Abstract : To limit the environmental pollution associated with intensive nitrogen (N) fertilizer usage,
alternative cultural practices must be considered for crops requiring high N inputs such as rapeseed.
In this context, the effects of silicon (Si) supply on the agronomic performance of rapeseed cultivated
under field conditions with two N fertilizer levels (60 and 160 kg ha−1
) were studied. Results showed
that Si supplied in the form of silicic acid (12 kg ha−1
) has no effect on the agronomic performance of
plants cultivated with the lower N input. In contrast, in plants fertilized with 160 kg N ha−1
, Si supply
promotes the preservation of green leaves (until the flowering stage) and at harvest stage, increases
biomass, yield, and seed micronutrient concentrations (especially cobalt and iron). The agronomic
indexes show that the increase in seed yield is related to a better uptake of N from the soil by Si-treated
plants, but is not an improvement in N mobilization towards the seeds. This study showed that
Si supply combined with high N inputs (160 kg ha−1
) improves usage of N fertilizer and yield.
The possibility that a Si supply could allow for a reduction in N input without altering the yield of
rapeseed is discussed.
