有機栽培制度對蕉園土壤環境及蕉果後熟品質之影響

Effects of Organic Farming on Soil and Banana Postharvest Quality

以慣行栽培蕉園為對照，進行‘北蕉’及‘寶島蕉’有機栽培蕉園土壤分析、黃葉病罹病調查、蕉果品質測定及風味品評試驗。試驗結果顯示，香蕉園管理採行有機栽培模式有（1）增加土壤陽離子交換能量、有機碳、微生物生質碳及微生物生質氮含量；（2）降低土壤總體密度，增加土壤孔隙度；（3）增加土壤微生物如細菌、真菌、游離固氮菌及溶鈣磷菌之密度；（4）增加土壤團粒穩定度；（5）維持土壤酸鹼值偏微鹼性；及（6）降低有機栽培蕉株之黃葉病罹病率等功效。香蕉園採行有機栽培管理可改善土壤之物理、化學及微生物特性，提升土壤品質。蕉果品質測定及風味品評結果顯示：（1）有機栽培管理可提高在夏、秋兩季生產‘北蕉’、‘寶島蕉’之果肉強度（穿刺阻力），增進口感；（2）有機栽培管理可提升‘北蕉’秋蕉及‘寶島蕉’冬蕉之可溶性固形物含量，惟在各季節蕉中，有機栽培‘北蕉’、‘寶島蕉’之果肉水份含量均和慣行栽培無差異；（3）有機栽培蕉果在後熟處理中之果皮轉色較慣行栽培略快；（4）有機栽培夏、秋蕉之櫥架壽命略短，冬、春蕉則較長；（5）有機栽培蕉之口感、甜度及香氣等風味與慣行栽培香蕉無明顯差異。 Soil analysis, Fusarium wilt incidence of banana orchards, postharvest quality and sensory test of 'Pei-chiao' and 'Formosana' under organic farming were proceeded. Results from soil analysis indicated that organic farming practices had positive effects on soil quality, as compared to conventional farming, by (1) increasing cation exchange capacity, organic carbon, microbial biomass carbon and nitrogen of soil, (2) lowering soil bulk density and in turn increasing soil porosity, (3) increasing the population densities of soil bacteria, fungi, non-symbiotic nitrogen-fixing bacteria, and calcium phosphate-solubilizing bacteria, (4) enhancing soil aggregate stability, and (5) adjusting soil pH to the range of mild alkalinity. A markedly lower Fusarium wilt incidence also resulted from the organic farming practices, however, attention should be paid to the rise of soil salinity in the banana orchard due to the application of organic fertilizers. Results from postharvest quality evaluation and sensory test on 'Pei-chiao' and 'Fromosana' revealed that (1) organic farming practices raised the pulp penetration resistance of summer and autumn bananas of both cultivars, and offered a better mouthfeel, (2) organic farming practices increased the total soluble solids of autumn 'Pei-chiao' and winter 'Formosana', however it did not cause difference in pulp water content between the two systems, (3) the rate of peel discoloration during postharvest maturing was slightly faster for organic bananas, (4) the shelf life was shorter for organic summer and autumn bananas, and longer for organic winter and spring bananas, (5) the mouthfeel, sweetness and flavor of the organic bananas were as good as those of the conventional bananas, sometimes even better.