ABSTRACT.
Assessment of peculiarities of weed formation in oilseed radish agrophytocoenosis using different technological models

Yaroslav Tsytsiura1*
 
There is limited information about the critical period for weed control (CPWC) in oilseed radish (Raphanus sativus L. var. oleiformis Pers.) This significantly limits the effectiveness of the applied technologies in its cultivation. The article focuses on the results of a long-term study (2013 to 2018) of the peculiarities of weed formation in oilseed radish agrophytocoenosis using different sowing technological models according to seeding rate and row spacing parameters. The study included the peculiarities of the species and generic composition of weeds and the basic attributes of the formation of species-specific amounts. The summed dominance ratio (SDR) was heterogeneous and co-oscillatory in the weed structure for both the formation of the number of individual species and their height dominance, which depended on the phenological stage of growth and crop development. In the general spectrum, the prevailing weed forms were identified with the highest potential for oilseed radish plants with an SDR greater than 1.0, which belong to groups I and VI according to environmental plasticity and stability, given the different conditions of the study period for both hydrothermal conditions and year index. In conclusion, a critical period for weed control (CPWC) in oilseed radish agrocoenosis was defined as a 5% reduction in crops ranging from 5 to 45 d after sprouting (DAS) for row sowing and a seeding rate of 4.0 million similar seeds ha-1 and 6 to 60 DAS for a variant of wide row sowing at a seeding rate of 0.5 million similar seeds ha-1.
Keywords: Critical weed control period, oilseed radish, oilseed radish-weed competition, weed control, weeds.
1Vinnytsia National Agrarian University, Faculty of Agronomy and Forestry, 21008, Sunny Street 3, Vinnytsia, Ukraine.*Corresponding author (yaroslavtsytsyura@ukr.net).