该文基于美国的土地评价与立地评估(land evaluation and site assessment,LESA)方法,对陕西省泾阳县耕地进行了定级研究。把整个定级过程分为两个部分,前一部分为土地的自然质量特征评价;后一部分为土地的社会经济质量特征评价,在这两...该文基于美国的土地评价与立地评估(land evaluation and site assessment,LESA)方法,对陕西省泾阳县耕地进行了定级研究。把整个定级过程分为两个部分,前一部分为土地的自然质量特征评价;后一部分为土地的社会经济质量特征评价,在这两部分的评价中,采用主成分分析法选择评价因子。采用特尔菲法确定各因子的权重。最后在这两部分评价的基础上,对这两部分评价指数加权求和,得到定级单元总指数,这两部分的权重确定采用耕地质量综合指数与标准粮产量相关分析的方法来确定。结果表明,泾阳县耕地质量较高,全县耕地分为5级,一级耕地占全县耕地面积的14.43%,二级、三级、四级和五级分别占耕地面积的26.23%、26.07%、19.39%和13.88%。该文认为,LESA方法是土地定级的好方法之一。展开更多
Greenways are green landscape corridors which often apear along roads,mountain ridges,railroads,gas,water and power lines. They connect the fragmented landscapes and play a significant role in ecological protection .T...Greenways are green landscape corridors which often apear along roads,mountain ridges,railroads,gas,water and power lines. They connect the fragmented landscapes and play a significant role in ecological protection .Three distinct stages or "generation"can be identified in the emergence and evolution of greenways.展开更多
The Loess Plateau is a typical geographical unit with problems such as irrational land use, water loss and soil erosion, landscape fragmentation, and fragile ecological environment. Focusing on the green landscape con...The Loess Plateau is a typical geographical unit with problems such as irrational land use, water loss and soil erosion, landscape fragmentation, and fragile ecological environment. Focusing on the green landscape construction, the local people should practice intensive farming, protect aggregated farm patches, increase green corridors and scatter natural patches in order to compensate and recover ecological function of the landscape.展开更多
文摘该文基于美国的土地评价与立地评估(land evaluation and site assessment,LESA)方法,对陕西省泾阳县耕地进行了定级研究。把整个定级过程分为两个部分,前一部分为土地的自然质量特征评价;后一部分为土地的社会经济质量特征评价,在这两部分的评价中,采用主成分分析法选择评价因子。采用特尔菲法确定各因子的权重。最后在这两部分评价的基础上,对这两部分评价指数加权求和,得到定级单元总指数,这两部分的权重确定采用耕地质量综合指数与标准粮产量相关分析的方法来确定。结果表明,泾阳县耕地质量较高,全县耕地分为5级,一级耕地占全县耕地面积的14.43%,二级、三级、四级和五级分别占耕地面积的26.23%、26.07%、19.39%和13.88%。该文认为,LESA方法是土地定级的好方法之一。
文摘Greenways are green landscape corridors which often apear along roads,mountain ridges,railroads,gas,water and power lines. They connect the fragmented landscapes and play a significant role in ecological protection .Three distinct stages or "generation"can be identified in the emergence and evolution of greenways.
文摘The Loess Plateau is a typical geographical unit with problems such as irrational land use, water loss and soil erosion, landscape fragmentation, and fragile ecological environment. Focusing on the green landscape construction, the local people should practice intensive farming, protect aggregated farm patches, increase green corridors and scatter natural patches in order to compensate and recover ecological function of the landscape.
