Dynamics of wetlands and their effects on carbon emissions in China coastal region - Case study in Bohai Economic Rim

Wetlands are one of the largest carbon sinks in the world due to their large carbon storage, potential for carbon sequestration in peat formation, sediment deposition and plant biomass. However, rapid economic development is causing changes to wetland carbon storage. China has participated in the implementation of the Kyoto Protocol and is decreasing its carbon emissions. Analyzing the carbon changes that are caused by wetland dynamics may provide some insights regarding decreasing carbon emissions. Therefore, wetland data from 1985, 1995 and 2005 were extracted from remote sensing images. Using spatial analysis and statistics, we determined that the water body area continued to increase, whereas the swamp, floodplain and shallow areas tended to decrease during the period from 1985 to 2005. Those changes caused wetland carbon stock to decrease. The conversion of other land use categories to wetland was the primary cause of carbon stock loss. Therefore, it is more beneficial for China to decrease per capita carbon emissions by decreasing carbon emissions from the conversion of other land use categories to wetlands. (C) 2013 Elsevier Ltd. All rights reserved.Wetlands are one of the largest carbon sinks in the world due to their large carbon storage, potential for carbon sequestration in peat formation, sediment deposition and plant biomass. However, rapid economic development is causing changes to wetland carbon storage. China has participated in the implementation of the Kyoto Protocol and is decreasing its carbon emissions. Analyzing the carbon changes that are caused by wetland dynamics may provide some insights regarding decreasing carbon emissions. Therefore, wetland data from 1985, 1995 and 2005 were extracted from remote sensing images. Using spatial analysis and statistics, we determined that the water body area continued to increase, whereas the swamp, floodplain and shallow areas tended to decrease during the period from 1985 to 2005. Those changes caused wetland carbon stock to decrease. The conversion of other land use categories to wetland was the primary cause of carbon stock loss. Therefore, it is more beneficial for China to decrease per capita carbon emissions by decreasing carbon emissions from the conversion of other land use categories to wetlands. (C) 2013 Elsevier Ltd. All rights reserved

Shape-related optical and catalytic properties of wurtzite-type CoO nanoplates and nanorods

National Basic Research Program of China [2012CB933103]; National Outstanding Youth Science Foundation of China [50825101]; National Natural Science Foundation of China [51171157, 51171158]In this paper, we report the anisotropic optical and catalytic properties of wurtzite-type hexagonal CoO (h-CoO) nanocrystals, an unusual nanosized indirect semiconductor material. h-CoO nanoplates and nanorods with a divided morphology have been synthesized via facile solution methods. The employment of flash-heating and surfactant tri-n-octylphosphine favors the formation of plate-like morphology, whereas the utilization of cobalt stearate as a precursor is critical for the synthesis of nanorods. Structural analyses indicate that the basal plane of the nanoplates is (001) face and the growth direction of the nanorods is along the c axis. Moreover, the UV-vis absorption spectra, the corresponding energy gap and the catalytic properties are found to vary with the crystal shape and the dimensions of the as-prepared h-CoO nanocrystals. Furthermore, remarkable catalytic activities for H-2 generation from the hydrolysis of alkaline NaBH4 solutions have been observed for the as-prepared h-CoO nanocrystals. The calculated Arrhenius activation energies show a decreasing trend with increasing extension degree along the direction, which is in agreement with the variation of the charge-transfer energy gap. Finally the maximum hydrogen generation rate of the h-CoO nanoplates exceeds most of the reported values of transition metal or noble metal containing catalysts performing in the same reaction system, which makes them a low-cost alternative to commonly used noble metal catalysts in H-2 generation from the hydrolysis of borohydrides, and might find potential applications in the field of green energy

A facile approach to fabrication of well-dispersed NiO-ZnO composite hollow microspheres

