Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as...Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as an inadequate farming practices. In this study, yield gaps were determined by using attainable yield （Ya） as a benchmark under optimized management practices, i.e., micro-ridge and side planting with plastic-mulching （MS）, and flat planting with plastic-mulching （PM）. The yields under MS and PM modes are defined as Yal and Ya2, respectively. Under the same field with MS and PM modes but different densities and fertilizer usages and so on, it was defined as simulated farmers＇ practices. The yield of simulated farmers＇ practices （Yfl） reached 57.3 and 69.6% of Yal and Ya2, respectively, while the average yield of 298 randomly surveyed farmers （Yf2） reached only 37.0 and 47.8% of Yal and Ya2 for rain-fed potato, respectively. The gaps of water use efficiency exhibited similar pattern. Further analysis shows that improper measures in rainwater conservation and accumulation, and other management practices contributed to 18.5, 18.2, and 42.6% of yield gap between Yal and Yf2. Improper nutrition management, including overuse of nitrogen and the deficiency of phosphorus andpotassium supplication, was one of the important reasons of yield gap. The results indicate the possibilities of increasing rain-fed potato yields by optimized water and fertilizermanagements in the Yin-mountain Hilly Area.展开更多
明晰物种的潜在分布区及其与当前自然保护区的空缺,对于合理高效地开展濒危物种保护具有重要的意义。为了预测四合木(Tetraena mongolica)在当代(2020s)及未来(2060s、2100s)的分布范围,以及自然保护区对四合木的保护现状,以四合木为对...明晰物种的潜在分布区及其与当前自然保护区的空缺,对于合理高效地开展濒危物种保护具有重要的意义。为了预测四合木(Tetraena mongolica)在当代(2020s)及未来(2060s、2100s)的分布范围,以及自然保护区对四合木的保护现状,以四合木为对象,利用最大熵模型(The maximum entropy model software,MaxEnt)结合23个环境变量预测其在内蒙古自治区西鄂尔多斯与宁夏回族自治区的潜在适生区,并与当前四合木自然保护区进行了保护空缺分析。结果表明:(1)MaxEnt模型的受试者工作特征曲线下的面积为0.977,表明预测结果准确。(2)影响四合木分布的主要环境因子是最湿月降水量,其次是最干月降水量、距道路距离、等温性、最冷季平均温度、坡度。(3)研究区内四合木当前适生面积为4717 km2;2020s—2100s四合木潜在分布区退缩,并向西北部偏移。(4)基于保护空缺分析,当前仅有14.88%四合木的适宜生境位于保护区内,大面积的四合木适生区未设立自然保护区,这些地区主要集中在内蒙古乌海市和鄂尔多斯市杭锦旗。研究结果旨在为四合木保护及其自然保护区建设提供科学指导。展开更多
The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financi...The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financial development scale and financial development efficiency have the greatest impact on the income gap between urban and rural areas. By cointegration test,it is found that there is a long-term equilibrium relationship between these five variables and the income gap between urban and rural areas. We build the state-space model to research the dynamic impact of these factors on the income gap between urban and rural areas. The results show that by improving the level of urbanization,we can effectively narrow the income gap between urban and rural areas,while socio-economic development,the improvement of education level,expansion of financial development scale and financial development efficiency all significantly expand the income gap between urban and rural areas.展开更多
Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic mu...Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic music education leads to all sorts of differences, thus seriously affecting the overall improvement of quality of all people. To find out the problems and the reasons of the backward in rural basic music education, this paper makes an analysis of the differences between urban and rural basic education development through a survey and a study of basic situation in music education of urban and rural elementary school in Gaocheng, Hebei province, and then puts forward thinkings and suggestions about narrowing the urban-rural music education gap on the basis of the analysis of internal and extemal problems.展开更多
Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differen...Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differences in the rural and urban economic development in less developed areas,which are mainly reflected in the differences in per capita income,living standard,and Engel coefficient.Reasons for urban and rural economic disparity in less developed areas are analyzed.The asymmetry and immobility of rural and urban resources have objectively caused the income gap between urban and rural residents;urban industrial development,which is faster than agricultural development,has widened the income gap between urban and rural residents;and the differences in comparative labor productivity in rural and urban areas have enlarged their income gap.Countermeasures to minimize the urban and rural economic development gap are put forward,such as deepening the reform,realizing the free flow of economic resources between urban and rural areas,developing rural areas through urban development,exerting the function of urban areas in the coordinated development of urban and rural areas,paying attention to the agriculture and rural areas,and improving the comparative labor productivity of agriculture.展开更多
草地叶面积指数(Leaf area index,LAI)是天然草地的重要结构参数,能够用来监测草地的生长状况和生产力水平,对草地资源可持续利用和科学管理具有重要意义。以内蒙古锡林郭勒盟典型草原为研究对象,首先使用无人机激光雷达(Airborne light...草地叶面积指数(Leaf area index,LAI)是天然草地的重要结构参数,能够用来监测草地的生长状况和生产力水平,对草地资源可持续利用和科学管理具有重要意义。以内蒙古锡林郭勒盟典型草原为研究对象,首先使用无人机激光雷达(Airborne light detection and ranging,Air-LiDAR)草地冠层观测数据,通过解析点云数据构建冠层高度模型(Canopy height model,CHM),随后进行研究区草地冠层间隙率计算,最后基于Beer-Lambert方法进行0.05 m、0.10 m、0.15 m、0.20 m 4个不同空间分辨率采样尺度下的LAI估算,并选择CHM低值、中值、高值3个不同子区域分别进行不同冠层高度下LAI的检验和分析。结果表明:(1)草地叶面积指数与冠层高度模型数值呈正相关、与冠层间隙率呈负相关。(2)机载LiDAR草地LAI估算的最优采样尺度为0.15 m,CHM不同高度子区域LAI结果检验R^(2)和RMSE分别为:低值区为0.66和0.04;中值区为0.54和0.34;高值区为0.54和1.17,表明无人机LiDAR可捕获草地冠层观测采样存在的异质性差异分布特征。(3)不同空间分辨率0.05~0.20 m间隔采样LAI结果表明,对于CHM低值、植被分布稀疏区域不同分辨率LAI无显著空间尺度变化差异,但CHM高值、较密植被分布群落LAI会随空间分辨率表现出尺度性差异。综上所述,本研究设计完成的无人机LiDAR草地LAI估算模型,参数机理具体、流程方法可操作性强,具有较好的数值检验精度,可为激光雷达在草地植被叶面积指数遥感反演及应用提供技术参考。展开更多
基金supported by the Special Industry Foundation of Ministry of Agriculture of China (201303104)the National Natural Science Foundation of China (31360502)the China Postdoctoral Science Foundation (2015M572633XB)
文摘Yin-mountain Hilly Area is one of the ideal regions for potato （Solanum tuberosum） production in China. However, potato yield is severely limited as a result of rain-fed crop mode due to water deficiency, as well as an inadequate farming practices. In this study, yield gaps were determined by using attainable yield （Ya） as a benchmark under optimized management practices, i.e., micro-ridge and side planting with plastic-mulching （MS）, and flat planting with plastic-mulching （PM）. The yields under MS and PM modes are defined as Yal and Ya2, respectively. Under the same field with MS and PM modes but different densities and fertilizer usages and so on, it was defined as simulated farmers＇ practices. The yield of simulated farmers＇ practices （Yfl） reached 57.3 and 69.6% of Yal and Ya2, respectively, while the average yield of 298 randomly surveyed farmers （Yf2） reached only 37.0 and 47.8% of Yal and Ya2 for rain-fed potato, respectively. The gaps of water use efficiency exhibited similar pattern. Further analysis shows that improper measures in rainwater conservation and accumulation, and other management practices contributed to 18.5, 18.2, and 42.6% of yield gap between Yal and Yf2. Improper nutrition management, including overuse of nitrogen and the deficiency of phosphorus andpotassium supplication, was one of the important reasons of yield gap. The results indicate the possibilities of increasing rain-fed potato yields by optimized water and fertilizermanagements in the Yin-mountain Hilly Area.
