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。
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.
在许多国家里,生产性表土的流失已导致日益严重的粮食短缺。
In many countries the loss of productive topsoil has contributed to growing food deficits.
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