Seasonal variations of the composition of soil solutions and of the properties of surficial soil particles in a plowed gray forest soil

The results of three years of station observations have shown that the seasonal variations of HCO₃^-, Cl^-, Mg²⁺, and Na⁺ in solutions from a gray forest soil under agricultural use are statistically insignificant, even when account is taken of the spatial inhomogeneity of the plots. The content of exchangeable Ca²⁺ and of nondissolving water and the specific soil surface vary cyclically in the course of the year; they are minimal in the winter and reach a maximum in the summer-autumn period. The reason for such variations appears to be the effect and residual effect of negative temperatures on the soil. -from Journal summary