設施小胡瓜椰纖調配介質與養液之開發

Abstract

園藝作物於設施內以介質栽培，可以減少土壤傳播性病蟲害，並解決土壤鹽分累積問題。目前生產小胡瓜(Cucumis sativus L.)常利用混和泥炭苔做為介質，但全球泥炭苔資源逐年減少，礦源溼地受嚴重破壞。椰纖屑(coir fiber dust)為農業廢棄物，來源豐富、成本低、對環境友善、理化性質與泥炭苔相似，具有替代泥炭土之潛力；但椰纖屑於使用前需先處理方能栽培作物。為有效利用椰子殼廢棄物，本研究以椰纖屑添加不同濃度之硝酸銨與白雲石灰或炭化稻殼，於設施內栽培小胡瓜，期能達到椰纖適用。以34種調配椰屑介質為胡瓜穴盤育苗介質，添加8 mM硝酸銨之淋溶椰屑80%混和20%炭化稻殼介質，比70%泥炭苔混和30%珍珠石商業用介質作，有較高的地上部(1.87 mg、167μg)與根(502μg、20.1μg) 鮮乾重、下胚軸長寬度(30.08 mm、3.2 mm)、葉片長寬度(40.28 mm、64.16 mm)、壯苗指數(0.07)與絕對生長速率(18.73)，且穴盤苗移植時間較早，於播種第10天即達89%移植率。移植後之籃耕介質，於5種泥炭苔配方中，以泥炭苔混和0.5 g.L-1苦土石灰、3 g.L-1磷礦粉與4 g.L-1棕櫚灰之配方III有最高產量(4998.8 g.plant-1)。而13種調配椰纖屑('treated' coir fiber dust)中，配方D以淋洗椰纖屑添加8 mM硝酸銨栽培小胡瓜'秀秀'，在夏作與冬作有最高之產量(2634.5 g、868.9 g)與可銷售果品質。利用D配方椰纖屑連作第三次之夏作總採收果重(2523 g)、採收良率(90.3%)及可銷售果品質均與配方III (2511 g、90.5%)無顯著差異，故此調配椰纖屑，依秋、冬、春、夏之耕作順序，至少可使用四次，供溫網室周年生產。但在冬季時，必須於太陽光型植物工場栽種小胡瓜，方能達到最佳產量(2410.32 g)與採收良率(90.3%)，且果實硬度(9.32 kg.cm-2)、可溶性固形物濃度(4.93 °Brix)、抗壞血酸含量(3823 mg.fruit-1)及果皮綠色程度(9.89)皆比露天(15.3 kg.cm-2、6.86 °Brix、4487.5 mg.fruit-1、13.95)與溫網室栽培(11.78 kg.cm-2、5.79 °Brix、4256.7 mg.fruit-1、11.03)低，可能因太陽光利用型植物工場之日溫稍低(23℃)及無日夜溫差所致。

Substrate culture horticultural crops in the protective structures can reduce soil-borne pests and salt accumulation. Mixed peat is commonly used as the substrate of cucumber (Cucumis sativus L.). But the resource peat of global declines year by year and the ore source wetland suffers serious damage. Coir fiber dust is an agricultural waste with abundance resource, low cost, the similar physical and chemical properties with peat, and is environmentally friendly, and a potential alternative to peat. However, treatment coir fiber dust is required before being used substrate. To effectively use coconut shell waste, this research studied the method to treatment method of coir dust with ammonium nitrate and dolomite or carbonized rice husk as substrates to produce cucumber in the greenhouse. Thirty four ‘treated’ coir dusts were applied as substrates to tallish used to cucumber. Comparing to seedlings more than 70% peat moss mixed 30% perlite commercial substrate. Eighty percent leaching coir fiber dust added with 8 mM ammonium nitrate mixed with 20% carbonized rice husk, showed higher fresh and dry weight of shoot (1.87 mg、167μg) and root (502μg、20.1μg), length (30.08 mm) and width (3.2 mm) of hypocotyl, length (40.28 mm) and width (64.16 mm) of leaf, seedling index (0.07), G values (18.73), and earlier transplanting time, 10 days with 89% transplant rates. For basket culture substrates after transplanting, among 5 peat moss formulas, formula III peat moss mixed with 0.5 g.L-1 dolomite, 3 g.L-1 phosphoric ore sands and 4 g.L-1 palm ash, showed the highest yield (4998.8 g.plant-1). Among 13 'treated' coir fiber dust formulas, the formula D, leached coir fiber dust added with 8 mM ammonium nitrate, exhibited the highest yield (2634.5 g、868.9 g) and marketable fruit quality in the summer and winter crops. D formula was used for three succession croppings, the total harvest fruit weight (2523 g), marketable fruit rate (90.3%) and quality were not significantly different with formula III. This 'treated' coir fiber dust could be used for annual production in greenhouse, with the sequence of fall, winter, spring and summer. In the winter, in order to achieve night yield (2410.32 g) and marketable fruit rate (90.3%), cucumber showed be grown in the sunlight type plant factory. However the fruit firmness (9.32 kg.cm-2), soluble solids concentration (4.93 °Brix), ascorbic acid content (3823 mg.fruit-1) and the greenness degree of fruit pericarp – a value (9.89) were lower than there in the open field cultivation (15.3 kg.cm-2、6.86 °Brix、4487.5 mg.fruit-1、13.95) and greenhouse (11.78 kg.cm-2、5.79 °Brix、4256.7 mg.fruit-1、11.03), probably due to the low temperature 23℃ and less day-night temperature difference in sunlight type plant factory.