...Carbon of humus acids(HSAC) and dissolved organic carbon(DOC) are the most active forms of soil organic carbon(SOC) and play an important role in global carbon recycling. We investigated the concentrations of HSAC,water-soluble organic carbon(WSOC),hot water-extractable organic carbon(HWOC) and SOC in soils under different vegetation types of four copper mine tailings sites with differing vegetation succession time periods in Tongling,China. The concentrations of HSAC,WSOC,HWOC and SOC increased with vegetation succession. WSOC concentration increased with the accumulation of SOC in the tailings,and a linearly positive correlation existed between the concentrations of HSAC and SOC in the tailings. However,the percentages of HSAC and DOC in the SOC decreased during vegetation succession. The rate of SOC accumulation was higher when the succession time was longer than 20 years,whereas the speeds of soil organic matter(SOM) decomposition and humification were slow,and the concentrations of HSAC and DOC increased slowly in the tailings. The percentage of carbon of humic acid(HAC) in HSAC increased with vegetation succession,and the values of humification index(HI),HAC/carbon of fulvic acid,also increased with the accumulation of HSAC and SOC in soils of the tailings sites. However,the HI value in the each of the tailings was less than 0.50. The humification rate of SOM was lower than the accumulation rate of SOM,and the level of soil fertility was still very low in the tailings even after 40 years of natural restoration.展开更多
基金Supported by the Work Project of China Geological Survey(1212010911062)Open Foundation of Karst Dynamics Laboratory(kdl2008-10)+1 种基金Guangxi Zhuang Autonomous Region Innovation Project(0842008)National Natural Science Foundation(40872213)~~
文摘[Objective] The aim was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by different land use types.[Method]Soil organic carbon,active soil organic carbon and soil carbon management index（CMI）of different land use types in Guilin Maocun karst area were studied.Sampling with field investigation and laboratory testing was carried out.Heavy potassium chromate method was adopted to determine soil organic matter.333 mmol/L KMnO4 oxidation method was used to determine active organic carbon.[Result]With active soil organic matter increasing,the differences of CMI between different land use types were bigger.The CMI value of different land uses was shrubforest paddy fielddry farmland.The statistical analysis showed that labile organic matter was related with major soil properties at a significant level.[Conclusion]Labile organic matter could be used to reveal the influence of different land use types on soil organic matter and carbon management index in karst area.
文摘This work presents the potentiostatic anodization study of titania nanotube array films fabricated in fluoride-based organic electrolytes including DEG （diethylene glycol） and EG （ethylene glycol）. The work focuses on the effect of important anodization parameters such as applied voltage, anodization time, and electrolyte type on nanotube morphologies and corresponding surface properties. Depending upon unique nanotube formation structures obtained from each anodizing electrolyte, wettability of the nanotube array layer has been determined by means of the contact angle measurement. The EG nanotube array films with close-packing cell orientation are found to show hydrophilic behavior. While the well separated DEG nanotube array films are found to exhibit hydrophobic behavior, with the characteristics of more discrete, wider cell separation obtained through manipulating the electrolyte conditions and the fabrication techniques offering considerable prospects for developing the superhydrophobic sample surface. Such formation structures observed for the DEG fabricated nanotube is believed to play a prominent role in determining the surface wettability of the anodized nanotube array film. The achieved result in this work is anticipated to pave the way to other relevant applications, where interfacial properties are critically concerned.
基金Projects PGSD3-334033-2006 supported by the Natural Sciences and Engineering Research Council of Canada2007-2008 by the Canadian Forest Service of Natural Resources
文摘To get a better understanding of the spatial impact of organic discharges on stream water quality,a "scenario-testing" approach was proposed to examine how a change in plant treatment efficiency would affect dissolved oxygen(DO) concentration along a stream.An "upper-lower" boundary technique was applied to conduct sensitivity analysis to observe the responses of DO concentration to different DO-related parameters.The results show a non-linear discrepancy of biochemical oxygen demand(BOD) and DO concentration among different treatment scenarios,which indicates the higher the efficiency of the plant treatment,the shorter the time the stream needs to recover.The sensitivity analysis reveals that the larger the amount of the waste discharge,the more sensitive the BOD to the biological removal parameter.In addition,the DO is more sensitive to the biological removal parameter than to the reaeration parameter.
文摘Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology （earthworms） and physical quality （aggregate stability, macroporosity and infiltration rate）. There were i 5 treatment combinations tested. The first factor is the type of organic matter： （1） cattle manure （CM）, （2） filter cake （FC）, （3） sugarcane trash （ST）, （4） a mixture ofCM ＋ FC and （5） a mixture of CM ＋ ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment （without organic matter input）. The result of this research showed that the highest population density of earthworms was found in the treatment of ST （78 individuals/m2） and a mixture of CM ＋ ST （84 individuals/m2）. The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity （from r = 0.683 to r = 0.606） and infiltration rate （from r = 0.669 to r = 0.756）. The results of this study suggest a mixture of CM ＋ ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.
