In order to study the effect of chemical amendments on fluorine migration in the paddy ecosystem of soda saline-alkali soil

pot experiments were conducted to study the changes of fluorine content in various forms of soil and the migration of soil fluorine to water and aboveground plants under the effects of aluminum sulfate

desulfurized gypsum and organic compound modifiers.The results showed that chemical amendments would affect the migration and bioavailability of fluorine in soda saline-alkali soil-water-crop system.After planting rice

the variation of soil water-soluble fluorine in each amendment treatment ranged from 8.33 to 20.90 mg/kg

which showed a downward trend compared with the control

of which aluminum sulfate treatment decreased the most

by 60.15%;Exchangeable fluorine and organic bound fluorine showed an increasing trend

among which the organic compound modifier treatment increased the most

by 79.54% and 86.37% respectively;The changes of iron manganese oxide bound fluorine before and after rice planting were complex

among which aluminum sulfate treatment had no significant change

the control treatment and organic compound modifier treatment increased by 19.05% and 42.03% respectively

while desulfurization gypsum treatment decreased by 22.79%;The contents of residual fluorine and total fluorine showed a downward trend

among which the residual fluorine decreased the most by 35.50% under the organic compound modifier treatment

the total fluorine decreased the least by 10.47% under the aluminum sulfate treatment

and the other treatments decreased by 12.50% to 12.55%.In the process of rice planting

the total cumulative released amount of fluorine from soil to water was control > organic compound modifier > desulfurization gypsum > aluminum sulfate.Compared with the control

the other three treatments decreased by 3.25%

5.13% and 5.19% respectively.The total migration amount of fluorine in soil migrating to rice stems

leaves and paddy was in the order of organic compound modifier > desulfurized gypsum > aluminum sulfate

the migration amount per unit soil was 0.44

0.40 and 0.25 mg/kg respectively

and the migration rates were 0.16%

0.15% and 0.09% respectively.The results of correlation analysis showed that the total amount of fluorine released from soil to water and transferred to rice stems and leaves in soil were positively correlated with soil pH

soluble salt and various forms of fluorine content

while the fluorine content of rice paddy was not affected by soil properties.Because the absorption of fluorine by rice stems and leaves under the aluminum sulfate treatment was significantly lower than that of other treatments

and the content of water-soluble fluorine in soil and the total amount of fluorine released from soil to water were also less

aluminum sulfate modifier had a better ability to reduce fluorine migration and bioavailability in soda saline-alkali paddy soil.