For controlling source pollution from the sources, sloping land management in the headwater regions is necessary.

为了从源头上控制农业面源污染,必须根据土壤生物热力学原理,以土壤为中心, 大力治理坡地.

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In arid climates, surface water is generally better than water in headwater areas, but poorer downstream.

在干旱气候的上游区, 地表水一般较地下水好, 但下游的地表较差.

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