The study on soil heavy metal content of apple orchard in gully region of the loess plateau showed that high input and different apple tree ages have an obviously effect on soil heavy metal content and its migration.The soil Cu content increases along with the tree age increases.The input and output of soil Cu tends to be balance when the apple tree have planted more than 20 years,and the Cu content change is very small,and the topsoil Cu content is higher than the other soil layers.The soil Cr content incr...
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