造成中低产土壤的主要因素是土壤养分缺乏，其次是部分土壤存在障碍因素。

All above are composed of lower to medium fertile soils and lacking of nutrients is of main reason of low yields.

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结果表明，研究地区林地土壤养分普遍缺乏，其中以土壤有效养分的缺乏尤为严重。

The results showed that the levels of nutrients in the soils were very low, especially for the available nutrients in the soils.

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土壤养分（N）缺乏，酚积累，最终导致多酚氧化酶活性增强。

Nitrogen absence results in phenol accumulation which results in an increase in the activity of phenolase.

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土壤养分（N）缺乏，酚积累，最终导致多酚氧化酶活性增强。

Nitrogen absence results in phenol accumulation which results in an increase in the activity of phenolase.

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