Изменения физических свойств черноземов сегрегационных в агролесоландшафтах Центрального Черноземья

Abstract

The basic physical properties of chernozems in agroforest landscapes of the Central Chernozem region are studied within the framework of the program by the topic of the state assignment for 2018–2020. The studies carried out in the conditions of agrocenoses and undisturbed ecosystems were divided by the effect of agrogenic and agroforestal nature. Agrogenic effect was considered through a case study of the fallow lands put in operation in tillage. While agroforestal effect was considered through a case study of the influence of forest belts on soil cover. It is found that rearrangement of soil aggregates number takes place under the influence of forest belts and at introduction of fallow lands to agricultural use, but in different scenarios. The soil blocky fraction (less than 10 mm) in the arable horizon increases by 6–14 times under the agrogenic effect in comparison with the fallow. Contrary to this, the share of silt fraction (less than 0.25 mm) on the arable land decreases by 2–4 times and the structure coefficient decreases by 8–13 times. The minimum content of agronomically valuable aggregates (sum of 0.25–10 mm) is registered for the arable land soils compared to the fellow and forest belt for all selected layers. The average amount of aggregates lies in the range of 58–73 % for the arable lands, whereas the share of aggregates in the size of 0.25–10 mm is in the range of 85–95 % for the forest belt and fallow. A content reduction in the fractions of the following sizes 0.25–0.5; 0.5–1; 1–2; 2–3 and 3–5 mm influenced on a decrease in the agronomically valuable structure of the arable land in comparison with the fallow. The agroforestal effect on the structural composition of soil cover is more gently. The share of soil blocky fraction increases slightly. The sum of the agronomically valuable aggregates in the soil of the forest belt in depth of 10–20 and 20–40 cm corresponds the chernozem level of the fallow. Herewith, the share of the silt fraction in the soils of the natural cenoses is higher. And as a consequence of this, the values of the structural soil coefficient of the forest belt chernozem insignificantly exceed similar values in the fallow soils at the same depths. Statistical features of distribution of the basic aggregates in the soils subjected to intensive agrogenic and agroforestal influence are established in comparison with the fallow lands. Some statistical characteristics of distribution of the basic structural separates of the chernozem soils are calculated. The indicators of bulk density at various depths of the study sites are defined. They increase in the row of fallow – forest belt – arable land. For citation: Turusov V.I., Cheverdin Yu.I., Bespalov V.A., Titova T.V. Changes in the Physical Properties of Segregational Chernozems in Agroforest Landscapes of the Central Chernozem Region. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 4, pp. 95–112. DOI: 10.37482/0536-1036-2020-4-95-112