The influence of the properties of brown skeletal soil on the growth and development of persimmons

This study was done in order to study the degree of influence of soil properties on the growth and development of eastern persimmon trees (Diospyros kaki Thunb.) growing in the gene fund collection of the Nikita Botanical Gardens. The plants were planted according to the 5×5 m pattern. Soil sections were laid under the fruiting persimmon trees. Areas with groups of trees in a normal, satisfactory and depressed state were allocated for this study. The soil cover of the all area is represented by brown planted soils formed on mixed deluvial products of weathering of limestone, sandstone and shale. According to the depth of the dense underlying rocks, the soils are divided into thin (40-80 cm), medium-thick (80-120 cm) and thick (>120 cm). Under each group of trees, the soils are strongly skeletal, containing up to 28% of skeletal particles by volume. The volumetric mass of fine earth in the 0-60 cm layer ranged from 1.50 to 1.57 g cm^‑3. In the study area, the soils are rich in fine earth (6603-4569 t ha^‑1) and humus (154.0-248.4 t ha^‑1). They contain a low amount of CaCO₃ (0.70-0.96%) and they are not salted with readily soluble salts. The reaction of the soil solution is alkaline; pH is in the range of 8.03-8.28. The study of the persimmon plants reaction to the brown soils properties made it possible to determine that the limiting factors for successful cultivation of persimmons are the high density of fine earth and the depth of the parent rock. Moreover, the content of skeletal particles in brown soils in the range of 20-60% does not significantly affect the growth and productivity of persimmon trees. For the normal growth and development of persimmon trees, the stocks of fine-grained soil should be at least 15 thousand t ha^‑1, and the reserves of humus – 276 t ha^‑1. Brown soils with fine earth very not exceeding 1.55 g cm^‑3, a total porosity of not less than 42% and a root thickness layer of 120 cm or more are suitable for persimmon plantations.