Nitrogen and sulphur nutrition of oilseed rape and crop quality

Abstract

Spring oilseed rape was grown on a calcareous soil and fertilized with 200 kg N ha^-1, with or without 75 kg S ha^-1. Total N and S exported by the plants observed at 3 growth stages increased significantly (p < 0.05) when compared with the control. However, at maturity, total N and S uptake decreased significantly because pod abortion occurred on soil receiving only chemical N fertilizers, indicating that N metabolism was disrupted by S deficiency. Increases in seed yield were obtained in response to N and S addition, but glucosinolate level was almost 2 times higher with slurry. The accumulation of glucosinolates (GLS) in rape seeds is unfavorable to seed quality. It was concluded that the nature of fertilizers and balanced available N and S is requisite for N and S nutrition of rape (plant development, seed production and quality) and that organic residue fertilization such as slurry contributes to elevate significantly the total level of GLS.