3-4 p49 5.6段翻譯

The B horizon(subsoil) and the C horizon (parent material) contain most of a soil's inorganic matter,mostly broken-down rock consisting of varying mixtures of sand,silt,clay,and gravel, much of it transported by water from the A horizon.The C horizon lies on a base of parent material ,which is often bedrock.The spaces,or pores,between the solid organic and inorganic particles in the upper and lower soil layers contain varying amounts of air(mostly nitrogen and oxygen gas) and water.Plant roots use the oxygen for cellular respiration.As long as the O and A horizons are anchored by vegetation,the soil layers as a whole act as a sponge, storing water and releasing it in a nourishing trickle.


B 地平線(下土層) 以及 C 地平線(母質層) 包含大多數土壤的無機物，大部分的岩石組成是由沙、泥沙、泥土、和碎石混合變質而成，而這些組成大部分都是被水從 A 地平線(表土層) 搬運過來的。C 地平線 位於一個母質層的基礎上，這經常是床岩。在上部和下部土壤層的固體有機和無機物粒子之間的空間或孔洞包含著不同量的空氣(氮和氧為主)和水。植物的根把氧用於細胞呼吸。只要 O 地平線 和 A 地平線 被植物固定，泥土層就可以當作是一塊海綿，儲存水分和釋放水分保持滋養。