氯酸盐是生产工业漂白剂二氧化氯的重要原料,也常被用作除草剂和土壤消毒剂,龙眼园施用氯酸钾不仅对土壤生态系统产生影响,施用不当还会造成植物损害乃至死亡.为了进一步明确氯酸根(ClO-3)在土壤中的迁移转化途径,在实验室条件下研究了氯酸盐在不同类型龙眼园土壤中的降解和吸附特性,探讨了可能对吸附造成影响的各种因素.结果表明,土壤对氯酸根有较弱的吸附能力,土壤中的微生物可以降解氯酸根,不同类型的土壤对氯酸根的吸附有显著性的差异,土壤对氯酸根的吸附符合Langmuir吸附等温方程.可参照不同土壤性质了解其降解和吸附氯酸盐的特性,确定龙眼催花的适宜施药剂量和采取相应土壤管理技术措施加快其降解,以减少氯酸盐的负作用.
Chlorates are a group of oxidizers with strong toxicity. Chlorate (CIO3) is used as a pulp-bleaching agent, in the manufacture of chlorine dioxide, as herbicide and soil sterilant. In recent years, off-season inducing flowering and fruit production all year round was realized by using potassium chlorate in longan (Dimocarpus longan, Lout.) orchard. However, the application of potassium chlorate may lead to the accumulation of residual chlorate in soil and subsequently have adverse impact on soil ecosystem. The aim of this paper is to study the decomposition and adsorption characteristics of chlorate in three types of soils in longan orchard. The chlorate sorption was significantly dependent on soil microorganism, the iron and aluminum oxides and organic matter content of the soil. The results indicated that the three soils showed faintish adsorption capacity of chlorate and the chlorate contamination could be reduced by soil microorganism. After the soils were sterilized by autoclave, their ability to adsorb chlorate followed the order Zhanjiang soil〉Guangzhou soil〉Maoming soil, which was closely related to their content of iron oxides and aluminum oxides, while, when the soils were sterilized by formaldehyde, the organic matter and ratio of C/N in soil played a significant role in inhibiting chlorate adsorption. It was also found that the adsorption isotherm followed the Langmuir isotherm adsorption model very well. According to the specific qualities of soil and its adsorption characteristics of chlorate, suitable chlorate application dosage and integrated soil management method can be adopted for reducing chlorate pollution in longan orchard.