This is partly related to the fact that agricultural productivity is very low and, with rising populations, average farm sizes are getting smaller, thereby creating a situation where it is difficult to make a reasonable living from the land.
其中部分原因是，农业生产率十分低下，人均耕地面积随着人口的增长而缩小，造成了难以利用土地合理谋生的状况。