Factors affecting nitrogen concentration in spring oilseed rape (Brassica napus L.)

Abstract

The effect of the duration of the growth season, meaning daily temperature, precipitation rate, growing degree in days, nitrogen rates and application time, stand population density, soil nitrogen content and the interaction among these factors on nitrogen concentration in spring oilseed rape plants of aboveground dry matter. During the vegetative growth season, mature seeds and straw were studied in field experiment with spring oilseed rape (Brassica napus L.) cv. Star over five years. It was found that nitrogen concentration was the highest in the youngest plants. The increase of duration in growth season and precipitation rate had a negative effect on nitrogen concentration in mature seeds. Meanwhile, the increase in growing degree-days and mean daily temperature positively affected seed nitrogen concentration. The relationships between nitrogen concentration in spring oilseed rape plants at different growth stages and climate records was found. Stand population density occurred having a rather negligible effect on nitrogen concentration. Nitrogen fertilizer rates showed strong and positive effect on nitrogen concentration in aboveground dry matter as well as in seed and straw. With the delay of nitrogen application time concentration of nitrogen was increasing.