氮肥施用量對北蕉生育、產量與品質之影響

The Growth, Yield and Postharvest Quality of Giant Cavendish as Affected by Rate of Nitrogen

在有機質含量2%的坋質壤土新植北蕉（Giant Cavendish, AAA group）組織培養苗，肥料施用量分別為每株每年尿素0，205，410及820公克。試驗結果顯示，施用205公克尿素應足夠蕉株全生育期所需之氮量；和施用410公克與820公克／年／株比較，蕉株的生長與發育並未受阻，抽穗亦正常；平均果串重和可溶性固形物含量之差異雖不顯著，卻有提高的趨勢。少施氮肥還可增加櫥架壽命，延長商品價值。從肥培管理的觀點而言，蕉園中普遍施用過量氮肥是台蕉品質變劣的主要原因之一；為確保香蕉外銷事業的永續經營，恢複台蕉原有優良風味，降低生產成本，減少氮肥施用是簡單可行的辦法。經由土壤分析與植體營養診斷，顯示磷肥仍有減施空間，鉀肥則可酌量增施。

Field experiments on the effects of nitrogen rate on the growth, yield and fruit quality of banana 'Giant Cavendish' (Pei-Chiao) were conducted in southern Taiwan. Results indicated that tissue cultured plantlets grown in an alluvial soil with 2% of organic matter, and with nitrogenous fertilizer applied at one half (1/2N) of the recommended rate (1N:410 grams of urea/plant/year) i. e., 94 grams of nitrogen, was optimal to the physiological requirements of the entire crop cycle. At this rate, the nutrient status, growth rate, shooting time and bunch weight of banana plants were about the same as those receiving higher rates. However, the fruit quality in terms of shelf life and total soluble solids was significantly improved at 1/2N, as compared with treatments of 1N and 2N. Upon ethylene treatment, uneven degreening in banana hands occurred at about the same level among treatments of 1/2, 1N, and 2N, but a much lower level in treatment receiving no urea. Therefore, it is suggested that the current rate of nitrogen for banana plantations be reduced reduced from 410 to 205 grams of urea/plant/year.