溫室介質栽培甜椒之節水省肥滴灌研究

Abstract

甜椒(Capsicum annuum L.)為臺灣重要經濟果菜作物之一，栽培時需灌溉充足，方能獲得優良的果實品質與產量。近年農業灌溉水缺乏問題日益嚴峻，亟需改善灌溉模式，提高水分利用效率(water use efficiency)。本研究於國立臺灣大學溫室以90%泥炭土與10%珍珠石之介質栽培甜椒‘和生-101’，使用WatchDog迷你氣象站搭配土壤水分感測器，設定養液開始自動滴灌之介質體積含水量(volumetric water content, VWC)閾值，探討植株生長、果實品質、產量及水分利用效率。栽培全期介質體積含水量試驗共施以四種肥灌方法，對照組在VWC低於40%時開始肥灌，另分別在VWC低於30%、20%和10%時啟動肥灌；則春夏作在介質VWC低於30%時、秋冬作在低於20%時即自動肥灌，其果實品質與單株產量(分別為1797.9 g和1254.1 g)皆與對照組無顯著差異，比對照組分別減少17.44%與68.89%肥灌量，且秋冬作水分利用效率21.67 g∙L-1顯著提高，達節水省肥效益。秋冬作生育階段節水省肥試驗共施以四種肥灌方法，對照組為全期以VWC 40%為肥灌起始點；另分別於營養生長期、開花果實肥大期和果實成熟期以VWC 30%為肥灌起始點，其餘生育期皆在VWC低於40%時啟動肥灌；分別於各生長期節水省肥皆不會對營養生長與果實品質造成負面影響，且單株產量與對照組無顯著差異，分別為1966.1 g、1800.1 g和1841.3 g，但是水分利用效率未顯著提升，僅節水省肥4.3%~11.3%。春夏作生育階段節水省肥試驗共施以八種肥灌方法，對照組為全期分別以VWC 40% (CK40)及VWC 30% (CK30)為肥灌起始點；另六種處理包括：分別於營養生長期、開花與果實肥大期、果實成熟期以VWC 20%或10%為肥灌起始點，其餘生育期皆以VWC 30%；結果顯示，分別僅於營養生長期、開花果實肥大期或果實成熟期以VWC 20%為肥灌閾值，其他生育期皆以VWC 30%為肥灌閾值，可維持與對照組無顯著差異之良好單株產量，分別為1167.2 g、1231.8 g和1195.8 g，減產率僅2.95%~8.04%，並分別顯著提高水分利用效率至16.69 g∙L-1、19.38 g∙L-1及18.85 g∙L-1，比對照組分別節省58.2%、61.9%及62.1%肥灌量，皆達節水省肥目標；而春夏作營養生長期或果實成熟期皆能耐受較低之肥灌閾值VWC 10%，其餘生育期以VWC 30%為肥灌閾值，分別可節省63.9%及65.1%肥灌量，單株產量(1073.7 g及985.9 g)與對照組無顯著差異，但減產率較高(15.41%和22.32%)。綜之，甜椒‘和生-101’在臺北地區溫室以90%泥炭土與10%珍珠石之介質栽培，建議2~7月之春夏作於營養生長期、開花果實肥大期或果實成熟期選擇任一時期，以介質體積含水量20%為肥灌起始點，其餘時期皆以體積含水量30%為肥灌閾值；而8月~翌年1月之秋冬作於栽培全期以介質體積含水量20%為肥灌閾值；兩種模式皆不影響產量與果實品質，並達到節水省肥目標。

Sweet pepper (Capsicum annuum L.) is one of the important economic fruit vegetable crops in Taiwan. Sufficient irrigation is required to obtain good fruit quality and yield. In recent years, lacking of agricultural irrigation water has become more and more serious. It is necessary to improve the irrigation model and enhance water use efficiency. In this study, sweet pepper ‘SPR-101’ was cultivated with 90% peat and 10% perlite substrate in the greenhouse of National Taiwan University. The WatchDog mini weather station was equipped with the soil moisture sensor to automatically control the drip fertigation system by setting substrate volumetric water content as starting threshold. Plant growth, fruit quality, yield and water use efficiency were investigated. Four drip fertigation methods were utilized in whole cultivation phase substrate volumetric water content experiment. In control (CK), drip fertigation was started from substrate volumetric water content (VWC) below 40%. In other 3 treatments, drip fertigation was started from VWC below 30%, 20% and 10%, respectively. For thresholds of VWC 30% during spring-summer cultivation and VWC 20% during autumn-winter cultivation, good fruit quality and yield per plant (1797.9 g and 1254.1 g) were not significantly different from the control, and 17.44% and 68.89% of water and fertilizer were reduced, respectively; water use efficiency was also significantly increased to 21.67 g∙L-1 during autumn-winter cultivation. In experiment for fertigation saving in different growth stages in autumn-winter cultivation, control started fertigation at VWC below 40% during whole growth period; VWC 30% was set as threshold in vegetative growth stage, flowering and fruit enlargement stage and fruit ripening stage, respectively, and VWC 40% in non-treated period. Fertigation saving in each growth stage, vegetative growth, fruit quality and yield per plant (1966.1 g, 1800.1 g and 1841.3 g) were not lower comparing to the control (VWC 40%). But water use efficiency did not significantly increase, and only 4.3%~11.3% of fertigation amount were reduced. In experiment for fertigation saving in different growth stages in spring-summer cultivation, eight drip fertigation methods were applied. CK40 and CK30 started fertigation at VWC below 40% and 30% during whole growth period, respectively. VWC 20% or VWC 10% were set as fertigation thresholds in the vegetative growth stage, flowering and fruit enlargement stage, fruit ripening stage, respectively, and VWC 30% in the rest of the growth stage. The results showed fertigation above VWC 20% only in vegetative growth, flowering and fruit enlargement stage or fruit ripening stage, and VWC 30% in the non-treatment stage, both could have as good yield per plant (1167.2 g, 1231.8 g and 1195.8 g) as the control; the yield reduction rate were only 2.95%~8.04%. Water use efficiency were enhanced to 16.69 g∙L-1, 19.38 g∙L-1 and 18.85 g∙L-1 and water and fertilizer consumption were reduced for 58.2%, 61.9% and 62.1%, respectively. In vegetative growth or fruit ripening stage, fertigation threshold could be lowered to VWC 10%, with VWC 30% in the non-treatment stage, resulting 63.9% and 65.1% of water and fertilizer reduced, and the yield per plant (1073.7 g and 985.9 g) not significantly different from the control. However, the yield reduction rate were higher (15.41% and 22.32%). In conclusion, for sweet pepper ‘SPR-101’ cultivated with substrate in the greenhouse in Taipei area, in spring-summer (February to July), VWC 20% set as threshold of drip fertigation only in one of vegetative growth stage, flowering and fruit enlargement stage or fruit ripening stage, and VWC 30% in other stages; while in autumn-winter (August to next January), substrate VWC 20% as threshold in the whole cultivation phase, not only could obtain good yield and fruit quality, but also save water and fertilizer.