Wind resistance of southern carbonate and ordinary сhernozems in agroforest landscapes of the steppe zone of Russia

Abstract

Relevance. The rate of destruction of chernozems in the steppe zone as a result of deflation is very high. There is a threat of their loss of the humus horizon. To optimize the complex of protective measures, it is necessary to establish the regularities of the formation of wind resistance of these soils.Methods. The seasonal dynamics of the structure of the upper layer (0–5 cm) of chernozems of the steppe zone of the Lower Volga region and the Central Pre-Caucasus in the network of forest belts is studied. The aggregate composition was determined by fractionation of an air dry sample. The wind resistance of the soil was assessed by the total content of particles with a diameter of less than 1 mm.Results. It has been established that the open surface of southern carbonate chernozems is deflationary dangerous at any time of the year. Two spraying peaks were revealed — in early spring and before harvesting grain crops. In the first period, the content of particles with a diameter of less than 1 mm was 33–47%, in the second — 60–61%. Shelter forest belts reduced soil spraying in the zone of effective influence. A change in the internal structure of the deflationally dangerous fraction was detected during the year. The disintegration of large aggregates and an increase in the volume of smaller ones were observed. By the harvesting period, the number of particles with a diameter of 0.5–1.0 mm decreased by 1.7–2.6 times compared to the spring. Number of aggregates with a diameter of 0.1–0.5 mm, most strongly blown by the wind, increased by 1.3–1.8 times. The total dispersion of ordinary chernozem is almost two times lower than that of southern chernozem. However, the amount of particles with a diameter of 0.1–0.5 mm in the deflationary dangerous fraction of southern carbonate chernozem in the spring period is 37%, during the harvesting period — 50–56%. And in ordinary chernozem, already since the spring, there are more than 55% of such particles, in the future their number increases to 60%. As a result, by the harvesting period, the danger of a fraction with a diameter of less than 1 mm becomes the same for both subtypes of chernozems. This requires adjusting the complex of protective measures.