Abstract: The variation of F content in rice plants and in paddy soil at different Al2(SO4)3 application levels was investigated in a biological pot experiment. The results showed that rice plants absorbed F extravagantly, and the order of F content in each part was as follows: husk＞brown rice ＞root＞straw. At a given   F level in soil, the concentration of F in each part was firstly decreased and then increased with rising Al2(SO4)3 application level. It minimized at 0.4% and 0.6% of Al2(SO4)3  levels, showing extremely significant difference with the blank control. As Al2(SO4)3 application level increased, the contents of free F and water soluble F were gradually decreased. The linear analysis showed that the two forms of F was negatively correlated with the amount of Al2(SO4)3 . But there was significant positive correlation between the content of residual F and Al2(SO4)3. The content of exchangeable F in soil   firstly increased   and then decreased with the increase of Al2(SO4)3 application amount and peaked at 0.2% Al2(SO4)3  level.  However, the exchangeable F content in soil at 0.2% Al2(SO4)3 level  was not significantly different from that of the control, and was extremely significantly differed with those at 04%-0.8% Al2(SO4)3 levels, indicating that Al2(SO4)3 mainly depressed the exchangeable F. The contents of complex F, Fe/Mn binding F and organic F were also firstly increased and then decreased with their maximum appeared at 0.4% and 06% Al2(SO4)3  levels. Correlation analysis showed that there was a significantly or extremely significantly negative correlation between the concentration of F in each part and the contents of Fe/Mn binding F, organic F in soil. Thus, at 0.4%-0.6% Al2(SO4)3 levels, equivalent to the F∶Al quality ration of 6∶1- 4∶3, the F concentration in each plant part was relatively lower, which indicated that its defluoridation efficiency was better. At the same time, the contents  of water soluble F, exchangeable F were lower and the contents of Fe/Mn binding F, organic F were higher which reduced F infiltration to groundwater and lower the F intake by people and animals  eating cooked rice and drinking groundwater.

Key words: rice, Al2(SO4)3, F content, F form, F defluoridation

摘要： 通过盆栽试验研究了不同硫酸铝用量对水稻植株及稻田土中氟含量的影响。结果表明，水稻植株对氟存在着奢侈吸收的现象，各部位氟浓度的顺序为稻壳＞糙米＞根＞茎叶。在相同氟浓度下，随着硫酸铝用量的增加，水稻植株各部位的氟浓度呈先降低后增加的趋势，在0.4%、0.6%硫酸铝处理下出现最低值，并且与对照差异极显著。土壤中自由态氟和水溶态氟含量随着硫酸铝用量的增加而呈逐渐降低趋势。线性分析表明两种氟与硫酸铝用量呈极显著负相关；而残余态氟则与硫酸铝用量呈极显著的正相关；虽然土壤中可交换态氟含量随着硫酸铝用量的增加呈先增后降的趋势，并在0.2%硫酸铝处理下出现最大值，但是统计分析表明， 0%和0.2%硫酸铝处理间差异不显著，而在0.2%~0.8%硫酸铝处理间差异均达极显著水平。这说明铝对交换态氟的作用以抑制为主；络合态氟、铁锰结合态氟及有机态氟的含量也呈先增加后降低的趋势，最高值出现在0.4%、0.6%硫酸铝处理。相关分析表明，植株各部位的氟浓度与土壤中铁锰结合态氟和有机束缚态氟含量呈显著或极显著负相关。因此，当硫酸铝用量为0.4%~0.6%时（相当于氟铝的质量比为6∶1~4∶3），植株各部位的氟浓度较低，降氟效果较好；而且此时土壤中水溶态和交换态氟含量相对较低，铁锰结合态和有机束缚态氟含量相对较高，能够减少氟向地下水的渗透，从而降低人畜通过地下水和米饭所摄入的氟量。

关键词: 水稻, 硫酸铝, 氟含量, 氟形态, 降氟