A novel, facile and template-free approach was developed for the fabrication of amorphous zinc-nickel citrate hollow microspheres and crystalline well-dispersed NiO-ZnO composite hollow microspheres. In this approach, amorphous zinc-nickel citrate hollow microspheres were prepared through a simple chemical reaction and with room temperature ageing at nickel nitrate solution. The zinc-nickel citrate hollow microspheres have an average size of about 1.4 μm. The average thickness of the shell is about 300 nm. The content of Ni in the zinc-nickel citrate can be simply adjusted by changing the ageing time. The well-dispersed NiO-ZnO composite hollow microspheres can be prepared via the perfect morphology inheritance of the zinc-nickel citrate hollow microspheres, by calcination at 500 °C for 2 h. The optical absorption of the samples can extend into the visible region after the loading of NiO. The NiO-ZnO composite hollow microspheres with the high content of NiO exhibit the highest photocatalytic activity for the degradation of different organic dyes including Rhodamine-B, methylene blue and methyl orange under UV irradiation, which might be ascribed to their highest separation efficiency of photogenerated electron-hole pairs. In addition, these NiO-ZnO composite photocatalysts can be used repeatedly without a significant decrease of the photocatalytic activity under UV irradiation. ? 2013 The Royal Society of Chemistry

Influences of the Grain-for-Green project on grain security in southern China

Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis is performed to analyze the possible loss of grain production if cropland under different degrees of soil erosion is exposed to the Grain-for-Green project. The projected total grain production on the basis of the 2000 grain production data in south China will decrease by 7.77% if cultivation is stopped on the cropland with high, very high, severe and very severe erosion, which, although not affects the grain security in southern China, would damage the grain security for the whole China. However, if all cropland on slopes above 25 is converted to forest or grassland, grain production will decrease by 2.1%. If all cropland covered with high, very high, severe and very severe erosion on slopes above 25 is converted to forest or grassland, grain production will decrease by 0.91%. Neither of the two measures will damage grain security in southern China, nor the whole China. So, the government should continue the Grain-for-Green project based on both slope and soil erosion degrees to ensure the grain security and reduce soil erosion at the same time. Published by Elsevier Ltd.Ensuring grain security has always been a top priority in China. As one of the major grain production areas in China, southern China is currently being criticized for the urban encroachment on prime agricultural land and decrease in grain production due to Grain-for-Green project. Based on the erosion pattern from the RUSLE model, spatial analysis is performed to analyze the possible loss of grain production if cropland under different degrees of soil erosion is exposed to the Grain-for-Green project. The projected total grain production on the basis of the 2000 grain production data in south China will decrease by 7.77% if cultivation is stopped on the cropland with high, very high, severe and very severe erosion, which, although not affects the grain security in southern China, would damage the grain security for the whole China. However, if all cropland on slopes above 25 is converted to forest or grassland, grain production will decrease by 2.1%. If all cropland covered with high, very high, severe and very severe erosion on slopes above 25 is converted to forest or grassland, grain production will decrease by 0.91%. Neither of the two measures will damage grain security in southern China, nor the whole China. So, the government should continue the Grain-for-Green project based on both slope and soil erosion degrees to ensure the grain security and reduce soil erosion at the same time. Published by Elsevier Ltd

A Research to Village Combination and the Analysis of the Influences of Which Having on Social Economy During the Urbanization Process of Yantai City

With the rapid development of urbanization of our country, serious conflicts on land using appear. Village combination in rural areas is an important way to increase cultivated land, promote the development of urbanization and effectively solve conflicts on land using, which plays an significant role in solving agriculture problems, countryside problems and peasant problems, assuring foods safety and constructing social new countryside.Taking Yantai City as example, the paper firstly makes analyses on the necessaries and the feasibility of village combination. And then based on the mode GM (1,1) of grey theory, the paper forecasts the urbanization ratio, the proportion of urban and rural areas to the whole population and finally programs the rational scale of central villages and towns of Yantai City. At last, the paper conducts a detailed analysis on the social economic influence of village combination of Yantai City, pointing out that village combination affords carriers to farmers citizenization and it is beneficial to explore the new mode of rural urbanization, which is the engine of economic development in China

Fragmentation effects of oil wells and roads on the Yellow River Delta, North China

