Analysis of the properties of saline soils of the Ust-Orda Buryat district of the Irkutsk region

The objective of this study is to analyze the properties of saline soils in the Ust-Orda Buryat Okrug of the Irkutsk Region, one of the most agriculturally developed districts, using available analytical data. The dataset contains information on 122 soil profiles of varying hydromorphism, 109 of which are saline. Nonparametric statistics were used to analyze the soil profiles for the district as a whole, as well as for individual areas and soils of varying hydromorphism. Automorphic and semi-hydromorphic soils often exhibit a low degree of salinity and a magnesium-sodium sulfate soil type. Predominantly hydromorphic soils are more frequently and strongly saline, and their properties determine the overall saline soil profile in the district. According to the median, saline soils in the district are predominantly medium loamy, with a pH of 7.6–7.96, a carbonate content of 18%, and a gypsum content of 8%. According to the median, moderately saline soils of sodiummagnesium sulfate composition with gypsum predominate in the district as a whole. Sulfates predominate among the anions in the district, while magnesium and, less frequently, sodium are the cations. Chlorides are present in saline soils in many areas, accounting for 22% of the sample overall, but do not predominate in any area. Toxic alkalinity is present in 24% of the sample, with values typically below 1 cmol(eq)/kg, which is determined by the presence of magnesium bicarbonate in 75% of cases. In 25% of cases, this alkalinity is of sodic origin. In horizons where alkalinity is determined by soda, the composition is most often alkaline-chloride or chloride with toxic alkalinity.