Urban development in arid and semi-arid regions is largely constrained by fragile physical environ- ments. The characteristics of an urban settlement are different from those in other regions of China. This paper anal...Urban development in arid and semi-arid regions is largely constrained by fragile physical environ- ments. The characteristics of an urban settlement are different from those in other regions of China. This paper analyses the coupling characteristics and spatio-temporal variations for oasis urban development and water-land resources at the northern slopes of the Tianshan Mountains by principal component analysis and a coupling degree model. The result shows that the degree and change in regional use of water and land resources are different among the studied cities/counties during their development. The built-up areas of these cities/counties have changed little with increasing populations and urbanization levels, which well reflects that the urban development in arid and semi-arid regions is limited by oasis areas. Per capita amount of water supplied, however, presented a trend of slowed growth with increasing levels of urbanization. Water consumption gradually increased with urban development and the improvement of people＇s living standards, accompanied by enhanced water use efficiency. The level of urbanization can be assessed through the coupling degree between oasis urban development and the use of water and land resources. A high coupling degree represents a high level of comprehensive urban devel- opment and use of water-land resources. Alternatively, a low coupling degree denotes a low level of urban devel- opment and water-land resource use.展开更多
Exploring the utilization effect of water-land resources under the evolution of dietary patterns is of great significance in achieving sustainable global food consumption and the effective allocation of national resou...Exploring the utilization effect of water-land resources under the evolution of dietary patterns is of great significance in achieving sustainable global food consumption and the effective allocation of national resources.Our selected study area was China,a country with rapidly changing dietary consumption patterns,and the research period was between 1987 and 2020.Based on the material called Chinese Dietary Guidelines 2021,this study introduced the“virtual water”and the“virtual land”to quantify the utilization effect of water-land resources under the evolution of Chinese dietary patterns.Results showed that the dietary patterns gradually changed from“cereal-vegetable-based consumption”to“diversified consumption”.Food consumption’s total water footprint(WF)increased from 471.1 Gm3in 1987 to 848.8 Gm3in 2020,with a growth rate of 80.2%.Moreover,the total land requirement for food(LRF)increased from 88.8 Mha in 1987 to 129.9 Mha in 2020,with a growth rate of 46.3%.Furthermore,the meat consumption was the major contributor to the increase in total WF(104.0%)and LRF(102.1%).In contrast to the balanced diet pattern,there was no waste of water-land resources consumption for the food consumption of urban-rural residents in China between 1987 and 2020.However,the consumption of water resources would gradually approach the resource cost under the balanced diet patterns.It would eventually break through the critical value and reach the state of resource waste.In addition,the findings showed that urban residents’waste rate of water-land resources for meat consumption increased by 142.3%compared with that in 1987.The research results can provide scientific guidance for resolving the food crisis under the supply of water-land resources in China and have an essential reference for national food security and sustainable development of resources and environment.展开更多
基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、...基于检索1950-2016年发表在中国知网、Google Scholar、Web of Science等数据库的文章,筛选出关于我国退耕还草工程与土壤有机碳的文献123篇(126个研究地点)。基于筛选文献,提取了农田和恢复草地的土壤有机碳含量、土壤有效养分含量、恢复时间和气候等数据735条,旨在探究我国退耕还草工程对土壤有机碳含量的影响及其主导因素。结果表明:1)农田恢复为草地后,土壤有机碳含量呈先下降后上升趋势(时间拐点约为第6年),整体上退耕还草工程使土壤有机碳含量提高了19.8%。2)土壤有机碳的正响应随土壤深度增加而减弱,且深度超过1 m时其正响应不明显。3)土壤有效氮是影响土壤有机碳恢复的主要因素,而土壤有效磷和植物功能群对其影响不大。4)沿着增加的水分梯度,土壤有机碳的恢复效果由负变正,转变阈值为25.15 (干旱指数)。总体而言,我国退耕还草工程对土壤有机碳含量的影响为正效应,此效应受环境梯度和恢复时间的共同影响。本研究能够为我国土地利用变化背景下土壤碳库管理的相关决策提供科学依据。展开更多
基金supported by the Dr.Western-funded Projects of Chinese Academy of Sciences(XBBS200805)the National Natural Science Foundation of China(40901092)
文摘Urban development in arid and semi-arid regions is largely constrained by fragile physical environ- ments. The characteristics of an urban settlement are different from those in other regions of China. This paper analyses the coupling characteristics and spatio-temporal variations for oasis urban development and water-land resources at the northern slopes of the Tianshan Mountains by principal component analysis and a coupling degree model. The result shows that the degree and change in regional use of water and land resources are different among the studied cities/counties during their development. The built-up areas of these cities/counties have changed little with increasing populations and urbanization levels, which well reflects that the urban development in arid and semi-arid regions is limited by oasis areas. Per capita amount of water supplied, however, presented a trend of slowed growth with increasing levels of urbanization. Water consumption gradually increased with urban development and the improvement of people＇s living standards, accompanied by enhanced water use efficiency. The level of urbanization can be assessed through the coupling degree between oasis urban development and the use of water and land resources. A high coupling degree represents a high level of comprehensive urban devel- opment and use of water-land resources. Alternatively, a low coupling degree denotes a low level of urban devel- opment and water-land resource use.
基金National Natural Science Foundation of China,No.42171230,No.42071170。
文摘Exploring the utilization effect of water-land resources under the evolution of dietary patterns is of great significance in achieving sustainable global food consumption and the effective allocation of national resources.Our selected study area was China,a country with rapidly changing dietary consumption patterns,and the research period was between 1987 and 2020.Based on the material called Chinese Dietary Guidelines 2021,this study introduced the“virtual water”and the“virtual land”to quantify the utilization effect of water-land resources under the evolution of Chinese dietary patterns.Results showed that the dietary patterns gradually changed from“cereal-vegetable-based consumption”to“diversified consumption”.Food consumption’s total water footprint(WF)increased from 471.1 Gm3in 1987 to 848.8 Gm3in 2020,with a growth rate of 80.2%.Moreover,the total land requirement for food(LRF)increased from 88.8 Mha in 1987 to 129.9 Mha in 2020,with a growth rate of 46.3%.Furthermore,the meat consumption was the major contributor to the increase in total WF(104.0%)and LRF(102.1%).In contrast to the balanced diet pattern,there was no waste of water-land resources consumption for the food consumption of urban-rural residents in China between 1987 and 2020.However,the consumption of water resources would gradually approach the resource cost under the balanced diet patterns.It would eventually break through the critical value and reach the state of resource waste.In addition,the findings showed that urban residents’waste rate of water-land resources for meat consumption increased by 142.3%compared with that in 1987.The research results can provide scientific guidance for resolving the food crisis under the supply of water-land resources in China and have an essential reference for national food security and sustainable development of resources and environment.
