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Land degradation is a global development and environment issue that afflicts China more than most countries in terms of the extent, economic impact, and number of people affected. Up-to-date, quantitative information is needed to support policy and action for food and water security, economic development, and environmental integrity. Data for a defined, recent period enable us to distinguish the legacy of historical land degradation from what is happening now. We define land degradation as long-term decline in ecosystem function and productivity and measure it by remote sensing of the normalized difference vegetation index (NDVI), the greenness index. NDVI may be translated to net primary productivity (NPP). Deviation from the norm serves as a proxy assessment of land degradation and improvement--if other factors that may be responsible are taken into account. These other factors include climate, which may be assessed by rain- use efficiency and energy-use efficiency. Analysis of the 23-year Global Inventory Modeling and Mapping Studies (GIMMS) NDVI data reveals that, in China over the period 1981-2003, NPP increased overall, but areas of declining climate-adjusted NPP comprise 23% of the country, mainly in south China. About 35% of China's population (457 million out of 1 317 million) depend on the degrading land. Degrading areas suffered a loss of NPP of 12 kgC ha-1 y-1 , amounting to almost 60 million tC not fixed from the atmosphere; loss of soil organic carbon from these areas is likely to be orders of magnitude greater. There is no correlation between land degradation and dry lands; it is more of an issue in cropland and forest: 21% of degrading land is cropland and 40% is forest, 24% of the arable and 44% of the forest, respectively. There is no simple statistical relationship between land degradation and rural population density or poverty. Most identified land degradation is in the south and east, driven by unprecedented land-use change. [ABSTRACT FROM AUTHOR]

It is necessary to understand the aquatic chemical characteristics of natural surface fresh water for water quality assessment. The chemical data from different kinds of water in the central Guizhou karst area showed that spring water from carbonate rock cracks (crack-water) is of neutrality or meta-alkalinity and [C] Ca II type. The amounts of all ions and the concentrations of HCO and Ca2+ were higher in the autumn than in the spring, the crack-water was influenced by the infiltration of surface water in the process of erosion and/or transportation with decreasing HCO and increasing pH, SO, Cl-, K+ and Na+ during running in a certain distance on the land surface. In particular, the chemical compositions of the waters at Tianxingqiao (upper-stream), Shuiliandong (mid-waterfall) and Luoshuitan (down-pool) near the Huangguoshu Waterfall were much different from those of the crack-water. The concentrations of SO, Na+, Fe3+ and NO varied closely with seasons. The CaCO3 deposited violently with CO2 release in the spring. In Lake Hongfeng the HCO /SO equivalent ratios were only 2.1–2.4, but Ca2+ /Mg2+ up to 2.4-4.2. The Cl- concentration increased by a factor of 1 and Na+ by order of magnitude relative to the spring water. These indicated the increase in artificial pollutant discharge in the Lake Hongfeng watershed. In addition, porewater in the soils covering carbonate rocks belongs to strongly mineralized water. The obvious differences in water quality were controlled by carbonate deposition, sulphate mineralization and nitrogen fixation as well as ammonification. It is indicated that the chemical compositions in the waters from the karst region were unstable and changeable. [ABSTRACT FROM AUTHOR]

Water quality of Lake Baihua was found worsening in the autumn of 1994. Studies have shown that the decomposition of organic matter in the upper-level sediments resulted in seasonal anoxia with the release of P, Mn, and S from the sediments to the overlying water column, and the increase of NO concentration led to blackening of the water column, death of fishes and secondary Mn pollution. [ABSTRACT FROM AUTHOR]

Focuses on a study on fallout radionuclides (beryllium and cesium) in surface soils and lake sediments in west Yunnan and central Guizhou, China. Methodology of the study; Results and discussion; Conclusion.

Focuses on a study of the geochemical records of carbon in sediments of Erhai Lake, China and the implication of effects of the Himalayas uplift on global environmental changes. Methodology of the study; Results and discussion; Conclusion.