This article, by combining field investigation with laboratorial analysis, studies diverse alpine meadow at the Eastern Margin of the Qinghai-Tibet Plateau for the underground biomass dynamics, vertical distribution o...This article, by combining field investigation with laboratorial analysis, studies diverse alpine meadow at the Eastern Margin of the Qinghai-Tibet Plateau for the underground biomass dynamics, vertical distribution of the content of soil carbon and nitrogen, the connection between the biomass and the content of carbon and nitrogen. The studies show that underground biomass in the herb layer of upland meadow is more than that in the terrace meadow, while underground biomass in the upland shrubland is the most. The vertical distribution of underground biomass of each type is obvious as in shape of＂T＂. As to the distribution of the content of soil organic carbon in the three sample grounds, it showed that the deeper the soil the less the content of soil organic carbon. In May, unlike at terrace meadow, the underground biomass and the content of soil organic carbon in positive proportion, such revelation at upland meadow and upland shrubland is not apparent. In July, at upland meadow and terrace meadow the underground biomass and the content of soil total nitrogen in positive proportion, such revelation at upland shrubland is not apparent either.展开更多
The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the ...The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the NO-3-N content from exceeding standard. The results showed that difference of the contents of NO-3-N in groundwater from different typical planting areas was significant. The highest content of NO-3-N in underground water was 37.4 mg/L from flower-growing region, then 22. 3 mg/L from maize-growing region, 21.9 mg/L from vegetable-growing region, and the lowest content of NO-3-N in underground water was 19.2 mg/L from rice-growing region. Except rice-growing region, the contents of NO-3-N in underground water of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12.5%-87.5%, 9.4%-75.5%, 17.9%-58.9% and 21.4%-96.0% of the samples were exceeding standard limit in maize growing region, rice-growing region, vegetable-growing region and flower-growing region. The contents of NO-3-N in under-groundwater before the rainy season was higher than that of NO-3-N in under-groundwater after the rainy season at the same depth of the well.展开更多
Directive(EU)2017/164 establishes a fourth list of indicative occupational exposure limit values(IOELVs)to protect workers from risks of exposure to hazardous chemicals.It states that in underground mining and tunnell...Directive(EU)2017/164 establishes a fourth list of indicative occupational exposure limit values(IOELVs)to protect workers from risks of exposure to hazardous chemicals.It states that in underground mining and tunnelling,Member States may benefit from a transitional period regarding IOELVs for nitrogen monoxide,nitrogen dioxide,and carbon monoxide,during which the existing established IOELVs may be applied.The European Advisory Committee on Health and Safety at Work questions the technical feasibility of the proposed IOELVs in underground mining(CO,NO and NO2)and tunnelling(NO and NO2).Challenges arise concerning the availability of measurement methodologies for compliance with proposed IOELVs(NO2)in underground mining and tunnelling environments.展开更多
[Objective]The aim of this study was to reveal the relationship between the reed and salinity in severely salinized area,so as to making clear the vertical distribution of underground biomass of reed.[Method]Field inv...[Objective]The aim of this study was to reveal the relationship between the reed and salinity in severely salinized area,so as to making clear the vertical distribution of underground biomass of reed.[Method]Field investigation and sampling method were used to get the mass accurate data of underground biomass of reed.further its vertical distribution was analyzed using combined statistical and ecological method.Moreover,the C/N ratio was obtained by measuring the contents of organic carbon and nitrogen in reed wetland soil.The correlation model among organic carbon,nitrogen of reed wetlands and C/N were finally analyzed.[Result]Total underground biomass of reed population is concentrated at 10 to 40 cm underground soil layer.Thick root plays crucial role in the composition of reed total biomass,Overall change of organic carbon and total nitrogen shows a declining trend.The content of organic carbon and nitrogen in soils becpmes stable below 50 cm from the surface.The content of organic carbon in soil is positively correlated with total nitrogen in soil at significant level.[Conclusion]These results provided theoretical basis for revealing underground biomass of reed in salinized area of arid region.展开更多
基金the key Item of Sichuan Education Depart-ment (2006A070)
文摘This article, by combining field investigation with laboratorial analysis, studies diverse alpine meadow at the Eastern Margin of the Qinghai-Tibet Plateau for the underground biomass dynamics, vertical distribution of the content of soil carbon and nitrogen, the connection between the biomass and the content of carbon and nitrogen. The studies show that underground biomass in the herb layer of upland meadow is more than that in the terrace meadow, while underground biomass in the upland shrubland is the most. The vertical distribution of underground biomass of each type is obvious as in shape of＂T＂. As to the distribution of the content of soil organic carbon in the three sample grounds, it showed that the deeper the soil the less the content of soil organic carbon. In May, unlike at terrace meadow, the underground biomass and the content of soil organic carbon in positive proportion, such revelation at upland meadow and upland shrubland is not apparent. In July, at upland meadow and terrace meadow the underground biomass and the content of soil total nitrogen in positive proportion, such revelation at upland shrubland is not apparent either.
