求翻译：在腐殖质层变幅比较小，淀积层有一明显增大的趋势，这是由于腐殖质层受植物根系的影响，土质疏松多孔，土壤容重较小，淀积层土壤小石砾含量大，甚至有的林型出现白浆化，结构紧实，使土壤容重较大，也可能由于长期的重力、水文等的作用，土壤粒级分布和有机质含量、根系等共同作用的结果。是什么意思？

In humus layer variable site than smaller, Dian product layer has a obvious increases of trend, this is because humus layer by plant roots of effect, soil loose more hole, soil capacity heavy smaller, Dian product layer soil small gravel content large, even some forest types appears white pulp of, structure compaction, makes soil capacity heavy larger, also may because long-term of gravity, and hydrological, of role, soil grain level distribution and organic matter content, and roots, common role of results.