香蕉園有機栽培管理

Organic Farming on Banana Plantation

香蕉園進行有機農法管理連續四作以後，各品種蕉株之累積抽穗情形與慣行栽培蕉株差異顯不顯著，組織培養苗蕉株在有機栽培和慣行栽培間之抽穗差距有縮小趨勢。有機栽培蕉株葉片中之氮、鉀、鈣、鎂含量雖較慣行栽培為低，較第一年種植之有機植株亦略低，惟均在「充足」範圍內，慣行栽培之植株亦有同樣情形。有機栽培蕉株在抽穗時之平均健葉數較慣行蕉株少1.0-2.5葉，顯示葉片保護之效益與資材之篩選有相當空間。在供試品種中，耐黃葉病品種‘台蕉三號’之產量偏低，作為有機栽培之適栽品種潛力不高。有機栽培青熟蕉催熟後之轉色速率、櫥架壽命與可溶性固形物和慣行栽培蕉並無顯著差異。有機蕉園與慣行蕉園土壤之有機質含量均略有增加，有機蕉園之土壤酸鹼值及電導度較慣行栽培穩定，其有效性礦物營養成份亦維持在可正常生長之界限內。有機栽培蕉株之黃葉病罹病率雖由0.6%上升至9.1%，仍遠較慣行栽培蕉株之31%為低。有機農法不僅保育自然資源，有機香蕉之生產淨收入為慣行香蕉之兩倍以上，顯示以有機農法從事香蕉生產之經濟可行性。 After four consecutive years of cropping at the TBRI experimental plot, the cumulative shooting rate of banana plants under organic farming could be controlled similarly to that under conventional farming. The difference in cumulative shooting rate of tissuecultured plants between organic and conventional plots decreased with time. Nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) contents of banana leaves sampled from organic plants were at the lower level of a ”sufficient” range, same results were also found for the conventional plants. At shooting stage, the average healthy leaf numbers of an organic plants were less than those of a conventional plants by 1.0-2.5 leaves, indicating more efficient materials were required for the foliar disease control in the organic plot. Due to a low yield potential, cultivar 'TaiChiao No.3' was evaluated to be not economic for organic farming. In the postharvest quality, there were no significant differences between two cropping systems, as related to peel discoloration rate, shelf life, and soluble solids. A slight increase in soil organic matter was found in both cropping systems, however, less fluctuation in soil pH and electrical conductivity (EC) was detected in the organic plot, as compared to those in the conventional plot. Macroand micronutrients of both soil systems were within proper ranges for an optimal banana growth. The disease incidence of Fusarial wilt in organic plot went up from 0.6% to 9.1% after four consecutive croppings, which was far lower than 30.7% of the conventional plot. The economic feasibility of organic farming system for banana production was well supported by the net profit achieved from a TBRI-run organic banana plantation.