The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining th...The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining the regional soil and water resource capacity. We used loess thickness data, a pedotransfer function for bulk density(BD), and the clay content data observed in 242 sites across the LP to derive the BD of loess and then estimate the loess mass and its distribution across the LP. The results indicated that the average BD of loess between the surface and bedrock is 1.58 g cm^(-3), varying from 1.18 to 1.87 g cm^(-3).The total loess mass is approximately 5.45 ? 10^(13) t, and the average loess mass over an area of 1 m^2 is 169 t, ranging from 1.36 to 585 t. The greatest mass of loess is in the south-central of the LP while the lowest mass of loess is in the northwest and river valley areas. Our estimate of loess mass provides key data for calculating water, carbon, and nutrient storages in the LP, which improves our understanding of soil-water processes and ecohydrological systems in this landscape.展开更多
The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into g...The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into grassland or woodland, especially the farmland in steep slope positions or far away from the river. The change of land use pattern altered the rainfall runoff and runoff sediment relationships, and led to higher slope of trend curves(STCs) of annual rainfall runoff mass curve and runoff sediment mass curve in 1990s than that in 1980s. It is implied that more soil and water loss yielded in 1990s. In order to reduce soil loss, more attentions should be paid to land use pattern and some grass or other herbaceous filter strips should be built along rivers.展开更多
采用顶空固相微萃取结合全二维气相色谱-飞行时间质谱(headspace solid-phase microextraction combined-compre-hensive two dimensional gas chromatography-time of flight mass spectrometry,HS-SPME-GC×GCTOFMS)对黄土高原产...采用顶空固相微萃取结合全二维气相色谱-飞行时间质谱(headspace solid-phase microextraction combined-compre-hensive two dimensional gas chromatography-time of flight mass spectrometry,HS-SPME-GC×GCTOFMS)对黄土高原产区赤霞珠葡萄酒中挥发性成分进行分析。结果表明:全二维气相色谱具有强分离能力、高灵敏性、高峰容量等优势,可以较为全面地对葡萄酒挥发性物质进行解析,特别是一些痕量香气化合物。通过质谱库检索及保留指数比对,在黄土高原5个小产区赤霞珠葡萄酒中共定性到600种香气化合物,其中以酯类、芳香族、萜烯类和醇类为主,分别检测到128、113、85、83种,同时还检测到醛酮类、含硫化合物、呋喃、内酯、吡嗪、挥发酸等化合物,这些物质共同作用形成了该产区葡萄酒的风味特征。此外,5个小产区葡萄酒定性到的香气化合物总数及各类别的数量则均相差不大。该研究探讨了全二维气相色谱技术在葡萄酒香气解析中的应用,同时也为深入探究黄土高原产区葡萄酒的风味特征提供基础数据与理论依据。展开更多
基金supported by the National Natural Science Foundation of China (41571130081, 41371242, 41530854)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (2017076)+1 种基金the Youth Innovation Research Team Project (LENOM2016Q0001)the Open Research Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau (A314021402-1806)
文摘The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining the regional soil and water resource capacity. We used loess thickness data, a pedotransfer function for bulk density(BD), and the clay content data observed in 242 sites across the LP to derive the BD of loess and then estimate the loess mass and its distribution across the LP. The results indicated that the average BD of loess between the surface and bedrock is 1.58 g cm^(-3), varying from 1.18 to 1.87 g cm^(-3).The total loess mass is approximately 5.45 ? 10^(13) t, and the average loess mass over an area of 1 m^2 is 169 t, ranging from 1.36 to 585 t. The greatest mass of loess is in the south-central of the LP while the lowest mass of loess is in the northwest and river valley areas. Our estimate of loess mass provides key data for calculating water, carbon, and nutrient storages in the LP, which improves our understanding of soil-water processes and ecohydrological systems in this landscape.
文摘The purpose of this article is to identify the effect of land use pattern on rainfall runoff and runoff sediment relations in Zichang Watershed of the Loess Plateau. From 1986 to 1997, many farmlands changed into grassland or woodland, especially the farmland in steep slope positions or far away from the river. The change of land use pattern altered the rainfall runoff and runoff sediment relationships, and led to higher slope of trend curves(STCs) of annual rainfall runoff mass curve and runoff sediment mass curve in 1990s than that in 1980s. It is implied that more soil and water loss yielded in 1990s. In order to reduce soil loss, more attentions should be paid to land use pattern and some grass or other herbaceous filter strips should be built along rivers.
文摘采用顶空固相微萃取结合全二维气相色谱-飞行时间质谱(headspace solid-phase microextraction combined-compre-hensive two dimensional gas chromatography-time of flight mass spectrometry,HS-SPME-GC×GCTOFMS)对黄土高原产区赤霞珠葡萄酒中挥发性成分进行分析。结果表明:全二维气相色谱具有强分离能力、高灵敏性、高峰容量等优势,可以较为全面地对葡萄酒挥发性物质进行解析,特别是一些痕量香气化合物。通过质谱库检索及保留指数比对,在黄土高原5个小产区赤霞珠葡萄酒中共定性到600种香气化合物,其中以酯类、芳香族、萜烯类和醇类为主,分别检测到128、113、85、83种,同时还检测到醛酮类、含硫化合物、呋喃、内酯、吡嗪、挥发酸等化合物,这些物质共同作用形成了该产区葡萄酒的风味特征。此外,5个小产区葡萄酒定性到的香气化合物总数及各类别的数量则均相差不大。该研究探讨了全二维气相色谱技术在葡萄酒香气解析中的应用,同时也为深入探究黄土高原产区葡萄酒的风味特征提供基础数据与理论依据。
