Fluorine and Iodine in Soils of the Kulunda Plain

Abstract

The content and distribution of fluorine (F) and iodine (I) have been studied using the example of a four soils located on the terrace of Kuchukskoye Lake in the Altai kray. Soil sections are located on various elements of the micro relief within the boundaries of the lake terrace. The textural-carbonate stratified chernozem (Calcic Chernozem (Loamic, Areninovic, Bathyraptic)) occupies the top of the micro relief. The Solonchak quasi-gleyed (Calcic Solonchak (Loamic, Sulphatic, Humic) is located in a micro-depression. The absolute difference in elevation between these soils is 1 m. Solonetz dark quasi-gleyed salted (Protosalic Solonetz (Loamic, Humic) and texture-carbonate quasi-gleyed salted (Calcic Gleyic Chernozem (Loamic, Endosalic) are confined to the slope between the Calcic Chernozem and Solonchak. The total content of halogens and their mobile forms were determined: water-soluble for F and salt-soluble for I. The content of total F in soils averaged 277.40 mg/kg (lim 59.83–541.10 mg/kg), water-soluble – 3.47 mg/kg (lim 0.04–16.45 mg/kg). Statistical calculations proved that the content of total F strongly correlates with the content of clay, carbonates and water-soluble sodium-cation, and the value of the correlation coefficient depends on the type of soil and its position on the micro relief. Water-soluble F has a high positive correlation with similar parameters in the Chernozem and in the Solonetz. The results showed that the content of total I in the studied soils is higher than in zonal soils of this territory, averages 13.61 mg/kg of soil (5.27–15.21 mg/kg) and moderately depends on the content of clay and carbonates. The influence of the soil type and its position on the micro relief was not revealed on the content of total I. The average content of salt-soluble I is 0.71 mg/kg (0.01–1.86 mg/kg). For all studied soils except Solonchak the relationship of the content of salt-soluble I with the content of clay, carbonates and water-soluble sodium cation has been established. No significant correlation between the above-mentioned parameters has been established for the Solonchak. The revealed heterogeneity of the spatial distribution of F and I in in the studied soils should be taken into account when conducting regional assessments of the status of these halogens.