Ecological plasticity and stability of cabbage crop ptoductivity as affected by method of sowing

Purpose. To establish the peculiarities of the formation of ecological plasticity and productivity stability of winter cabbage crops as affected by the components of agricultural technology, specifically the width of the rows and the application rates of mineral fertilizers. 
Methods. The research was carried out in the years 2018–2021 in the Chernihiv region at the Nizhyn Agricultural Technical Institute of the National University of Life and Environmental Sciences of Ukraine). Conventional methods were used in the research. The field experiment design provided for the cultivation of typhoon variety ‘Orakam’ under different methods of sowing (width between rows of 15, 30 and 45 cm) and rates of mineral fertilizers (without fertilizers, N80P60K60 and N120P90K90). Parameters of ecological stability (b) and plasticity (W) of seed yield and energy yield from biomass were calculated according to the Eberhard-Russell method using the Mathcad Prime 3.1 software. 
Results. The lowest stability of both seed yield (0.55–0.79) and energy yield from biomass (0.55–0.81) was noted in the treatments without fertilizers, while with N80P60K60 and N120P90K90 it was almost twice as high (1.03–1.33 and 0.97–1.32, respectively). At the same time, within all three fertilization backgrounds, a clear tendency of decreasing crop productivity stability along with increasing row width was observed. In particular, the highest coefficient of stability of seed yield in the experiment (1.33) was obtained on the background of N80P60K60 at a row spacing of 15 cm, at the same time as the row spacing increased to 30 and 45 cm, it decreased to 1.19 and 1.05, respectively. As for the plasticity parameters of the productive indicators, they were approximately at the same level in all treatments. 
Conclusions. The best conditions for the formation of high seed yield and total energy yield from the biomass of typhoon variety ‘Orakam’ were provided at a row width of 15 and 30 cm and the application of mineral fertilizers N80P60K60 and N120P90K90. In this case, the formation of crop productivity demonstrated a high level of plasticity. In general, intensive cultivation conditions contributed to the full realization of the crop biological potential and effective utilization of fertilizers.