The role of oilseed radish root mass in assessing the efficiency of green manuring systems
Faculty of Agronomy, Horticulture and Plant Protection Vinnytsia National Agrarian University, Soniachna Street, 3, UA21008 Vinnytsia, Ukraine
*Correspondence: yaroslavtsytsyura@ukr.net
Abstract:
This study provides an integrated evaluation of oilseed radish root mass in the context of its use as a long-term green manure. Under conditions characterised by optimal hydrothermal regimes, the crop exhibited a pronounced capacity for root mass accumulation, reaching 13.28 t ha⁻¹ (2.71 t ha⁻¹ in dry matter (DM)) under spring sowing conditions and 8.03 t ha⁻¹ (1.76 t ha⁻¹ in dry matter) under summer sowing conditions. The corresponding mean root-system productivity coefficients were 1.86 and 2.49, respectively. Analysis of the biochemical composition of root residues, averaged across sowing periods, revealed relatively low nitrogen levels (1.45% DM) alongside elevated carbon content (40.29% DM). The residues were additionally characterised by elevated concentrations of crude fat (2.07% DM) and crude fibre (42.7% DM), as well as a notable presence of glucosinolates (17.79 μmoles g⁻¹ DM), with ash content averaging 6.26% DM. Statistical analysis indicated that the variability of these biochemical parameters was moderately associated with thermal conditions, with coefficients of determination ranging from 23% to 44% in relation to mean daily air temperature, whereas precipitation showed an inverse relationship (25–49%). Based on the calculated biochemical ratios, the root mass can be classified as a material with the maximum achievable fertilizer potential (kg ha-1 active ingredient) N34.7P11.6K89.8Ca11.7S16.6. At the same time, its relatively high carbon and fibre contents indicate a potentially slow mineralisation pattern. These results demonstrate that root biomass should be explicitly incorporated into assessments of green-manure efficiency, as its contribution extends beyond aboveground biomass and includes both nutrient inputs and longer-term carbon and biologically active compound inputs to the soil.
Key words:
biochemical composition, fertilisation, green manure, mineralisation, root system