Effect of sowing method and density on the physical properties of the seed bed and oilseed rape yield

Oilseed rape (Brassica napus L. var. napus), as a plant requiring shallow sowing, is sensitive to water deficiency in the soil during germination. The lack of rainfall results in the delay of emergence and a reduction in plant density before winter. The aim of the present study was to assess the effect of various sowing methods (sowing with the furrow method – in furrows 6–8 cm deep; direct sowing into non-cultivated soil using disc coulters and conventional sowing) on the physical properties of the seed bed and winter oilseed rape yield depending on the sowing density (40, 60, 80, 100 and 120 seeds per m2 ). The field study was carried out in 2011–2014, in Albic Luvisols with fine sandy loam texture. Furrow sowing and direct sowing provided higher seed bed moisture than conventional sowing. The use of furrow sowing resulted in the formation of a greater number of siliques per plant than in other sowing methods. Furrow sowing made it possible to produce a higher seed yield than direct sowing, however the oilseed rape yield did not increase significantly in relation to conventional sowing. The winter rapeseed yield after sowing 80–120 seeds per m2 was significantly higher than after sowing 40 and 60 seeds per m2 . When using low sowing densities (40 seeds per m2 ), furrow sowing made it possible to produce a higher seed yield than conventional sowing. The possibility of improving oilseed rape yield by differentiating sowing methods at a density of 60–120 seeds per m2 was not demonstrated.