臺灣北部設施栽培小胡瓜之研究

Abstract

臺灣北部冬季因受東北季風影響，低溫陰雨連綿，日照時數低，影響設施小胡瓜之生長勢與產量，側面補光可改善其光度不足問題。適當的整枝留果可使莖葉呈最適配置，提高有限面積內之生產效率。小胡瓜於採收後期易有葉片缺鉀及落果情形，施用適當濃度之氮鉀養液可使營養生長及生殖生長達到平衡。本研究探討臺灣北部設施冬作小胡瓜適當之補光、整枝留果方法及養液氮鉀濃度，期可提高產量與品質。 小胡瓜‘秀秀’冬作栽培於臺灣大學太陽光人工光併用型植物工場，利用新調製椰纖屑及第五次使用之調製椰纖屑為栽培介質，在光強度低於30 µmol•m-2•s-1時，以T5燈(Wellypower, FH 28W/865)於側面補光至光強度250 µmol•m-2•s-1及維持光週期14 h/10 h，並以不補光為對照組。相較於不補光者，補光可增加果實頸部與中央果徑，並提高可溶性固形物濃度。補光-新椰纖屑處理比第五次使用之椰纖屑者可提早10天採收，其單株果重935.7 g、單株果數7.6條及果實抗壞血酸含量74.4 µg•g-1最高。另於臺大農業試驗場園藝分場溫網室，亦以新調製及第五次使用之椰纖屑為栽培介質；單株果重、單株果數及單果重於兩介質間無顯著差異；但以新椰纖屑種植之果實抗壞血酸含量123.7 µg•g-1高於第五次使用之椰纖屑者。 春作小胡瓜‘秀秀’以第二次使用之調製椰纖屑為栽培介質，定植於併用型植物工場及溫網室，皆未補光，子蔓留1果或2果，共四處理。栽培期間溫網室內之光強度較併用型植物工場高，故單株果重980 g、單株果數5.3條及果徑3.4 cm皆較併用型植物工場高。兩留果方式之單株果數及單株果重間皆無顯著差異，但留1果處理之果長23.3 cm大於留2果者。 秋作小胡瓜‘秀秀’定植於併用型植物工場，於營養生長期先以N300K240養液栽培，在營養生長與生殖生長同步期間，施用N400K500、N600K750及N800K1000三種氮鉀濃度養液，並搭配除子蔓、子蔓留1果及子蔓留2果三種整枝留果方式，共九種處理；單株果重及單株果數以N600K750-留2果者最高，分別為733 g及8.8條。另亦於溫網室進行上述9種處理，單株果重及單株果數則以N600K750-留1果及N600K750-留2果最佳，分別為532 g、7條及533 g、6.7條。 冬作小胡瓜‘秀秀’於營養生長期先施用N300K240養液栽培，在營養生長與生殖生長同步期間，以N600K750養液及子蔓留2果方式栽培，種植於併用型植物工場，在光強度低於30 µmol•m-2•s-1時，以T5燈於植株兩側或單側補光至光強度250 µmol•m-2•s-1及維持光週期14 h/10 h，並以不補光為對照組。另於溫網室以相同施肥及留果方式做不補光處理。溫網室不補光處理組因栽培期間均溫僅18℃，生長慢、植株最矮、產量最低，但果實可溶性固形物濃度較併用型植物工場高。併用型植物工場不補光處理組，莖徑僅3.5 mm，其徒長、植株最高。併用型植物工場補光組之葉數、莖徑、SPAD-502 value皆最佳；而雙面補光組之單株果數、單株果重、果重、果頸徑、果尾徑及抗壞血酸含量皆為顯著最高，比植物工場不補光及溫網室不補光者，分別提早10天及20天採收。 故於臺灣北部設施內，以調製椰纖屑栽培小胡瓜‘秀秀’，於營養生長期先以N300K240養液栽培，在營養生長與生殖生長同步期改施N600K750養液，於母蔓第五節以上每節留1果，每節子蔓留2果。若於冬季栽培，當光強度小於30 µmol•m-2•s-1時，以T5螢光燈於植株兩側補光至250 µmol•m-2•s-1，並維持光週期14 h/10 h，可達最佳單株果重1222 g、單株果數13條及果實抗壞血酸含量87.3 µg•g-1。

