Agroecological aspects of giant miscanthus cultivation in conditions of drained organogenic soils of the Left-Bank Forest-Steppe

Abstract

Goal. To establish the influence of long-term cultivation of giant miscanthus on the patterns of development of soil processes, the dynamics of their properties, the ecological state of agrolandscapes, and the productivity of the plantation in the conditions of drained organic soils of the basins of small rivers of the Left-Bank Forest-Steppe. Methods. Laboratory — to determine the agrochemical and water-physical properties of the soil; field — to study the plantation of giant miscanthus, taking into account natural, reclamation, and agrotechnical factors; quantitative — to establish the weediness of the plantation; mathematical-statistical — to determine the economic efficiency of growing giant miscanthus. Results. The study was conducted in 2015–2023 on a deep peat bog (1.8–2.0 m) drained old-horned carbonate in the floodplain of the river Supii at the Panfyly experimental station of the NSC “Institute of Agriculture of NAAS.” It was established that for 10 years of plantation cultivation of giant miscanthus agroecological properties of organogenic soil had undergone certain changes: at a planting density of 25 thousand pieces/ha in the arable (0–30 cm) soil layer, the density increased from 0.34 g/cm3 to 0.45 g/cm3, at the same time its crevices decreased to 75.4%, the total moisture capacity — to 178%. In the variant, at a density of 10 thousand pieces/ha, the soil density was within the range of 0.37 g/cm3, the crevices was 80.6%, and the total moisture content was 190%. The main agrochemical parameters of the soil layer of 0–30 cm were characterized by a non-significant decrease in the content of gross reserves of total nitrogen (from 2.0–2.1% to 1.9–2.0%) and an increase in the phosphorus content by 0.2–0.5% over the years of plantation use. The content of gross forms of potassium in the soil did not change and was at the level of 0.1–0.2%. The method of long-term cultivation of giant miscanthus had little effect on soil acidity, which varied within the pH range. — 7,4–7,8. Conclusions. Ecological and economic expediency of growing giant miscanthus for energy purposes in conditions of drained peatlands was substantiated. It was established that in the version of the experiment with the planting scheme of 0.7–1.4 m (10 thousand pieces/ha) for the introduction of K60 (on average for 2019–2024) received a consistently high yield of green mass — 78.9 t/ha, dry biomass — 28.67 t/ha, or 487.4 GJ/ha of thermal energy. The agroecological state of the drained organogenic soil (arable layer — 0–30 cm) in the 10th year of cultivation of culture at the same place in terms of soil fertility was close to ecological balance. Based on an analysis of the phytosanitary condition of the giant miscanthus plantation, it was established that additional measures to protect plants from pests, diseases, and weeds were not taken, since the economic threshold of harm was not exceeded.