Effect of sowing date and increasing sowing rates on plant density and yield of winter oilseed rape (Brassica napus L.) under Nordic climate conditions
AbstractA five-year investigation on overwintering of winter oilseed rape ( Brassica napus L.) cv. Wotan has been carried out in Estonia. Sowing in August was conducted four times at weekly intervals. Seeding rates of 100, 150, and 200 plants m -2 , at which respectively 47, 71, and 98 plants overwintered, gave different densities at harvest. A lower plant density (47 plants m -2 ) produced yields just as high as those with higher density (98 plants m -2 ). The optimal sowing date was mid August, which gave on average 98 plants m -2 with various plant densities. Those plants also gave higher yield (1748 kg ha -1 ), compared with the plots sown early or later in August.