In winter of northern Taiwan, northeast monsoon results in low temperature, frequent rains and low sunshine hours which limit the growth vigor and yield of cucumber in protected structures. Supplemental interlighting could increase low light intensity. Proper fruit thinning could reach optimal arrangement of shoots and increase productive efficiency in limited area. Optimal concentrations of nitrogen and potassium in nutrient solution could balance the vegetative and reproductive growth, and prevent potassium deficiency and fruit abortion in the late stage of harvest. This research aimed to study the optimal supplemental interlighting, fruit thinning method and concentrations of nitrogen and potassium in nutrient solution in winter to increase the yield and quality of cucumber grown in protected structures in northern Taiwan. In the sunlight and artificial light type plant factory in winter at National Taiwan University, cucumber ‘Shioushiou’ was cultivated in new and the 5th-time reused ‘treated coir’, and supplementally interlighted with T5 fluorescent (Wellypower, FH 28W/865) to light intensity 250 µmol•m-2•s-1 and photoperiod 14 h/10 h or no interlighted. Neck and central width and soluble solid content in fruits of plants grown with supplemental interlighting were also higher than those without supplemental interlighting. Cucumbers grown in new treated coir with supplemental interlighting could be harvested 10 days earlier than those in the 5th-time reused treated coir, with highest fruit weight and number per plant (935.7 g and 7.6), and fruit ascorbic acid content (74.4 µg•g-1). ‘Shioushiou’ was also cultivated in new and 5th-time reused treated coir without supplemental interlighting in the greenhouse. The kind of treated coir did not affect fruit weight and number per plant and weight per fruit. The fruit ascorbic acid content (123.7 µg•g-1) from new treated coir was higher than that from the 5th-time reused treated coir. Cucumber ‘Shioushiou’ plants were cultivated in the 2nd-time reused treated coir and thinned to 1 or 2 fruits remained on the secondary suckers both in plant factory and greenhouse in spring, totally 4 treatment. Because of the higher light intensity in the greenhouse, the fruit weight and number per plant (980 g and 5.3) and fruit diameter (3.4 cm) were higher than those in the plant factory. The method of fruit thinning did not significantly affect fruit weight and number per plant. However, in 1 fruit remained treatment, the fruits were longer than those in 2 fruits remained treatment. Cucumber ‘Shioushiou’ was cultivated with N300K240 in vegetative stage, d N400K500, N600K750 and N800K1000 nutrient solution in synchronical stage of vegetative and reproductive growth, and 0, 1 or 2 fruits remained on the secondary suckers in plant factory in autumn. The highest fruit weight and number per plant (733.1 g and 8.8) were shown in N600K750-2 fruits treatment. ‘Shioushiou’ was also cultivated with the same 3 nutrient solutions and 3 fruit thinning methods in the greenhouse. The highest fruit weight and number per plant were exhibited in N600K750-1 fruit (532 g, 7) and N600K750-2 fruits (533 g, 6.7) treatment. In winter, cucumber ‘Shioushiou’ was cultivated with N300K240 nutrient solution in vegetative stage, N600K750 nutrient solution in synchronical stage of vegetative and reproductive growth, and 2 fruits remained on the secondary suckers. No, double-sided and single-sided supplemental interlighting were treated, when light intensity was below 30 µmol•m-2•s-1, supplemental interlighting with T5 fluorescent to light intensity 250 µmol•m-2•s-1 and photoperiod 14 h/10 h in the plant factory, and no supplemental interlighting were treated in the greenhouse. The low tempertature (18℃) in the greenhouse during cultivation resulting in slow growth, hence the shortest stem and the lowest yield in no supplemental interlighting treatment, but soluble solid content was higher than those in plant factory. The stem diameter was only 3.5 mm in plants grown in plant factory without supplemental interlighting resulting These plants were the most slender and the highest stem. Leaf number, stem width and SPAD-502 value in plants grown with supplemental interlighting in plant factory were the highest. The highest fruit weight and number per plant, fresh weight per fruit, neck and central width and ascorbic acid content were exhibited in fruits from double-sided supplemental interlighting treatment and could be harvested 10 days earlier than no supplemental interlighting treatment in plant factory and 20 days earlier than no supplemental interlighting treatment in greenhouse. In conclusion, in the protected structure in northern Taiwan, it is suggested cucumbers ‘Shioushiou’ planted in treated coir, with N300K240 nutrient solution in vegetative stage, N600K750 in synchronical stage of vegetative and reproductive growth, and 1 or 2 fruit(s) remained per sucker above the fifth node. In winter, supplemental interlighting with T5 fluorescent to light intensity 250 µmol•m-2•s-1 and photoperiod 14 h/10 h, the best fruit weight (1222 g) and number (13) per plant and ascorbic acid content (87.3 µg•g-1) of cucumber could be obtained in protected strutures in northern Taiwan. Index words: supplemental interlighting, treated coir fiber dust, pruning, fruit thinning, nitrogen, potassium, nutrient solution culture.