Oil exploitation and road development have strongly fragmented the coastal landscapes, leading to profound ecological consequences. The dynamic relationships between oil wells, roads, and landscape fragmentation indices in the Yellow River Delta, China were explored. Oil wells, roads and land cover were mapped from TM images in 1992, 2000, 2006, and 2009, respectively. Changes and relationships were compared among three selected typical sections using linear regression models. We also evaluated the fragmentation effects of oil exploitation on protected wetlands in the Yellow River Delta Natural Reserve (NR). The results showed that oil wells and roads increased greatly. Oil well density and road length density were positively related to patch number and negatively related to patch shape indices. Both drivers have cumulative effects on landscape fragmentation. Influences of old oil wells and roads were stronger than those of new ones. Current management strategies of the NR have failed to effectively prohibit the disturbances of oil activities at the regional scale. The ecological function of protected wetland systems has been damaged by the increase of oil wells. Therefore, based on the principles of landscape ecology, effective approaches were proposed to minimize the negative effects of oil exploitation on the coastal area. (C) 2010 Elsevier Ltd. All rights reserved.Oil exploitation and road development have strongly fragmented the coastal landscapes, leading to profound ecological consequences. The dynamic relationships between oil wells, roads, and landscape fragmentation indices in the Yellow River Delta, China were explored. Oil wells, roads and land cover were mapped from TM images in 1992, 2000, 2006, and 2009, respectively. Changes and relationships were compared among three selected typical sections using linear regression models. We also evaluated the fragmentation effects of oil exploitation on protected wetlands in the Yellow River Delta Natural Reserve (NR). The results showed that oil wells and roads increased greatly. Oil well density and road length density were positively related to patch number and negatively related to patch shape indices. Both drivers have cumulative effects on landscape fragmentation. Influences of old oil wells and roads were stronger than those of new ones. Current management strategies of the NR have failed to effectively prohibit the disturbances of oil activities at the regional scale. The ecological function of protected wetland systems has been damaged by the increase of oil wells. Therefore, based on the principles of landscape ecology, effective approaches were proposed to minimize the negative effects of oil exploitation on the coastal area. (C) 2010 Elsevier Ltd. All rights reserved

Classification and Estimation of Irrigation Waters Based on Remote Sensing Images: Case Study in Yucheng City (China)

The downstream plain of the Yellow River is experiencing some of the most severe groundwater depletion in China. Although the Chinese government has issued policies to ensure that the Yellow River can provide enough irrigation waters for this region, groundwater levels continue to decrease. Yucheng City was selected as a case study. A new method was designed to classify the cropland into various irrigated cropland. Subsequently, we analyzed data regarding these irrigated-cropland categories, irrigation norms, and the minimum amount of irrigation water being applied to cropland. The results showed that 91.5% of farmland can be classified as double irrigated (by both canal/river and well water), while 8.5% of farmland can be classified as well irrigated. During the irrigation season, the sediments brought in by the river have blocked portions of the canals. This has led to 23% of the double-irrigated cropland being irrigated by groundwater, and it is thus a main factor causing reductions in groundwater supply. These blocked canals should be dredged by local governments to mitigate local groundwater depletion. The method for classifying irrigated cropland from high-resolution images is valid and it can be used in other irrigated areas with a declining groundwater table for the sustainable use of groundwater resources

Evaluating the Effects of Government Policy and Drought from 1984 to 2009 on Rangeland in the Three Rivers Source Region of the Qinghai-Tibet Plateau

The Three Rivers Source Region of the Qinghai-Tibet Plateau is a key area that has extensive impacts on much of the population and economy of China as well as several Southeast Asian countries. The rangeland in this area has undergone degradation, the driving factors of which have been extensively investigated in previous studies. However, the effect of policy on rangeland was not analyzed by subdividing the study period according to the timing of the rangeland policies. The role of dry conditions during the process of degradation has not been studied. Therefore, the period from 1984 to 2009 was subdivided into five periods according to the timing of the relevant government policies based on long-term field investigation. The mean annual normalized difference vegetation index (NDVI) and its relationship to dry conditions, policy, temperature, precipitation, and moisture index were analyzed for the five periods. According to our analysis, dry conditions mainly occurred in non-vegetation-growing months, and they did not affect the status of the rangeland. The privatization of rangeland and livestock caused the number of livestock to increase, resulting in a decrease in the mean annual NDVI from 1984 to 1993. The policies of "Green-to-Grain" and eco-migration caused livestock numbers to decrease and the NDVI to increase after 1994. Physical factors such as temperature, precipitation, and moisture also affected the status of the rangeland. Increased temperature had positive effects on rangeland in most areas, but its effect was offset by increased numbers of livestock from 1984 to 1993. Precipitation had positive effects only in drier areas in which the precipitation in the vegetation-growing months was less than 400 mm. In general, the policies of "Green-to-Grain" and eco-migration improved the status of rangeland, and helped improve sustainable use of the rangeland. The methods used in this study could be applied to other case studies of rangeland. Governments should continue to implement compensation policies to maintain the improved condition of rangeland in the area and expand those policies to other rangeland areas