Scholarly record

LINEAR SOIL-ECOLOGICAL ZONES IN AGROFORESTRY LANDSCAPE OF THE CENTRAL RUSSIAN UPLAND FOREST-STEPPE

Yu. G. Chendev, Aleksandr Gennadiev, С. В. Лукин, Е. А. Заздравных, Maria Petina

Abstract

Soils of flat watersheds under shelterbelts and on adjacent arable lands on three areas with different climatic conditions were studied. The study area is a forest-steppe of the central part of the East European Plain (Belgorod oblast, Russia). In all areas chernozems with 60-80 cm dark-grey (reached by organic matter) part of profile (A1 + A1B), are developed. The parent materials are loess-like loams and clays. The width of all shelterbelts is 30 meters; they are oriented from south to north; the age of the shelterbelts is 50-65 years. The stand of shelterbelts is represented by species of typical natural forest-steppe forests: oak, ash, maple, elm. In the fields surrounding the shelterbelts, in conditions of rainfed agriculture, the traditional cultivation of row crops and grain crops is carried out. The detailed study of soils under shelterbelts and on arable lands at different distances from them showed that in the process of the shelterbelts functioning, linearly oriented zones - strips with a different set of soil properties were formed. Under central parts of the shelterbelts, zones with minimum soil bulk density, maximum pools of humus, as well as with a maximum loss of clay fraction in the 0-20 cm layer are formed. In these (axial) parts of the 50-65-year-old shelterbelts, the vitality of forest stands turned out to be weakened, which was reflected in the appearance of a significant number of dead trees - sources of soil’s Corg replenishment. The peripheral parts of the shelterbelts are characterized by the higher vitality of forest stands and the increased content of available phosphorus and potassium in soils. According to our hypothesis, this is due to the pumping of substances from the mineral fertilizers applied to the arable soils - by the root systems of trees, spreading from the edges of the shelterbelts towards the arable lands over a distance of more than 10 meters. The effect of root desuction in spring period is clearly expressed by the spread from shelterbelts in different directions to adjacent fields of areas with low reserves of soil moisture in the upper soil horizons. The third soil-ecological zone with the width of 20-30 meters is distributed on both sides of the shelterbelts on arable land. It is characterized by increased soil density as a result of regular passages of agricultural machinery - more frequent than in field areas farther from the shelterbelts. In these areas, in the arable horizons, there is an increased content of the clay fraction in comparison with farther areas of fields from the shelterbelts. The increased clay content may be due to the combined effect of plowing (associated with physical crushing of soil particles) and compact of these soils due to more frequent passages of machinery. At a distance from the shelterbelts of 30 meters or more, the variability of most soil indicators (pH, content and stocks of clay, humus, available phosphorus and potassium, etc.) does not have a definite trend, which indicates a weakening of the influence of shelterbelts on soil properties further than 30 meters from their edges. The identified soil-ecological zones and the differentiation of soil-forming processes occurring in them should be taken into account in the practice of agroforestry, as well as in the specifics of the use of new farming technologies management - landscape-adaptive, precise, and others.

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