不少老菜园经过多年种植后，土壤老化，产量下降，必须对土壤进行改良，才能获得高产。老菜园土壤老化的主要原因是：施肥不当，滥用化肥或单一使用氮肥，造成土壤酸化或碱化；有机质缺乏，土壤团粒结构被破坏，土壤板结，保肥能力或通透性下降；雨水淋溶，使土壤中代换盐基离 After many years of cultivation of old vegetable garden, soil aging, production decline, the soil must be improved in order to obtain high yield. The main reasons for the aging of old garden soil are: improper fertilization, excessive use of chemical fertilizers or nitrogen fertilizer, causing soil acidification or alkalization; lack of organic matter, soil aggregate structure is destroyed, soil compaction, fertility or permeability decreased; rain leaching , So that instead of salt in the soil from the base