细砂含量 meaning in English

fine concentration

4 . in the process of spontaneous vegetation recovery of blown sand soil , coarse sands ( l - 0 . 25mm ) content gradually lower , middle sands ( 0 . 25 - 0 . 05mm ) and fine sands ( 0 . 05 - 0 . 02mm ) , silt , clay content gradually higher in mechanical composition
4 、在自然植被恢复过程中，风沙土机械组成中砂粒含量变化表现为粗砂含量的降低，中砂和细砂含量的升高，砂粒整体含量降低。
Grain - size accumulation percentage of the aeolian sands in the past 150 ka in milanggouwan section is mainly characterized by the aeolian palaeo - mobile dune sands , which are composed of majority fine sands and minority very fine sands . there is n ' t almost any silt and clay . those of the fluvial facies , especially the lacustrine facies and palaeosols , are mainly composed of very fine sands and also contain some quantities of silt and clay
米浪沟湾剖面150kabp以来风成砂的粒度累积百分含量以古流动砂丘砂物质为主，其中以细砂含量最高，极细砂为次，几乎不含粉砂与粘土；河流相、特别是湖沼相与古土壤以极细砂含量占优势，且具一定含量的粉砂和粘土。