溫室介質栽培花胡瓜之節水省肥滴灌研究

Abstract

胡瓜為世界重要經濟作物之一，亦為臺灣夏季重要果菜之一，其乾旱耐受性較弱。臺灣受到地理環境限制及氣候變遷影響，水資源供應問題愈趨嚴峻。本研究以花胡瓜‘秀秀’(Cucumis sativus ‘Shiou Shiou’)為試驗材料，探討溫室自動化肥灌栽培之介質體積含水量(volumetric water content, VWC)與養液矽(silicon, Si)添加量對其生長、產量、品質與水分利用效率(Water use efficiency, WUE)之影響，得知適當節水省肥模式。秋作、冬作花胡瓜於營養生長期皆以介質VWC 20 %為肥灌起始閾值，冬作並於養液中添加200 mg·L-1 Si，而於生殖生長期皆以介質VWC 40 %為肥灌起始閾值，皆對單株產量(分別為1690.7 g、504.1 g)、果實外形與單果重皆無負面影響，分別可節省7%與25.95%養液量，但未顯著提升水分利用效率。夏作花胡瓜於營養生長期皆以介質VWC 40 %為肥灌起始閾值，而生殖生長期分別以介質VWC 40 %、VWC 30 %、VWC 20 %、VWC 10 %為肥灌起始閾值；其中VWC 40 %組有最高單株產量2009.5 g與果實總可溶性固形物4.9°Brix；VWC 20 %組有最高水分利用效率29.17 g·L-1，相較於對照組可節省45.52%養液量，雖然單果重116.7 g與VWC 40 %、VWC 30 %兩組無顯著差異，但單株產量1269.1 g顯著低於對照組；而VWC 10 %組產量最低，且平均單株果重顯著低於各組。秋-初冬作花胡瓜於營養生長期皆以介質VWC 40 %為肥灌起始閾值，而生殖生長期以介質VWC 20 %與40 %為肥灌起始閾值，並皆於養液分別添加0、100、200 mg·L-1矽；其中VWC 20 %+200 mg·L-1 Si組之水分利用效率24.2 g·L-1顯著高於VWC 40 %+0 mg·L-1 Si、VWC 40 %+100 mg·L-1 Si以及VWC 40 %+200 mg·L-1 Si組，但與VWC 20 %+0 mg·L-1 Si、VWC 20 %+100 mg·L-1 Si組無顯著差異，其單株產量1008.5 g與其他處理皆無顯著差異，栽培者可視需求施用200 mg·L-1矽。春-初夏作花胡瓜栽培施予5種處理，包括：全期以介質VWC 40 %為肥灌起始閾值(T1)、全生長期以介質VWC 20 %為肥灌起始閾值(T2)、全生長期以介質VWC 20 %為肥灌起始閾值且於生殖生長期養液添加200 mg·L-1矽(T3)、營養生長期以介質VWC 10 %而生殖生長期以介質VWC 20 %為肥灌起始閾值(T4)、營養生長期以介質VWC 10 %而生殖生長期以介質VWC 20 %為肥灌起始閾值且於生殖生長期養液添加200 mg·L-1矽(T5)；5種處理之單果重與產量間皆無顯著差異，但T2組於果實官能品評之香氣、甜味與總評，皆比其他處理組佳，且水分利用效率達58.14 g·L-1，相較於對照組可節省51.23 %養液量，單株產量達1794.9 g。故於臺北地區溫室以介質栽培花胡瓜，建議2-5月全生長期以VWC 20 %為肥灌起始閾值；6-10月於營養生長期以VWC 40 %、生殖生長期以VWC 20 %為肥灌起始閾值；8-10月可視需求施用200 mg·L-1矽；上述3種肥灌模式皆不影響單果重且具高水分利用效率，可達到節水省肥目標。而11月至翌年1月因低溫不適合栽培花胡瓜。

