Soil Nmin target values for Chinese onion at different growth stages

Abstract

To promote vegetable growth and minimize environmental pollution, the key of nitrogen recommendations is to determine optimum inorganic nitrogen rate in root-layer soil in different growth phases. In a field experiment, nitrogen fertilizer was applied to Chinese onion (Allium fistulosum L. var. giganteam Makino.) at different nitrogen fertilizer rates (N 0, 120, 240, 360 and 480 kg ha-1) to test nitrogen balance and response in soil-plant system. In this experiment, the highest yield of Chinese onion was obtained when nitrogen fertilizer rate was N 310 kg ha-1. According to analysis of yield, environment, benefit and our current production practice, N3 treatment was the best nitrogen fertilizer value in the experiment. The estimated soil Nmin target values were 83, 140, 140 and 230 kg ha-1 for basal fertilizer, NO.1 side dressing, NO.2 side dressing and NO.3 side dressing stages respectively.