To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-far...To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail.展开更多
Climate change has substantially impacted crop growth and development in the northern agro-pastoral transitional zone. Examination of the response of crop water consumption to climate change may provide a guide for ad...Climate change has substantially impacted crop growth and development in the northern agro-pastoral transitional zone. Examination of the response of crop water consumption to climate change may provide a guide for adapting local agricultural production and ecological construction to new realities. The water consumption of three local crops （wheat, naked oats, and potatoes） is examined for Wuchuan County in the northern agro-pastoral transitional zone of China using meteorological data from 1960 to 2007 and soil moisture data from 1983 to 2007. The relationships between climate change and the crop water consumption are discussed. The results show that Wuchuan experienced both a warming trend and a reduction of precipitation between 1960 and 2007. The annual mean surface air temperature increased at a rate of 0.04℃ yr-1 and the annual precipitation decreased at a rate of 0.7 mm yr-1 . Both trends are particularly pronounced between 1983 and 2007, with an increase in annual mean temperature of 0.09℃ yr-1 and a decrease in annual mean precipitation of 2.1 mm yr-1 . Crop water consumption decreased between 1983 and 2007 for wheat （1.65 mm yr-1 ）, naked oats （2.04 mm yr-1 ）, and potatoes （3.85 mm yr-1 ）. Potatoes and naked oats consume more water than wheat. Climate change has significantly impacted crop water consumption. Water consumption and rainfall during the growing season are positively correlated, while water consumption and active accumulated temperature are negatively correlated. Compared to precipitation, accumulated temperature has little impact on crop water consumption. Recent climate change has been detrimental for crop production in Wuchuan County. Adaptation to climate change should include efforts to breed drought-resistant crops and to develop drought-resistant cultivation techniques.展开更多
Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pat...Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pattern evolution over this 10-year period and built a land-use pattern simulation model, based on which land-use pattern evolution and optimization modeling in this region were studied. Results showed that the proposed model can effectively simulate regional land-use patterns and help improve regional ecological environments.展开更多
Elemental sulfur(ES) is one of the intermediates in the inorganic sulfur cycle and thus plays a key role in the fractionation of stable sulfur isotopes in different reservoirs and the marine environment. In this study...Elemental sulfur(ES) is one of the intermediates in the inorganic sulfur cycle and thus plays a key role in the fractionation of stable sulfur isotopes in different reservoirs and the marine environment. In this study, solid ES is discovered in sediments near the Jiulong Methane Reef in the northern South China Sea by scanning electron microscopy and Raman spectroscopy. Combining the morphology and distribution of ES, pyrite concentrations, and sulfur isotopes, we conclude that:(1) solid ES coexists with pyrite microcrystals and sulfide(oxyhydr)oxides as well as clay minerals, and they are mainly distributed on the surface of mineral aggregates;(2) ES mainly occurs within and near the sulfate-methane transition zone(SMTZ) despite little morphological diversity;(3) ES formation might be related to hydrogen sulfide oxidation and is therefore linked with fluctuations in the SMTZ. Within the SMTZ, hydrogen sulfide is produced and pyrite precipitates because of enhanced anaerobic oxidation of methane coupled with dissimilatory sulfate reduction. This enhances the efficiency of the inorganic sulfur cycle and provides favorable conditions for ES formation. The discovery of solid ES in sediments near the Jiulong Methane Reef suggests an important relationship with SMTZ fluctuations that could have implications for the evolution of methane hydrate in the South China Sea.展开更多
文摘To provide materials for the selection of plant species for vegetation restoration and reconstruction in the farming-pastoral zone in northern China, where the eco-environment has been already deteriorated by over-farming and over-grazing, the suitable trees, shrubs and herbages were examined, screened and identified under the guidance of four principles of taking precedence for ecological conservation, being beneficial to economic production, matching species (trees, shrubs and herbages) with the site, and giving consideration to the integrity of local administrative division. According to the key ecological factors that determine species growth and distribution in the zone, i.e., the lowest daily mean temperature in a year, annual accumulated temperature, and water regimes represented by the moist index, the ratio between annual rainfall and accumulated temperature (>0 degreesC), as well as the soil type influenced by climate, surface substances and landform, the farming-pastoral zone was regionalized into seven parts: ( I) Western Songliao Plain and Da Hinggan Mountain Region; (II) Upper Liaohe River Sandy Region; (III) Mid-Eastern Nei Mongol Plateau and Northwestern Heibei Mountain Region; (IV) Luliang, Taihang and Yanshan Mountain Region; ( V) Ordos Plateau Sandy Region; (VI) Northern Shaanxi to Eastern Gansu Loess Plateau Region; and (VII) Mid Gansu to Eastern Qinghai Plateau Loess Region. And the suitable trees, shrubs and herbages for each region were selected and tabularly introduced in detail.
