Nitrogen has a crucial function, it is present in chlorophyll, chromosomes and enzymes. It is a component of countless compounds which explains its central role in growth and development. Any early nitrogen deficiency inhibits growth and reduces yield through low leaf indices and shortened vegetation duration.
Nitrogen deficiency will reduce not only the final yield but also the plant’s protein content. Conversely, excessive nitrogen leads to reduced quality: low oil content and increased glucosinolate content, especially if sulphur is not limiting.
Photosynthetic activity is the source of plant growth due to the assimilation of CO2 and the capture of solar energy. Compared to control treatment with no additional nitrogen, the photosynthesis of a fertilised plot is partly higher and lasts longer, hence more time to produce a good yield.