SUCCESSIONAL TRANSFORMATION OF FALLOW RECLAIMED LANDS AGROPHYTOCENOSIS IN THE NORTH-WEST OF RUSSIA UNDER AGROTECHNOGENIC IMPACT CONDITIONS

Abstract

It was determined during the study that a technogenic succession of perennial gramineous motley grass phytocenosis took place on reclaimed agricultural lands near mining company. The goal of a study was to estimate the shift in botanical composition and productivity of perennial agrophytocenosis on reclaimed fallow soils under aerial technogenic influence in Karelia. Over the last three years perennial gramineous herbs (Bromopsis inermis L., Phleum pratense L.) and motley grass (Urtica dioica L., Anthriscus sylvestris L., Chamaenerion angustifolium L.) are dominant in phyto-association. As we move away from mining location (100, 200, 300 meters) a gradual natural shift in vegetation takes place. The quantity of gramineous herbs decreases (from 77,8 to 42,9%) and the quantity of motley grass increases (from 21,2 to 56,8%) as compared to a control plot (16,5 and 82,9% accordingly). Low level of rainfall at the first half of summer, which is normal for Karelian climate, presence of polluting substances in soil and on surface caused substantial decline in growth of valuable fodder such as Bromopsis inermis (linear indicator 20,7 – 31,8 centimeters) as compared to background conditions (40,2 centimeters). Also, the mentioned above circumstances caused increase of total yield of perennial grass (13,2 – 16,4 – 22,0 tons per hectare; background – 28,0 tons per hectare) as we move away from mining location.