Magnesium in Saline Gypsum-Bearing Soils of Russia

Abstract

Abstract Statistical analysis of 3802 samples of saline soils from different regions of Russia made it possible to substantiate preliminary conclusions about a higher proportion of magnesium in soils containing gypsum in comparison with gypsum-free saline soils. Gypsum is not a toxic salt and its presence does not cause an increase in salinity. Salinization is mainly related to sodium and magnesium salts, with the sodium percentage often exceeding the magnesium percentage. It is statistically substantiated that in the studied saline soils without gypsum, sodium often dominates among cations in the soil water extract (1 : 5) at any degree of salinity, The appearance of gypsum in the soil profile is accompanied by a significant increase in the proportion of magnesium. In slightly or moderately saline horizons with more than 1% of gypsum, the proportion of magnesium in the water extract (1 : 5) often exceeds 50% of the sum of sodium and magnesium according to the median, arithmetic mean, upper quartile, and maximum values. Even in strongly and very strongly saline soil horizons containing gypsum, the proportion of magnesium is significant with the median of 43 and 31%, respectively, which is 5.8–6.7 times higher than the proportion of magnesium in gypsum-free horizons of the same degree of salinity.