Cucumber (Cucumis sativus) is one of the important economic crops in the world. It is also one of the important fruit vegetables in Taiwan, and is sensitive to drought stress. Due to geographical constraints and climate change, water resource supply is becoming more and more restricted in Taiwan. In this study, Cucumis sativus 'Shiou Shiou' was used as experiment material. The effects of substrate volumetric water content (VWC) and the silicon (Si) supplementation in nutrient solution through automatic drip fertigation in the greenhouse on plant growth, yield, quality, and water use efficiency (WUE) were investigated to know the appropriate water- and fertilizer-saving model. Substrate VWC 20 % in vegetative growth stage and substrate VWC 40 % in reproductive stage were set as drip fertigation thresholds both in fall and winter, and 200 mg·L-1 Si was also supplied in nutrient solution in winter. No negative impact was shown on yield per plant, fruit shape and single fruit weight. Although 7 % and 25.95 % of fertigation amount were saved respectively, WUE was not significantly improved. In summer, substrate VWC 40 % in vegetative growth stage, and substrate VWC 40 %, VWC 30 %, VWC 20 % and VWC 10 % in reproductive stage were set as drip fertigation thresholds in summer. VWC 40 % treatment had the highest yield per plant 2009.5 g and fruit tatal soluble solids 4.9 °Brix. However, VWC 20 % treatment showed the highest WUE 29.17 g·L-1, 45.52 % fertigation amount reduced, with fresh weight per fruit 116.7 g not significantly different from that in VWC 40 % and VWC 30% treatments, and yield per plant 1269.1 g significantly lower than control. VWC 10% treatment exhibited the lowest yield and fruit weight per plant. In fall-winter, substrate VWC 40% in vegetative growth stage, and substrate VWC 20 % and 40% in reproductive growth stage were set as fertigation thresholds with 0, 100 and 200 mg·L-1 of Si supplied in nutrient solution for 2 VWC treatments, respectively. The VWC 20 %+200 mg·L-1 Si treatment showed the highest WUE 24.2 g·L-1, which was significantly higher than VWC 40 %+0 mg·L-1 Si, VWC 40 %+100 mg·L-1 Si and VWC 40 %+200 mg·L-1 Si treatments, but not significantly different from that in VWC 20 %+0 mg·L-1 Si, and VWC 20 %+100 mg·L-1 Si treatments. However, the yield per plant 1008.5 g of VWC 20 %+200 mg·L-1 Si treatment was not significant different from others. Therefore, the grower could apply 200 mg·L-1 silicon when needed. Finally, 5 fertigation methods were applied in spring-summer, including T1 and T2: substrate VWC 40 % and 20 % as fertigation thresholds in whole cultivation period, respectively; T3: substrate VWC 20 % as fertigation threshold in whole cultivation period and 200 mg·L-1 Si supplementation in nutrient solution in reproductive stage; T4: substrate VWC 10% in vegetative stage and substrate VWC 20 % in reproductive stage as fertigation threshold; T5: substrate VWC 10 % in vegetative stage and substrate VWC 20 % in reproductive stage as fertigation threshold, and 200 mg·L-1 Si supplementation in nutrient solution in reproductive stage. None significant difference was shown on weight per fruit and yield per plant among 5 treatments. However, T2 treatment showed better aroma, sweetness and overall evaluation in fruit organoleptic evaluation, with WUE 58.14 g·L-1, yield per plant 1794.9 g and 51.23 % fertigation amount saved compared to the control. Hence, for cultivating cucumber with substrate in the greenhouse in Taipei area, from February to May it is suggested VWC 20 % set as drip fertigation threshold in whole cultivation period. While from June to October, VWC 40% in vegetative growth stage and VWC 20 % in reproductive growth stage set as drip fertigation thresholds were recommended. The grower could apply 200 mg·L-1 silicon when needed from August to October. Through 3 models, high WUE and fresh weight per fruit could be obtained, and water- and fertilizer-saving achieved for cucumber. Due to low temperature, from November to next January is not suitable for cultivating cucumber.