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The effect of total carbon on microscopic soil properties and implications for crop production

Journal of Arid Land 2012年第3期4卷 251-259页

作者： Inma LEBRON Milton Earl MCGIFFEN Jr Donald Louis SUAREZ Centre for Ecology and Hydrology Bangor Gwynedd LL57 2UW UK Department of Botany and Plant Science University of California Riverside CA 92521-0334 USA U.S. Salinity Laboratory Riverside CA 92521-0334 USA

Soil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in microbial activity and soil water retention are often suggested as reasons for the rise in crop yield when organic matter is added to the soil. Less is known about the direct effect of changes in soil structure on crop production. A field experiment was conducted to study the effect of summer cover crop and in-season management system on soil structure. The experiment was a nested design with summer cover crop as the main plot and management system as the subplot. Summer cover crop treatments included cowpea （Vigna unguiculata L. Walp.） incorporated into the soil in the fall （CI）, cowpea used as mulch in the fall （CM）, sudangrass （Sorghum vulgare） incorporated into the soil in the fall （S）, and dry fallow or bare ground （B）. Management systems were organic （ORG） and conventional （CNV） systems. Lettuce （Lactuca sativa L.） and cantaloupes （Cucumis melo L.） were cultivated in rotation in the plots for three consecutive years using the same cover crops and management systems for each plot. Disturbed and undisturbed soil cores were collected at the end of the third year and used for laboratory experiments to measure physical, chemical, and hy- draulic properties. Image analysis was used to quantify soil structure properties using a scanning electron micro- scope on thin sections prepared from the undisturbed soil cores. We found that total soil carbon was correlated with porosity, saturation percentage, and pore roughness. Pore roughness was correlated with crop production in gen- eral and with marketable production in particular. We found that the higher the complexity of the pore space, the more water retained in the soil, which may increase soil water residence and reduce plant

关键词： summer cover crop management systems soil structure properties total carbon

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Impact of mangrove vegetation on seasonal carbon burial and other sediment characteristics in the Vellar-Coleroon estuary, India

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Journal of Forestry Research 2014年第4期25卷 787-794页

作者： Kandasamy Kathiresan Venugopal Gomathi Raj Anburaj Kandasamy Saravanakumar Centre of Advanced Study in Marine Biology Faculty of Marine Sciences Annamalai University Parangipettai 608 502 India

This work quantified the total carbon and 12 other sediment characteristics at 10 soil depths, in planted and or natural mangrove forests in comparison with non-vegetated soil for four seasons of the year 2009-2010 in the Vellar-Coleroon estuarine complex, India. The sedi- ment characteristics varied significantly between mangrove-vegetated and non-vegetated habitats or seasons of analysis, but not between soil depths. The mangrove sediments were rich in total carbon and total or- ganic carbon as compared to non-mangrove sediments （p 〈0.01）. total carbon was 98.2% higher in mature mangroves and 41.8% in planted mangroves than that in non-mangrove soil. total organic carbon was as much as 2.5 times greater in mature mangroves and 2 times greater in planted mangroves than that in unvegetated soil. carbon contents also varied many fold by season. total carbon content was 8.6 times greater during pre-monsoon, 4.1 times greater during post-monsoon and 2.5 times greater during monsoon than during summer （P〈0.01 in all cases）. Similarly, total organic carbon was 5.9 times greater during pre-monsoon, 3.1 times greater during post-monsoon and 69% greater during monsoon than during summer. In general, higher levels of sediment carbon were recorded during pre and post-monsoon seasons than during other seasons. total carbon concentration was correlated negatively to temperature, sand and phosphorus （P 〈0.01）; positively correlated with redox potential, silt, clay, C/N ratio, potassium （P 〈0.01） and nitrogen （P〈0.05）; but not correlated with soil depth, pH or salinity. This work revealed that the carbon burial was rapid at the annual rate of 2.8% for total carbon, and 6.7% for total organic carbon in mangrove-planted sediment. Cleating of mangroves can result in significantly and rapidly reduced carbon *** study highlights the importance of natural and plantation mangrove stands for conserving sediment carbon in the tropical coastal domain.

关键词： mangrove sediment carbon burial total carbon total organiccarbon

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Diesel engine exhaust exposures in two underground mines

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International Journal of Mining Science and Technology 2017年第4期27卷 641-645页

作者： Debia Maximilien Couture Caroline Njanga Pierre-Eric Neesham-Grenon Eve Lachapelle Guillaume Coulombe Hugo Hallé Stéphane Aubin Simon Department of Environmental and Occupational Health School of Public Health Universite de Montreal 2375 chemin de la Cote Ste-Catherine Montreal H3T IA8 Canada Department of Mechanical Engineering F.cole de Technologie Superieure 1100 rue Notre-Dame Ouest Montreal H3C 1K3 Canada Health and Safety Agnico Eagie Mines 145 King Street East Suite 400 Toronto MSC 2Y7 Canada Health and Safety Westwood Mine (IAMGOLD) Chemin Arthur Doyon PreissacJOY 2EO Canada Institut de recherche Robert-Sauve en sante et en securite du travail (IRSST) 505 Boul. de Maisonneuve Ouest Montreal H3A 3C2 Canada

