Аннотация:The influence of the contact of chernozem, soddy–podzolic, and gray forest soil aggregates with water on their water stability has been studied. An increase in the contact time of soil aggregates with water leads to a gradual decrease in their water stability. Based on the verified salt solution effect on the water stability of soil aggregates, the water stability of the loss of aggregates in contact with water is not directly proportional to the disjoining pressure. When soil aggregates come into contact with water, fractal clusters of humus particles (F-clusters) are isolated from them. It is suggested that the F-clusters that the soil gel is based on control the physical basis of the water stability of the soil.