Discussion on connotation and survey strategy of the ground substrate

The ground substrate is a new concept in the natural resource management area, and there are also controversies on that's connotation and how to plan the national survey.We defined it as the sub-ground material and function carrier of the Earth's Critical Zone, and believed it's lower boundary as the bottom of the phreatic layer.The rock, Quaternary sediments in geological fields and rock-, gravel-, soil-, mud-ground substrates can be composed by the same materials with different name.The investigated results of rock and Quaternary sediments can be transferred into different kinds of ground substrate.The ground substrate survey should be conducted on the basis of regional geological survey, hydrogeology survey, geochemical survey of land quality, soil general survey of soil to achieve the data of compositions, spatial distribution, physical and chemical characteristics of ground substrate.Moreover, the datas of ground substrate between the surveyed zone and the lower boundary of the phreatic layer, and some other unanalyzed data should be added.Furthermore, the research related to the function how the ground substrate affects the upper forest, grass and wetland needs to be strengthened.We supposed that the ground substrate survey should be deployed according to the comprehensive natural resource factors regionalization system in three steps.The first batch should focus on the areas with ecological problems such as grassland degradation, forest attenuation, soil erosion, to locate the problems and provide suggestions for ecological protection and restoration.The second batch should concentrate on key classic area of each Ⅱ grade regionalization area, conduct limited and necessary ground substrate of the scale of 1:250, 000 to map the Ⅱ grade area.The third batch should conduct compiling the national and regional map after the second batch, to provide some basic data and documents for territorial spatial planning.