Effect of differential N and S competition 1 in inter- and sole cropping of Brassica species and lettuce on glucosinolate concentration

Summary

Field and greenhouse pot experiments were conducted to evaluate the potential to use intercropping as an alternative method to increase glucosinolates in Brassicas by manipulating nitrogen (N) and sulphur (S) balance by intercropping with lettuce (Lactuca sativa L. var. capitata). In both experiments, four combinations of N and S fertilization were used. In the field experiment no effect of intercropping on the total glucosinolates was found as the growing lettuce was strongly inhibited by the presence of broccoli (Brassica oleracea L. var italic). The reduction in neoglucobrassicin in broccoli from intercropping was probably attributed to the lower N concentrations in broccoli florets. In contrast to this, in the pot experiment both total and individual glucosinolate concentrations in red leaf mustard(Brassica juncea L.) increased by intercropping. Fertilization treatments influenced glucosinolate concentrations in both experiments, and an N by S interaction was observed.