Exposure to diesel engine exhaust(DE) is a major concern in underground mines. It has been linked to cardiopulmonary diseases and is classified as a human carcinogen. The goal of this study is to assess DE exposures in workers at two underground gold mines, to compare exposure levels within and between the mines, and to compare different methods of measuring DE exposures, namely respirable combustible dust(RCD), elemental carbon(EC) and total carbon(TC). Ambient and personal breathing zone(PBZ) measurements were taken. Side-by-side monitoring of RCD and of the respirable fraction of EC and TC(EC_Rand TC_R) was carried out in the workers' breathing zone during full-shift *** ambient measurements, in addition to EC_R, TC_Rand RCD, a submicron aerosol fraction(less than 1 mm) of EC and TC was also sampled(EC_1and TC_1). Average ambient results of 240 mg/m^3 in RCD, 150 mg/m^3 in EC_Rand 210 mg/m^3 in TC_Rare obtained. Average PBZ results of 190 mg/m^3 in RCD,84 mg/m^3 in EC3Rand 150 mg/min TC_Rare obtained. Very good correlation is found between EC_Rand EC_1 with a Pearson correlation coefficient of 0.99(p carbon can skew the interpretation of results when relying only on TC data.

关键词： Diesel exposure Underground mine Respirable combustible dust Elemental carbon total carbon Diesel particulate matter Similar exposure groups

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Enzyme Activity in Water-Stable Soil Aggregates as Affected by Long-Term Application of Organic Manure and Chemical Fertiliser

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Pedosphere 2013年第1期23卷 111-119页

作者： LIU Yi-Ren LI Xiang SHEN Qi-Rong XU Yang-Chun Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization College of Resources and Environmental SciencesNanjing Agricultural University Institute of Soil Fertilizer and Resource Environment Jiangxi Academy of Agricultural Sciences

The activities of invertase, protease, urease, acid phosphomonoesterase, dehydrogenase, and catalase in different fractions of waterstable aggregates (WSA) were examined in long-term (26 years) fertilised soils. The long-term application of organic manure (OM) with chemical fertiliser (CF) significantly increased macroaggregate and decreased microaggregate percentages, enhanced the mean weight diameter, and significantly increased soil total carbon (TC) and total nitrogen (TN) contents of WSA in different size fractions. Combined fertilisation with OM and CF also increased invertase, protease, urease, acid phosphomonoesterase, dehydrogenase, and catalase activities of WSA in different size fractions. Enzyme activities were higher in macroaggregates than in microaggregates. The distribution of enzyme activities generally followed the distribution of TC and TN in WSA. The geometric mean of the enzyme activities in different WSA of OM-treated soils was significantly higher than that in soils treated with 100% CF or no fertiliser. The results indicated that the long-term combined application of OM with CF increased the aggregate stability and enzyme activity of different WSA sizes, and consequently, improved soil physical structure and increased soil microbial activity.

关键词： distribution mean weight diameter stability total carbon total nitrogen

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Temporal Variability in Fine carbonaceous Aerosol over Two Years in Two Megacities:Beijing and Toronto

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Advances in Atmospheric Sciences 2010年第3期27卷 705-714页

作者：杨复沫 Jeffrey BROOK 贺克斌段凤魁马永亮 College of Earth Science Graduate University of the Chinese Academy of Sciences Atmospheric Science and Technology Directorate/Science and Technology Branch Department of Environmental Science and Engineering Tsinghua University

Time-series of weekly total carbon （TC） concentrations of fine aerosol particles （PM2.5） in Beijing and Toronto were compared to investigate their respective levels and temporal patterns over two years from August 2001 through July 2003. In addition to this comparison, differences in the factors contributing to the observed concentrations and their temporal variations are discussed. Based upon past knowledge about the two megacities with highly contrasting air pollutant levels, it is not surprising that the average TC concentration in Belling （31.5 μg C m^-3） was greater than that in Toronto by a factor of 8.3. Despite their large concentration differences, in both cities TC comprised a similarly large component of PM2.5. TC concentrations exhibited very different seasonal patterns between the two cities. In Beijing, TC experienced higher levels and greater weekly fluctuations in winter whereas in Toronto this behavior was seen in summer. As a result, the greatest gap in TC concentrations between Beijing and Toronto （by a factor of 12.7） occurred in winter, while the smallest gap （a factor of 4.6） was in summer. In Beijing, seasonal variations in the emissions probably played a greater role than meteorology in influencing the TC seasonality, while in Toronto during the warm months more than 80% of the hourly winds were recorded from the south, along with many potential anthropogenic sources for the days with high TC concentrations. This comparison of the differences provides insight into the major factors affecting carbonaceous aerosol in each city.

