为什么现在的河流的水污浊？水质偏褐色呢？-实验图

我们都听过学者说没有植物生长的土壤经过雨水的冲刷，很容易造成土石流。上面由环境保育学家Roland Yawan 所做的小实验很清楚可以看到，左边有种植物的土壤所流出来多余的水是清澈的，而右边完全没有植物的土壤则被水带出很多泥沙。

A great experiment to illustrate soil erosion! This simple experiment shows the importance of trees as a part of our environment. The water that runs through soil with
vegetation (left corner), comes out clear, while the other two without vegetation is muddy.