Influence of biochemical composition of above-ground biomass of oilseed radish on the expediency of its green manure application

Abstract

Over a ten-year period, the volumes of formed ground biomass of oil radish and its biochemical composition were estimated for spring and summer plantings in terms of its green manure application. The formed leaf and stem mass of the oil radish variety Zhuravka was studied using official AOAC international analysis methods, liquid chromatography, methods of field evaluation of yield and weight and equivalent indicators. The effectiveness of green manure application was assessed by the method of multicriteria-decision support. Oil radish was confirmed to have a high adaptive potential at the maximum level of determination of bioproductivity, with an optimal moisture and temperature supply of up to 40%. The long-term average productive and biochemical portfolio of oil radish was identified as follows: 21.19 t/ha of leaf-stem ground mass with 62.3% soil cover 70 days after sowing, 2.8% nitrogen, 22.8% fibre, 0.6% phosphorus, 3.8% potassium, 16.6 μmol/g glucosinolates at the C/N ratio of 14.7, 83% plant-mass quality, and 48.1 mol/ha biofumigation potential based on glucosinolate aucumulation. The study confirmed the high potential of oilseed-radish adaptability to the regimes of unstable moisture of territories, finding interannual variation of the total bioproductivity and biochemical parameters of leaf-mass quality with the value of the variation coefficient ranging 23.6–31.2%, depending on the sowing date. The effectiveness of oilseed radish was also revealed by comparison with the similar interannual variation of hydrothermal conditions of vegetation (the amount of precipitation 48.2%, average daily temperature 27.5%, moisture coefficient 68.1%, and aridity index 58.9%). Oilseed radish was found to be agrobiologically and agrotechnologically feasibile to be used in the system of both spring and summer (intermediate) green manure technologies in grey loess soils under conditions of unstable moisture, as indicated by its bioproductivity and biochemical quality of leaf mass, as well as the results of the components of the multicriteria assessment of the plant as green manure, the value of normalised weight coefficients ranging 0.62–0.99