Peculiarities of feeding winter rapeseed
To obtain 1 ton of rapeseed grains with the relevant mass of straw the rape absorb from soil 50-60 kg of N, 20-25 kg of P2O5, 40-50 kg of K2O, which is much more than the absorption of other cultures. In the soils with average level of provision of plants with movable forms of basic nutrients, optimum rate of mineral fertilizers is N 80-120, P 60-90, K 60-90. An important role is also played by sulphur which is necessary for the absorption of nitrogen and magnesium the provision of which determines the yield of grains and the oil content in them. In autumn magnesium stimulates transportation if sugars from the leaves to the roots which results in forming stronger root system and increased resistance of plants to low temperatures during wintering. It is important for rapeseed throughout the vegetation. In early stages it facilitates the strengthening of the root system, accumulation of sugars in the root collar and its growth. The most acute need in this micro-nutrient occurs both before and during the blooming, that is why the lack of boron can be found in these stages. The lack of boron in autumn impedes the growth and development of the root system and growing point of winter rapeseed, lessens the accumulation of sugars and other high energy substances, their transportation to root collar and worsens the resistance of plants to frost and winter and the wintering in general which causes deformation and hollow heart in the root system of rapeseed, cracked stems, stops blooming, pollination and insemination of flowers and results in lesser yield. Boron facilitates the absorption of calcium from the soil by rapeseed. The vegetation period of the winter rapeseed can be assumed to consist of 3 basic “critical” stages during which the biggest need in nutrients (especially micro-nutrients) can be observed:
1 – formation of leaf rosette (foliar feeding allows to prepare the plant for winter);
2 – stem formation (ensures the activation of morphophysiological processes);
3 – bud inception and development as well as the end of blooming (facilitates the processes of blooming, grain formation and development).