When the net income of amble land use reduces every year, and after that, the degree of intensity and the planted area reduce too, even more abandonment of amble land take place.

• 摘要当农地利用的纯收益逐年降低，且其后出现农地利用集约度降低和相应农作物播种面积减少甚至农地的弃耕撂荒现象时，就出现了农地的边际化现象。