基金Supported by Agricultural Eco-environment Protection Program of Ministry of Agriculture(2110402-201258)~~
文摘The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the NO-3-N content from exceeding standard. The results showed that difference of the contents of NO-3-N in groundwater from different typical planting areas was significant. The highest content of NO-3-N in underground water was 37.4 mg/L from flower-growing region, then 22. 3 mg/L from maize-growing region, 21.9 mg/L from vegetable-growing region, and the lowest content of NO-3-N in underground water was 19.2 mg/L from rice-growing region. Except rice-growing region, the contents of NO-3-N in underground water of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12.5%-87.5%, 9.4%-75.5%, 17.9%-58.9% and 21.4%-96.0% of the samples were exceeding standard limit in maize growing region, rice-growing region, vegetable-growing region and flower-growing region. The contents of NO-3-N in under-groundwater before the rainy season was higher than that of NO-3-N in under-groundwater after the rainy season at the same depth of the well.
文摘Directive(EU)2017/164 establishes a fourth list of indicative occupational exposure limit values(IOELVs)to protect workers from risks of exposure to hazardous chemicals.It states that in underground mining and tunnelling,Member States may benefit from a transitional period regarding IOELVs for nitrogen monoxide,nitrogen dioxide,and carbon monoxide,during which the existing established IOELVs may be applied.The European Advisory Committee on Health and Safety at Work questions the technical feasibility of the proposed IOELVs in underground mining(CO,NO and NO2)and tunnelling(NO and NO2).Challenges arise concerning the availability of measurement methodologies for compliance with proposed IOELVs(NO2)in underground mining and tunnelling environments.
基金Supported by Land Use and Sustainable Development Research on Tarim Euphrates Poplar National Nature Reserve of Tarim Lake in Xinjiang(I/78636)~~
文摘[Objective]The aim of this study was to reveal the relationship between the reed and salinity in severely salinized area,so as to making clear the vertical distribution of underground biomass of reed.[Method]Field investigation and sampling method were used to get the mass accurate data of underground biomass of reed.further its vertical distribution was analyzed using combined statistical and ecological method.Moreover,the C/N ratio was obtained by measuring the contents of organic carbon and nitrogen in reed wetland soil.The correlation model among organic carbon,nitrogen of reed wetlands and C/N were finally analyzed.[Result]Total underground biomass of reed population is concentrated at 10 to 40 cm underground soil layer.Thick root plays crucial role in the composition of reed total biomass,Overall change of organic carbon and total nitrogen shows a declining trend.The content of organic carbon and nitrogen in soils becpmes stable below 50 cm from the surface.The content of organic carbon in soil is positively correlated with total nitrogen in soil at significant level.[Conclusion]These results provided theoretical basis for revealing underground biomass of reed in salinized area of arid region.
