底土层 meaning in English
chorizon
ground layer
substratum
Examples
- By reducing the permeability of soil at the bottom of pit and selecting optimal dewatering depth , the settlement of ground surface can be well controlled
采用降低坑底土层渗透性的措施和选择最佳的降水深度能有效地控制坑外地表的沉降。 - Meanwhile , most aspects about this perspective are concerned , which include quantification of the soil water background of the plateau area , the regional spatial variation of soil water background and variation along the slope , mosaic structure and seasonal changes etc . the results show that : ( 1 ) for the fundamental circumstance for vegetation development is the original debilitated slope , so the perspective of soil water background specially for the loess plateau refers to the soil water conditions on the original slope . ( 2 ) the value of soil water background appears to be a descending trend from south to north based on the difference of vegetation zones . in the forest zone , soil moisture contents beneath 3m depth from the soil surface are more than 12 % usually ; in the forest - pasture zone , the values of soil moisture content beneath 4m depth underground are more than 6 % and stable , and tend to be ascending while the depth increases ; but the values in the dry pasture zone is lingering between 4 % to 6 % from the surface layer to sub - layers
发展了“土壤水分背景”的概念，并以之为基础对其各个方面进行了研究，使之形成一个相对独立和完整的体系，主要包括黄土高原土壤水分的背景值、土壤水分背景的区域分异、坡面分异、镶嵌结构及其季节分异等： ( 1 )由于植被生长发展、演替的基础阶段是天然草被群落，故认为黄土高原的土壤水分背景在概念上是特指该区天然草被群落下的土壤水分状况； ( 2 )黄土高原的土壤水分背景值，根据植被地带的不同表现出自南向北逐渐降低的规律：森林地带3米以下土层水分背景值普遍稳定地高于12 ，森林草原地带4米以下土层水分背景值稳定大于6 ，且均随土层的加深水分含量逐渐增加，而草原带的土壤水分背景值自土表至底土层一直在4 6之间徘徊。