水溶性有机质对茶园土壤氟形态的影响

采用元素分析与傅里叶变换红外光谱相结合的方法分析了腐熟鸡粪中水溶性有机质(dissolved organicmatter,DOM)的结构及组成,通过溶液连续提取-电位分析法分析茶园土壤中氟的形态及含量。结果表明,腐熟鸡粪DOM中C、O、H和N元素含量占元素总量的93%,其中C和O的含量大于H和N,C/H和C/N较大,C、H饱和度低,含有较多羧基、醛基、酮基等不饱和度高的物质。水溶态和有效态氟含量随外源DOM添加量的增加而降低,呈负相关关系;而土壤铁锰结合态氟、有机结合态氟含量则随外源DOM添加量的增加而升高,呈正相关关系。外源DOM的加入可降低茶园土壤水溶态和有效态氟含量,提高了铁锰结合态氟、有机结合态氟含量,降低氟的生物可利用性。

Influences of dissolved organic matter on fluoride fractions in soils

The structure and composition of dissolved organic matter(DOM) extracted from the composted chicken manure were analyzed using elemental composition analysis and Fourier transform infrared spectroscopy(FTIR) methods,and the impacts of this DOM on the fractions of fluoride in soil were analyzed by using sequen-tial extraction procedure and potentiometric analysis methods.The contents of carbon and oxygen were higher than that of hydrogen and nitrogen,accounting for 93% of all the elements in the DOM extracted from composted chicken manure,respectively.Moreover,the carbon and hydrogen saturation was low because of high contents of carboxyl,aldehyde and ketone functional groups in the structure of DOM.As 50%,100% and 200% of DOM added into soil,the contents of water soluble fluoride and available fluoride were declined,and the negative rela-tionship was observed with the increasing dose of exotic DOM amendments in soil.While the concentration of Fe/Mn bound fluoride,organic matter bound fluoride were increased as the same dose of DOM introduced into soil,and the positive relationship was found for the Fe/Mn bound fluoride,organic matter bound fluoride.The exotic DOM may decrease the water soluble and available fractions of fluoride,and increase Fe and Mn bound fluoride,organic matter bound fluoride in tea plantation soil.