蚯蚓深深地鉆進(jìn)底土.Earthworms burrow deep into the subsoil.進(jìn)入底土的化學(xué)物質(zhì)會減少，這對土質(zhì)松軟的熱帶土壤而言尤為重要。Less chemical gets into the sub-soil which is particularly important with the light, tropical soils.土壤中含有效鋅轉(zhuǎn)低時, 深層耕翻會使缺鋅的底土暴露出來.In a solid ...