基金Supported by the National Basic Research and Development (973) Program of China (2012CB956200)National Natural Science Foundation of China (41271110)National Science and Technology Support Program of China (2012BAD09B00)
文摘Climate change has substantially impacted crop growth and development in the northern agro-pastoral transitional zone. Examination of the response of crop water consumption to climate change may provide a guide for adapting local agricultural production and ecological construction to new realities. The water consumption of three local crops （wheat, naked oats, and potatoes） is examined for Wuchuan County in the northern agro-pastoral transitional zone of China using meteorological data from 1960 to 2007 and soil moisture data from 1983 to 2007. The relationships between climate change and the crop water consumption are discussed. The results show that Wuchuan experienced both a warming trend and a reduction of precipitation between 1960 and 2007. The annual mean surface air temperature increased at a rate of 0.04℃ yr-1 and the annual precipitation decreased at a rate of 0.7 mm yr-1 . Both trends are particularly pronounced between 1983 and 2007, with an increase in annual mean temperature of 0.09℃ yr-1 and a decrease in annual mean precipitation of 2.1 mm yr-1 . Crop water consumption decreased between 1983 and 2007 for wheat （1.65 mm yr-1 ）, naked oats （2.04 mm yr-1 ）, and potatoes （3.85 mm yr-1 ）. Potatoes and naked oats consume more water than wheat. Climate change has significantly impacted crop water consumption. Water consumption and rainfall during the growing season are positively correlated, while water consumption and active accumulated temperature are negatively correlated. Compared to precipitation, accumulated temperature has little impact on crop water consumption. Recent climate change has been detrimental for crop production in Wuchuan County. Adaptation to climate change should include efforts to breed drought-resistant crops and to develop drought-resistant cultivation techniques.
文摘Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pattern evolution over this 10-year period and built a land-use pattern simulation model, based on which land-use pattern evolution and optimization modeling in this region were studied. Results showed that the proposed model can effectively simulate regional land-use patterns and help improve regional ecological environments.
基金supported by the National Natural Science Foundation of China(Grants Nos.41472085 and 41172102)the National Basic Research Program of China(Grants Nos.2011CB808805 and 2009CB21950605)the National Project of Exploration and Test Production for Gas Hydrate(Grants Nos.GZH20110030-50603 and GZH20110030-6WX02)
文摘Elemental sulfur(ES) is one of the intermediates in the inorganic sulfur cycle and thus plays a key role in the fractionation of stable sulfur isotopes in different reservoirs and the marine environment. In this study, solid ES is discovered in sediments near the Jiulong Methane Reef in the northern South China Sea by scanning electron microscopy and Raman spectroscopy. Combining the morphology and distribution of ES, pyrite concentrations, and sulfur isotopes, we conclude that:(1) solid ES coexists with pyrite microcrystals and sulfide(oxyhydr)oxides as well as clay minerals, and they are mainly distributed on the surface of mineral aggregates;(2) ES mainly occurs within and near the sulfate-methane transition zone(SMTZ) despite little morphological diversity;(3) ES formation might be related to hydrogen sulfide oxidation and is therefore linked with fluctuations in the SMTZ. Within the SMTZ, hydrogen sulfide is produced and pyrite precipitates because of enhanced anaerobic oxidation of methane coupled with dissimilatory sulfate reduction. This enhances the efficiency of the inorganic sulfur cycle and provides favorable conditions for ES formation. The discovery of solid ES in sediments near the Jiulong Methane Reef suggests an important relationship with SMTZ fluctuations that could have implications for the evolution of methane hydrate in the South China Sea.
