不同之氮肥施用量及施用時期對結球白菜抽苔期及採種量之影響

Effect of Nitrogen Level and Timing on Time to Bolting and Seed Yield of Chinese Cabbage

剛發芽之結球白菜幼苗經5°C低溫處理20天假植於木箱，歷18天後定植於田間，以50kg/ha，150kg/ha，250kg/ha等三種不同氮肥量分三個不同時期施用，探討其對結球白菜採種之影響。試驗結束以氮肥150kg/ha一次基肥施用或分兩次施用時採種量最佳。然栽培後期（移植已是四週），施用氮肥則對種子採種量毫無影響。此結果顯示，在花芽分化及抽苔時期，適量施用氮肥，似有利於結球白菜種子之生產。

The effect of nitrogen levels and times of application with the time to bolting and seed yield on Chinese cabbage were observed. The seeds, after germination, were subjected to vernalization treatment for 20 days at 5°C. Nitrogen applied at the rate of 150 kg/ha, basal or split twice, showed the most productive seed yield of all treatments. Additional N applied at 4 wks. after transplanting did not show further beneficial effects on seed yield and its components. These results suggest that applying nitrogen between the period of differentiation and bolting stage(about 2 wks. after transplanting) seems to be most advantageous for seed production of Chinese cabbage.