PHYTO-RECLAMATION TECHNOLOGICAL METHODS OF BIOLOGICAL RECLAMATION OF DEGRADED PASTURES OF THE NORTHERN CASPIAN REGION

Purpose: to develop the main elements of the technology for creating a highly productive monocomponent agrophytocenosis from wheatgrass for pasture use on heavily degraded arid pastures of the Northern Caspian region. Materials and methods. A long-term experiment (2016–2020) on creating a monocomponent pasture agrophytocenosis was developed in the Astrakhan region under arid climate conditions on light chestnut soils. The experiment included options for sowing terms (autumn, spring) and seeding method: widespread and wide-row with sowing direction north – south and west – east. Control: natural pasture. The experiment was carried out according to the V. R. Williams All-Russian Institute of Plant Protection methodology, the mathematical processing – according to the “Methodology of Field Experiment” by B. A. Dospekhov. Results. The following was revealed: the stand of the vegetation cover of agrophytocenoses for the entire period exceeded the control by an average of 42 %; in the variant of the widespread method, the difference with the control was maximum and amounted to an average of 33 cm; the yield in the variants exceeded the control on average in the first year by 1.7 and by the fifth year by 6 times; the maximum excess of the control was noted in the variants of the widespread seeding method – 84.5 % and wide-row, west-east direction of sowing – 82 %; the yield of autumn sowing from the second year of vegetation exceeded the yield of the spring period by 22 %, and by the fifth year – by 8 %; in all variants, the total projective cover (TPC) exceeded the control by an average of 45 %; the maximum content of all nutrients in 1 kg of fodder was noted in the widespread seeding method, the wide-row method with the west – east direction was inferior to the leader by only 1–3 %. Conclusions. During the reclamation of degraded pastures on light chestnut soils in arid climate conditions, the best results in terms of grass height, yield and nutrient value were shown by such phytoreclamation techniques as sowing wheatgrass on black fallow in the autumn period (September) in a widespread or wide-row manner with a west-east direction.