BIOCHEMICAL COMPOSITION OF DRY SUBSTANCE OF ABOVE-GROUND BIOMASS AND RAPE SEEDS

Abstract

The aim of the study was to analyze the biochemical composition of dry matter of aboveground biomass and seeds of Akkord spring rape to determine their value when used for feed. Rape was grown in 2016–2019 on sod-podzolic medium loamy soil of middle Urals with a humus content of 1.96 ... 2.25%, mobile phosphorus and potassium 166 ... 268 and 175 ... 273 mg/kg, respectively, рНKCl - 5.4 ... 5.7. The meteorological conditions of the growing season in 2016 were characterized as moderately arid and insufficiently wet (GTC - 0.51 ... 0.73), 2017 - moderately warm and humid (GTK - 1.94 ... 2.36), 2018 - optimal moist (GTK - 1.10 ... 1.70). We analyzed samples of dry matter of the aboveground biomass harvested during the budding period – beginning of flowering, as well as seeds in the phase of full ripeness. The concentration of most of the 70 evaluated chemical elements in seeds, with the exception of magnesium, phosphorus, sulfur, manganese, nickel, copper, zinc, bromine, was lower than in the aboveground biomass. Of the regulated elements (Hg, Cd, Pb, As, Cu, Xn, Fe, Sb, Se, Ni, Cr, Mo, Co) in the dry matter of green mass and seeds used for animal feed, the minimum permissible concentration did not exceed the established norms for all elements. The content of crude protein (22.8%), feed units (1.36 per 1 kg), metabolizable energy (13.0 MJ/kg) in rape seeds exceeded the values of these indicators in the dry matter of aboveground biomass –11.2%; 0.75 feed units and 9.6 MJ, respectively. The amino acid content also tended to increase in the seeds compared to the dry matter content of green mass: the total content of 13 amino acids was 14.14% and 6.40%. The removal of nitrogen from 1 ton of dry matter of aboveground biomass and rapeseed was, respectively, 30.9 and 58.2 kg, phosphorus - 6.5 and 25.5 kg, potassium - 22.0 and 40.5 kg