Granulometric composition and moisture capacity of the soil in old-age apple orchards of the Lipetsk region

Abstract

The research was carried out in 2018-2021 in the old fruit-bearing, but not yet uprooted apple orchards of the Lipetsk region. The lowest moisture capacity was determined by the method of gypsum casts, the granulometric composition was determined by the pyrophosphate method. In old age (40-98 years) in apple orchards on chernozems leached in a layer of 10-40 cm of trunk strips, the granulometric composition changes: the proportion of physical sand increases, but the percentage of physical clay decreases. An increase in the proportion of physical sand in the trunk strips occurs mainly due to an increase in the proportion of fine sand (0.05-0.25 mm), and in the aisles an increase in the amount of physical clay occurs due to an increase in the proportion of medium dust (0.001-0.05 mm). With the age of the garden, the decrease in the proportion of physical clay in the trunk strips occurs due to the removal of medium dust (0.001-0.05 mm) and coarse silt (less than 0.001 mm) down the profile. The lowest moisture capacity increases with an increase in the proportion of coarse silt in the soil (r = 0.5), but decreases with an increase in the percentage of medium (r=-0.65) and coarse (r=-0.53) sand. A decrease in the percentage of physical clay in the trunk strips leads to a decrease in the lowest moisture capacity in a layer of 10-40 cm only by the age of the garden of 98 years. The change of the granulometric composition to a lighter one and the reduction of the lowest moisture capacity of the soil in the trunk strips of old apple orchards are evidence of the podzol–forming activity of apple roots.