Adequate amount of essential plant nutrients and plant density are vital factors influencing the productivity of
oilseed rape (Brassica napus L.). Field experiments were conducted in southern China to study the influence of
different fertilizing levels and planting densities on the seed yield, chlorophyll content and some growth traits of
winter oilseed rape. Five fertilizing levels and six planting densities were set in a randomized block design. The
tested planting densities were D1, D2, D3, D4, D5 and D6 with 7.5 × 104
, 15 × 104
, 22.5 × 104
, 30 × 104
, 37.5
× 104 and 45 × 104 plants ha−1
, respectively. The tested fertilizing levels were F0 (control without fertilization), F1 (N = 60, P2O5 = 30, K2O = 52.5, S = 3.75, B =0.3 kg ha−1
), F2 (N = 120, P2O5 = 60, K2O = 105, S
= 7.50, B =0.60 kg ha−1
), F3 (N = 180, P2O5 = 90, K2O = 157.5, S = 11.25, B =0.90 kg ha−1
) and F4 (N =
240, P2O5 = 120, K2O = 210, S = 15, B =1.20 kg ha−1
). The results showed that there were close relationships
between the seed yield and fertilizing levels × planting densities. Below the fertilization level of F2, the seed
yield increased as the planting density increased. Application of F3 caused a seed yield decline when the planting
density surpassed 37.5 × 104 plants ha−1
. The tested fertilizing levels caused remarkable increases in the seed
yield but the plant density had little effects. The highest seed yield (2487 kg ha−1
) was recorded in F4D3
followed by F4D1 (2308 kg ha−1
), F4D5 (2303 kg ha−1
) and F3D6 (2302 kg ha−1
); while the minimum yield was
obtained from the unfertilized soil treatments. The current research paper highlighted the importance of balanced N, P, K, S and B application under the different plant densities in winter oilseed rape. The individual
growth of plants compensated the low plant density, but increasing the fertilization rates caused remarkable
increases in the oilseed rape, suggesting that optimum nutrients rates are a critical factor in seed yield production.