文摘The study area is located in Duhok province-Kurdistan region-Northern Iraq and including two locations the first location is situated in Galbook village and the vegetation cover is trees of （Quercus aegilops L.）, the second location is situated in Koradeer village that covered with threes of Prunus dulcis （Mill.） Webb.. Disturbed surface soil samples at depth 0-30 cm were collected at four different distances （1, 5, 10 and 15 m） from the tree with randomized selection three trees in each study location. Soil organic matter decreases with increasing distances from tree in both locations under two different trees species, which is attributed to the effect of tree crown. Ordinarily, organic matter content in both locations correspond to the requirements of Mollisols. Statistical analysis of data showed significant differences in organic matter content between locations. Cation exchange capacity is high under tree crown and decreasing with distances from tree in both locations, as a result of decreasing organic matter and increasing calcium carbonate with distances. Commonly soil pH is slightly increased with increasing distances from tree because of increasing calcium carbonate with distances and decreasing organic matter content. Calcium was not uniform with distances and Mg decreasing with distances in both locations. The values of fine clay/coarse clay and fine clay/total clay of soil samples confirm development of the soils under study. Porosity percentage under tree crown is high and decreasing with distances. Soil bulk density was increased with distances in both locations, as a result of decreasing organic matter content with distances. This study aims to explain the effect of tree distances and species on the mollic horizon properties.
文摘The effect of cement on physiochemical properties of three types of soils i.e garden soil, agricultural soil and roadside soil was investigated. The ordinary Portland cement was used. The amount of cement added to soil samples, as dry mass percentage was 20%. The results of analysis showed that the addition of cement is capable of bringing about changes in physiochemical properties of soil. The electrical conductivity and organic matter content in three soils get decreased by the addition of cement. While the pH, bulk density and water holding capacity of soils after the addition of cement gets increased. The soil found most suitable to be treated with cement was roadside soil. It was concluded that cement can be used to change the physiochemical properties of soil and this technique has great utility in improving the quality of problematic soils.
文摘Metam sodium （MS; sodium N-methyl dithiocarbamate） has emerged as a promising soil fumigant in the US to replace methyl bromide （MeBr）. Metam potassium （MK; potassium N-methyl dithiocarbamate） and MS break down into the volatile gas methyl isothiocyanate （MITC） to control soil borne pests. Many studies have focused on MS, but MK has not been studied as thoroughly. The objective of this research was to determine the effect of increasing organic matter （OM） treatments and soil texture to minimize the off-gassing of MS and MK. Bench-scale soil column studies were performed to simulate organic matter treatments that may decrease the volatilization loss of MITC. Incorporation depth of OM simulated surface tillage （0-15 cm） practices. Soil was packed in steel columns and MS or MK was applied at a depth of 15 cm and MITC volatilization was measured using gas chromatography/mass spectroscopy. Volatilization of MITC behaved similarly for MS and MK with MITC movement impacted by soil texture. MITC volatilization was lower from a sandy clay loam than a sandy soil. Surface incorporation of OM did not significantly decrease MITC volatilization. These results suggest that soil texture is the dominant factor reducing MITC off-gassing and prolonging the time needed to control soil borne pests.
基金Supported by the National High Technology Research and Development Program(863 Program)of China(No.2006AA06Z359)the National Environmental Protection Public Welfare Science and Technology Research Program of China(No.201009041)the Special Foundation for Young Scientists of Anhui Province,China(No.2010SQRL150)
文摘Carbon of humus acids(HSAC) and dissolved organic carbon(DOC) are the most active forms of soil organic carbon(SOC) and play an important role in global carbon recycling. We investigated the concentrations of HSAC,water-soluble organic carbon(WSOC),hot water-extractable organic carbon(HWOC) and SOC in soils under different vegetation types of four copper mine tailings sites with differing vegetation succession time periods in Tongling,China. The concentrations of HSAC,WSOC,HWOC and SOC increased with vegetation succession. WSOC concentration increased with the accumulation of SOC in the tailings,and a linearly positive correlation existed between the concentrations of HSAC and SOC in the tailings. However,the percentages of HSAC and DOC in the SOC decreased during vegetation succession. The rate of SOC accumulation was higher when the succession time was longer than 20 years,whereas the speeds of soil organic matter(SOM) decomposition and humification were slow,and the concentrations of HSAC and DOC increased slowly in the tailings. The percentage of carbon of humic acid(HAC) in HSAC increased with vegetation succession,and the values of humification index(HI),HAC/carbon of fulvic acid,also increased with the accumulation of HSAC and SOC in soils of the tailings sites. However,the HI value in the each of the tailings was less than 0.50. The humification rate of SOM was lower than the accumulation rate of SOM,and the level of soil fertility was still very low in the tailings even after 40 years of natural restoration.
