Nutrient content, fat yield and fatty acid profile of winter rapeseed ( Brassica napus L.) grown under different agricultural production systems
ABSTRACT Quality features of rapeseeds (Brassica napus L.) and potential for high yielding to a major extent may be defined by improvements in agricultural engineering methods that encompass biological progress. However, this is associated with intense fertilization and application of large amounts of pesticides, which may negatively impact on environment and may decrease quality of produced food. It is thus essential to develop and improve edible oil production systems to satisfy farmer and non-threatening consumer. The aim of this study was to evaluate content of nutrients, fat yield and fatty acid profile of rapeseed grown in 5-yr monoculture and after a 4-yr break in the crop rotation system with three levels of agricultural inputs. Three levels of technologies were used: economically (low-input), moderately intensively (medium-input) and intensively (high-input), varied in N amount and S fertilization as well as protection against pests. The medium- and high-input technologies applied in the monoculture contributed to an increased percentage of oleic acid in rapeseeds (by 5.7% and 5.5%), whereas low-input and high-input technologies resulted in an increased percentage proportion of linoleic (by 11.6% and 2.1%) and linolenic acid (by 6.6% and 5.0%) in the monoculture rapeseeds. The medium-input level generated an increased proportion of arachidic (from 6.9% to 15.0%), octadecanoic (by 4.9%), linoleic (by 7.0%), linolenic (by 5.1%) and eicosadienoic fatty acids (by 17.7%) in rapeseeds cultivated in the crop rotation system. The increase in technological input level significantly changed the ratio of polyunsaturated fatty acids to linoleic and linolenic acids by 5.1% and 7.4% in both the crop rotation and by 4.2% and 7.9% monoculture systems. In general, the impact of winter rapeseed in crop sequence systems was found to have an insignificant impact on the content of macronutrients and trace elements in seeds. The highest fat yield was generated with the crop rotation system at the highest input level, whereas the lowest yield was recorded in the low-input monoculture technology.