Split dose fertilization with urea increases glucosinolate contents in white cabbage (Brassica oleracea L. var. capitata) under experimental pot conditions

Abstract

Split dose nitrogen (N) and sulfur (S) applications are a common agricultural practice as safe choices for environmental purposes. However, the effects of split dose practice on glucosinolate (GLS) biosynthesis remain elusive. The objectives of the present study were to investigate the timing effects of N and S fertilizer use on GLS biosynthesis in white cabbage plants. Therefore, timed split and non-split N treatments were combined with three S treatment levels or timed split and non-split S treatments.Split N dose treatments increased indole and total GLS concentrations, whereas non-split N treatments increased aliphatic GLSs. The effect of S was dependent on N treatment. Split N treatment resulted in enhanced GLS concentrations, which increased from 4351 to 7208μgg−1 dry weight (DW) with increasing S treatment; and with split and non-split S treatments, GLS concentrations ranged from 5836 to 7208μgg−1 DW. Non-split N treatment had no effect and GLS concentration was measured at 5510μgg−1 DW.Results indicated that equal N availability (split dose) facilitated an increased plant response to S and a subsequent effect on GLS biosynthesis compared to unequal N availability (non-split dose). In terms of practical crop management, the timing of fertilizer addition to white cabbage can be used to optimize GLS concentrations.