Scale and biometric basis of soil bioindication for apple seedlings

The studies were carried out in 2010–2022 in the Lipetsk and Tambov regions. Soil (humus horizon) was sampled from apple orchards of different ages, soil types and subtypes. For the growing season, apple seedlings of the Renet Kichunov variety from open pollination were used. With an increase in the content of physical clay in the soil from 10 to 45%, the length of seedling shoots increased from 3.5 to 15.5 cm, the total dry biomass – from 0.7 to 2.2, including leaves – from 0.3 to 1 ,0, shoots – from 0.2 to 0.6, roots – from 0.2 to 0.6 g/vessel. If the content of physical clay reaches 85%, this leads to a stop in shoot growth and a decrease in the total dry biomass. With an increase in the leached chernozem bonitet from 75 to 90 points, the height of seedlings increases from 4 to 15 cm, the total dry biomass – from 0.3 to 1.9, including leaves – from 0.1 to 0.5, shoots – from 0 .1 to 0.4, roots – from 0.1 to 1.0 g/vessel. When the age of an apple orchard changes from 1 year to 20 years, the height of apple seedlings planted on this soil decreases from 40 to 4 cm, the total dry biomass – from 6.2 to 0.6, including the mass of leaves – from 3 to 0, 3, shoots – from 1.8 to 0.2, roots – from 1.4 to 0.1 g/vessel. This allowed us to develop a biometric scale by which we can estimate the age of the soil (degree of soil fatigue) using seedlings. The obtained data make it possible to propose biometric scales for assessing changes in the granulometric composition, quality of the soil and the time it remains in the apple orchard based on the biomass of apple tree seedlings of the Renet Kichunov variety.