The formation of herbage cover in forty-year-old plantation of black locust on the reclaimed dump in the Western Donbass

Abstract

The purpose of this paper is to study the formation of herbage cover in forty-year-old plantation of black locust (Robinia pseudoacacia L.), which has been growing under various forest growth conditions of artificial edaphotopes, which differed in stratigraphy and dumping depth on the reclaimed dump in the Western Donbass. The dump consisted of «empty» carefully planned mine rock; on its surface one-, two- and three-tiered structures of reclaimed land have been artificially formed. The maximum number of species in grass canopy of the black locust plantations has been recorded on technosol with typical chernozem. The formation of the grass canopy in plantations growing on technosol, consisted only of mine rock, the number of species depended on the power of edaphotope: with a decrease in dumping, a decrease in plant species has been observed. All studied variants are dominated by perennials. Under more favorable soil conditions, (variants 1 and 2) plants without vegetative movement dominate. With a decrease in the depth of dumping, the percentage of plants with slight vegetative movement increases. The representatives of plants with vegetative movement can be found under all forest growth conditions created on reclaimed lands. A specific trait of lithosol (variants 2, 3, 4) is an increase in mesoxerophytes, xerophytes and oligamegatrophs with a decrease in the power of dumping. Heliophytes predominate on studied variants with chernozem and loam with a dumping of one meter. Species partially demanding light have a significant advantage with the decrease in the power of dumping on lithosol variants with depth less than 0.6–0.3 meters. Among the coenomorphs, the dominance of ruderal and steppe complexes have been revealed. In the first case it is explained by the influence of anthropogenic factors (fire), –followed by the first stage of the restoration, namely colonization by weed plants; in the second case, it is caused by the influence of surrounding phytocenosis of undisturbed land and presence of herbal plants seeds from fertile soil level in pedosoil, which set the direction of succession towards the formation of zonal communities. Meadow and psammophytic coenotypes involved in the formation of flora indicate different types of forest growth conditions created by artificial soils.