The influence of fertilizer systems on plant residues mass of agrophytocoenoses of short-term crop rotation, the balance of soil humus and ecologization of agriculture

Abstract

Three-year (2020–2022) studies on the black soil of a typical experimental field of the Bila Tserkva National Agrarian University found that on unfertilized variants fertilized with 6t/ha of manure + N64P54K58, 6t/ha of manure + N98P66K92 and 6 t/ha of manure + N126P82K116 according to the use of non-commercial products of agrophytocenoses as organic fertilizer, the dry matter of root residues was 2.64, respectively; 3.89; 4.64 and 5.13 tons, plant residues – 3.63; 5.25; 6.24 and 6.84 tons, and crop rotation productivity – 1.98; 3.42; 4.40 and 4.83 tons of dry matter of the main products and 4.48; 7.84; 10.22 and 11.43 tons of the main products and by-products of crops per hectare of arable land. With an increase in fertilizer application rates, the increase in marketable products of agrophytocenoses is higher than that of plant residues. At the same time, the ratio of the dry mass of the main products and byproducts of agricultural plants to the mass of their root and plant residues, as well as the share of their nonmarketable products, is increasing. A positive balance of soil humus was recorded only in the fields of white mustard and buckwheat, it is negative under the rest of the agrophytocenoses. On unfertilized plots fertilized with 6 tons of manure + N64P54K58, 6 tons of manure + N98P66K92 and 6 tons of manure + N126P82K116 with the use of by-products of agrophytocenoses as organic fertilizer, the balance of humus in the arable layer of typical black soil was positive and was, respectively, 0.34; 0.63; 0.55 and 0.60 t per hectare of crop rotation. When noncommodity crop production was removed from the fields, this indicator was negative in all experimental variants. In general, the share of humus formed from manure, plant residues, green manure and non-commodity crop products in the crop rotation was 0, 36, 31 and 33% on unfertilized plots, respectively; 10, 30, 27 and 33 % – fertilized with 6 t/ha of manure + N64P54K58; 8, 29, 27 and 36 % – fertilized with 6 t/ha of manure + N98P66K92; 7.29, 26 and 38 % – fertilized with 6 t/ha of manure + N126P82K116. According to the indicator of the ecologization coefficient of agriculture, the zero fertilization system (without the application of manure and mineral fertilizers) corresponds to biological farming, the first is ecological, the second and the third – the ecologization of the branch. Agrotechnically efficient is the use of agrophytocenoses by-products as organic fertiliser and ploughing only for a row crop in a five-field crop rotation. Key words: fertilization system, plant residues, humus, agrophytocenoses, crop rotation, ecologization , by-products (non-marketable products), productivity.