文摘明晰物种的潜在分布区及其与当前自然保护区的空缺,对于合理高效地开展濒危物种保护具有重要的意义。为了预测四合木(Tetraena mongolica)在当代(2020s)及未来(2060s、2100s)的分布范围,以及自然保护区对四合木的保护现状,以四合木为对象,利用最大熵模型(The maximum entropy model software,MaxEnt)结合23个环境变量预测其在内蒙古自治区西鄂尔多斯与宁夏回族自治区的潜在适生区,并与当前四合木自然保护区进行了保护空缺分析。结果表明:(1)MaxEnt模型的受试者工作特征曲线下的面积为0.977,表明预测结果准确。(2)影响四合木分布的主要环境因子是最湿月降水量,其次是最干月降水量、距道路距离、等温性、最冷季平均温度、坡度。(3)研究区内四合木当前适生面积为4717 km2;2020s—2100s四合木潜在分布区退缩,并向西北部偏移。(4)基于保护空缺分析,当前仅有14.88%四合木的适宜生境位于保护区内,大面积的四合木适生区未设立自然保护区,这些地区主要集中在内蒙古乌海市和鄂尔多斯市杭锦旗。研究结果旨在为四合木保护及其自然保护区建设提供科学指导。
基金Supported by Humanities and Social Sciences Project of the Ministry of Education(10YJC790111)
文摘The increasingly widening income gap between urban and rural areas is affected by many factors. Using the stepwise regression analysis,we find that urbanization level,socio-economic development,education level,financial development scale and financial development efficiency have the greatest impact on the income gap between urban and rural areas. By cointegration test,it is found that there is a long-term equilibrium relationship between these five variables and the income gap between urban and rural areas. We build the state-space model to research the dynamic impact of these factors on the income gap between urban and rural areas. The results show that by improving the level of urbanization,we can effectively narrow the income gap between urban and rural areas,while socio-economic development,the improvement of education level,expansion of financial development scale and financial development efficiency all significantly expand the income gap between urban and rural areas.
文摘Nowadays, the development of quality education has always been attached great importance in China, of which the music education has been an important part. However, serious polarization of the urban and rural basic music education leads to all sorts of differences, thus seriously affecting the overall improvement of quality of all people. To find out the problems and the reasons of the backward in rural basic music education, this paper makes an analysis of the differences between urban and rural basic education development through a survey and a study of basic situation in music education of urban and rural elementary school in Gaocheng, Hebei province, and then puts forward thinkings and suggestions about narrowing the urban-rural music education gap on the basis of the analysis of internal and extemal problems.
文摘Taking northern Jiangsu area as an example,economic disparity between urban and rural areas is described according to the data in 2000-2009 Jiangsu Statistical Yearbook.Result shows that there are significant differences in the rural and urban economic development in less developed areas,which are mainly reflected in the differences in per capita income,living standard,and Engel coefficient.Reasons for urban and rural economic disparity in less developed areas are analyzed.The asymmetry and immobility of rural and urban resources have objectively caused the income gap between urban and rural residents;urban industrial development,which is faster than agricultural development,has widened the income gap between urban and rural residents;and the differences in comparative labor productivity in rural and urban areas have enlarged their income gap.Countermeasures to minimize the urban and rural economic development gap are put forward,such as deepening the reform,realizing the free flow of economic resources between urban and rural areas,developing rural areas through urban development,exerting the function of urban areas in the coordinated development of urban and rural areas,paying attention to the agriculture and rural areas,and improving the comparative labor productivity of agriculture.
