leach

verb [vt. 及物动词]过滤，滤去；萃取；被过滤，沥滤

Once the humus layer disappears, nutrients cannot be recycled and leach from the soil, converting soil from fertile to infertile and making it suitable only for savanna vegetation.
一旦腐殖质层消失，养分就无法从土壤中回收和过滤，致使土壤由肥沃变为贫瘠，只适于热带草原植被的生长。