关键词： total carbon PM2.5 temporal variation carbonaceous aerosol Beijing Toronto

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Real-time Diesel Particulate Matter ambient monitoring in underground mines

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Journal of Coal Science & Engineering(China) 2011年第3期17卷 225-231页

作者： Gillies A D S Missouri University of Science and Technology Rolla Missouri USA

A real-time Diesel Particulate Matter （DPM） monitor has been developed on the base of the successful National In- stitute of Occupational Health and Safety （NIOSH） designed Personal Dust Monitor （PDM） unit. The objectives of a recently completed Australian Coal Association Research Program （ACARP） study was to modify the PDM to measure the submicrometre fraction of the aerosol in a real-time monitoring underground instrument. Mine testing focused on use of the monitor in engineering evaluations of Longwall （LW） moves demonstrated how DPM concentrations from vehicles fluctuate under varying ventilation and operational conditions. The strong influence of mine ventilation systems is reviewed. Correlation between the current SKC DPM measurement system and real-time DPM monitors were conducted and results from eight mines show a correlation between elemental carbon （EC） and the new monitor DPM mass ranging from 0.45 to 0.82 with R2〉0.86 in all but two cases. This differences in suspected to be due to variations from mine to mine in aspects such as mine atmospheric contamination, vehicle fleet variations, fuel type, engine maintenance, engine combustion efficiency, engine behavior or interference from other submicrometre aerosol. Real-time monitoring clearly reflects the movement of individual diesel vehicles and allows pin-pointing of high exposure zones such as those encountered where various vehicles engage in intense work in areas of constrained or difficult ventilation. DPM shift average monitoring approaches do not readily allow successful engineering evaluation exercises to determine acceptability of pollution levels. Identification of high DPM concentration zones allows efficient modification of mine ventilation, operator positioning and other work practices to reduce miners＇ exposures without waiting for laboratory analysis results.

关键词： real-time diesel particulate matter total carbon elemental carbon

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carbon Mineralization Associated with Soil Aggregates as Affected by Short-term Tillage

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Journal of Resources and Ecology 2016年第2期7卷 101-106页

作者：郭琳琳西村拓井本博美孙志刚中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室北京100101 日本东京大学农学与生命科学研究科

Abstract： Tillage practice has received much attention due to its effects on greenhouse gas emissions from agricultural fields. The understanding of carbon mineralization associated with soil aggregates helps to explore the influence mechanisms of tillage practice on soil carbon dynamics. total carbon and carbon mineralization rates associated with various sizes of soil aggregates under no-tillage and tillage treatments were studied with a volcanic ash soil. total carbon content in microaggregates （〈0.25 mm） was higher than that in macroaggregates （〉0.25 mm） for both the no-tillage and tillage treatments, since microaggregates of the volcanic ash soil include more fine silts and clay particles absorbing more organic agents. The carbon mineralization rate and total carbon were highly correlated （R2 = 0.6552, P= 0.002） for both treatments, suggesting that soil aggregate size is an important factor to influence the carbon mineralization rate. The no-tillage system showed the advantage of improving soil structure for volcanic ash soil. A larger proportion of microaggregates with relatively high carbon mineralization might contribute to the greater carbon loss from tilled soils. Unlike aggregate size, short-term tillage showed no significant effects on carbon mineralization rates associated with aggregates in a specific size class.

关键词： carbon mineralization rate soil aggregates tillage total carbon

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应用红外碳硫仪测定碳化硅中总碳、游离碳及碳化硅

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冶金分析 2004年第Z1期24卷 363-页

作者：梁文天津铁厂质监处中化室天津300450

　　碳化硅是一种常用的脱氧剂,在炼钢过程中主要用于脱氧以提高钢水的内在质量.碳化硅日常分析项目主要有碳化硅、游离碳及总碳,一般采用GB/T3045-89中规定的分析方法,分析过程繁琐、分析时间长,应用于生产过程中批量检验不能很好的满... 详细信息

　　碳化硅是一种常用的脱氧剂,在炼钢过程中主要用于脱氧以提高钢水的内在质量.碳化硅日常分析项目主要有碳化硅、游离碳及总碳,一般采用GB/T3045-89中规定的分析方法,分析过程繁琐、分析时间长,应用于生产过程中批量检验不能很好的满足要求.本文对碳化硅的分析方法进行了试验和探讨,应用红外碳硫分析仪测定碳化硅中的总碳量和碳化硅量进而计算出游离碳的量,其重现性和再现性均较好.……

关键词：应用红外碳硫仪分析仪测定碳化硅总碳量游离碳 total carbon 分析方法脱氧剂生产过程批量检验内在质量炼钢过程分析时间再现性重现试验计算硅量钢水

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