| 2 | China's Land Carrying Capacity Based on Man-grain Relationships显示文摘With population growth and increasing pressure on land resources,land carrying capacity(LCC) and food safety have been attracting great attention worldwide.From the point of man-grain relationship and by establishing LCC and land carrying capacity index(LCCI) models,this article firstly analyzes the spatial-temporal dynamics of LCC of China from 1949 to 2005 at county,provincial and national levels.Choosing 2005 as a representative year,this article then evaluates the LCC of 264 pastoral regions(semipastoral regions),663 urban regions and 592 poverty stricken regions of the country.The results show that:(1) from 1949 to 2005,with the increase of grain production,the LCC of China has been improved conspicuously,but due to the rapid population growth,the production can only maintain a low level grain consumption;(2) over the past 25 years(1980-2005),the number of population overloading provinces decreased from 23 to 15 and the mangrain relationship has been improved gradually,but there were more overloading provinces than surplus provinces in China;(3) at county level,there were 1572 overloading counties in 1980 accounting for 68.26% of the total counties of the country and where were 649 million people lived,while in 1990,2000 and 2005,the number of overloading counties were 1066,1133 and 1087 respectively,which shows that the man-grain relationship has been improved obviously during the past 25 years;as for spatial distribution,the surplus counties were mainly concentrated in agriculture developed regions,such as Northeast Plain,North China Plain,middle and lower Reaches of the Yangtze River Plain,and overloading counties were mainly located in regions with poor natural environment and low grain production capacity,such as Northwest China,Tibetan Plateau and Loess Plateau and economically developed urban regions,such as Beijing,Tianjin and Shanghai;(4) animal husbandry improved greatly the LCC of pastoral and semi-pastoral regions,while urban regions were overloading for increasing population pressure and more than half of poverty stricken regions were overloading due to critical natural environment and poor economic conditions. | Feng Zhiming Zhang Weike Yang Yanzhao | 2009 | Chinese Journal of Population,Resources and Environment2009，7，4： | 1 |
| 3 | Climate-induced Changes in Spring Maize Water Requirement in Xiliaohe River Watershed显示文摘Xiliaohe River watershed plays an important role in regional and national grain security.With the development of society and economy,water consumption that increased dramatically causes water shortages.Crop water requirement can provide quantitative basis for making regional irrigation scheme.In this study,spring maize water requirement is calculated by using PenmanMonteith formula and spring maize coefficient from May to September at 10 meteorological stations in Xiliaohe River watershed from 1951 to 2005.The variation trend of the spring maize water requirement during the whole growing stage,water requirement in every month,and meteorological influencing factors are obtained by using Mann-Kendall method,and the degree of grey incidence between the water requirement and meteorological influencing factors are shown.The results are the spring maize water requirement during the whole growing stages increases at half of the stations in Xiliaohe River watershed,and are remarkably affected by the water requirement in May.The monthly mean,maximum and minimum air temperature form May to September show an increasing trend in Xiliaohe River watershed in recent 55 years.The monthly mean and minimum air temperature increases notably.The relative humidity,precipitation,wind speed and sunshine show a decreasing trend with variety for different months.The monthly maximum air temperature,wind speed,sunshine and monthly mean air temperature have the highest correlation degree with spring maize water requirement from May to September. | Sun Xiaozhou Feng Zhiming Yang Yanzhao Zhang Weike | 2009 | Chinese Journal of Population,Resources and Environment2009，7，4： | 1 |
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