The nutrients are deep down in the active layer anyway, not high up near the surface, which is the part of the active layer most affected by run-off.

不管怎样，营养物质存在于活性层深处而不是在表层附近，活性层受径流影响最大的地方。

youdao

One major problem is that degraded soils become compacted and so absorb less water, which then tends to run off the surface, taking topsoil with it.

一个主要的问题是，退化的土壤变得密实，造成吸水量减少，从而导致水从地表流失并将表土带走。

youdao

As more droplets are attracted, they spread out and eventually join together and run off the surface-as they do on a pane of glass.

越来越多的水滴聚集，滚到涂层上，就像在玻璃板上一样。

youdao

One is an immediate effect as surface run-off takes roughly 50% of the free nitrate straight into Thames tributaries and the main river.

BBC: Thames archive reveals long nitrate rise

Building what could be "an awful lot" of new properties in Feniton would, she said, add to the surface run-off into drains that were already struggling to cope.

BBC: Feniton flooding, November 2008