连续种植作物后对土壤中各稀土元素消耗的研究

Depletion of Rare-Earth Elements in Soil after Planting Several Years

研究了在不施稀土的情况下 ,种植作物10年后对不同土层内各稀土元素B1、B 2 态及总量的消耗情况。结果表明 ,连续种植作物后 ,在作物根系密度较大的20～60cm土层内 ,相对于下层的土体 (80～100cm)来讲 ,各稀土元素B1 态的含量均大幅度降低 ;B 2 态随土壤深度的增加而增加 ,与土壤中活性Fe、Mn的含量呈显著的正相关 ;各层次之间稀土总量的差异不大。研究还表明 ,生物有效性较高的B1 态稀土元素的含量仅占稀土总量的1.83 %左右 ,比例很小 ;各稀土元素B 2 态的量是B 1 态的3～5倍。稀土总量变化的结果表明 ,植物地上部带走土壤中的稀土元素是非常有限的。

In this paper, depletion of rare-earth elements in soil at different depth has been studied after planting ten years without fertilizing rare-earth elements. It was showed that Ce, La, Nd and Yb of B 1 speciation decreased dramatically in the soil at 20～60cm depth after planting for ten years, compared to these elements in the soil at depth of 80～100 cm. Ce, La, Nd and Yb of B 2 speciation increased with soil depth and were significantly correlated with the concentration of availability Fe, Mn in the soil. B1 speciation was only 1.83% in gross rare-earth elements, which was efficient bioavailability. There was no obvious change of gross rare-earth elements among soil depth. There was no correlation between gross of rare-earth elements and plant absorbed, either. All these results suggested that the contents of absorbed REEs by plant were negligible. Fertilizing REEs as micro-elements fertilizer into soil should be very