由这些颗粒物质组成的地层很常见，通常位于土壤下方看不见的位置。
Beds of this material, out of sight beneath the soil, are common.
空气不能穿透土壤颗粒，这使得土壤中缺少氧气。
Air cannot penetrate between the soil particles, making the soil oxygen-poor.
降水往往会把细小的粘土颗粒转移到土壤的最微小的空隙中，使这些空隙变得封闭，从而形成了一种几乎不允许任何水分渗透下来的表层土壤。
The impact of raindrops on the loose soil tends to transfer fine clay particles into the tiniest soil spaces, sealing them and producing a surface that allows very little water penetration.
应用推荐