外源稀土在土壤中各形态的动态变化

在小麦整个生长期内定期测定外源稀土进入土壤后各形态稀土随时间的变化,结果为:外源稀土进入土壤后可交换态稀土含量随时间的延长显著降低,减少的可交换态稀土一部分被小麦吸收,一部分被土壤所吸附,其中在分蘖期减少得最快;根系的分泌活动明显影响土壤中稀土元素的存在形态,铁锰氧化物结合态稀土含量在拔节期前逐渐增加,拔节期后略有下降;碳酸盐结合态稀土含量随时间的延长而降低,但下降幅度较小;有机物结合态与残渣态稀土含量随时间的延长没有发现明显的变化.

Species Dynamic Change of Added Rare Earth Element in Soil

After Rare Earth elements (REEs) was applied into soil, content of exchangeable species decreased obviously with time lapsing. The fastest decrease of content of exchangeable species occurred at wheat tillering stage. A part of the lost content of exchangeable species was absorbed by wheat, and the other part of that was absorbed by soil. The surface activity of iron/manganese oxide was influenced obviously by the secretion function of root, content of iron/manganese oxide binding species rapidly increased before wheat jointing stage, but it decreased quickly after wheat jointing stage. At all time, content of carbonate binding species decreased with time lapsing, and content of residual species and content of organic binding species didn't change.