The effect of technology elements on weediness and productivity of brown mustard (Brassica juncea) sowings

Modern plant protection should be as environmentally friendly as possible, therefore, agrotechnical methods should form its basis. The current paper has presented the results of three-year study (2017–2019) of the effect of nitrogen fertilizers and seeding rates on the brown mustard productivity and its ability to suppress weeds. The study was carried out in the Central steppe of the Crimea on the southern low-humus blackearth (chernozem) by the researchers of the FSBSI “Research Institute of agriculture in Crimea”. The purpose of the current study was to determine the effect of nitrogen fertilizers and seeding rates on the productivity and competitiveness of brown mustard. There was found that the amount of weeds depends on the individual weediness of the field and the conditions of moisture supply of the year. By the time the mustard was harvested, the number of weeds increased by almost 1.5 times due to the emergence of new shoots of weeds during the ripening period of mustard. There has been presented the dynamics of dry weeds weight depending on the seeding rate. There has been shown that the growth and development of weeds depends on the density of the brown mustard sowings. With an increase in the seeding rate from 0.5 to 3.0 million pieces per hectare, the dry weeds weight decreased from 180.8 to 44.3 g/m2 on average over three years. An increase in the seeding rate from 2.5 to 3.0 million pieces per hectare did not provide a significant decrease in dry weeds weight. There has been established that the optimal seeding rate for growing brown mustard in the Crimean steppe is 2.5 million pieces per hectare. At this seeding rate, mustard sowings are maximally productive (0.77 t/ha) and are characterized by a high competitive ability to weeds. There has been proven a positive effect of nitrogen fertilizers on brown mustard productivity and growth in the number of weeds. The highest mean productivity of oilseeds for three years was obtained with the application of nitrogen doses N60 and N80 and was 0.78–0.81 t/ha (on 0.28–0.31 t/ha more than that of the control). In the same variants, dry weeds weight was the highest (105.4–106.5 g/m2 )