草莓植物工廠循環式水耕系統栽培

Abstract

植物工廠為一精密環控的設施，可以用以生產無病毒草莓苗及無農藥之果實。目前以循環式水耕系統生產走莖苗及果實的問題尚未解決；因此，本研究著重在建立循環式養液系統的栽培模式，並在溫室內評估走莖苗之後續生長。 Enshi養液作為走莖苗生產之基礎養液，N129%S90%提高29%的氮與降低10% MgSO4以評估走莖苗生產，養液配方對於母株生長沒有影響，N129%S90%單一母株每週可生產1.83子株，母株的生長趨勢在第二次養液更新後未再上升；因此建議最後一次子株採收後更新母株，平均每母株採收37子株，由Enshi養液改良的N129%S90%養液提高7.8%的子株產量。N129%S90%養液有效減少SO42-的累積與增加NO3-的供應，但養液EC及pH值變化較劇烈。走莖苗移植至溫室後，幾乎所有植株皆能順利成活。 循環式水耕系統花芽誘導最初以Enshi養液套用先前已建立之非循環式系統之生殖生長模式，評估‘桃園一號’與‘長柄’草莓的生殖生長，兩品種最終可見花序比率皆僅有12%。由於誘導結束時恰逢養液更換，開花期氮肥驟然提高，多數植物回轉進行營養生長。因此規劃養液減氮試驗，在初始及補充養液中降低Enshi 養液的氮含量。N75%+N50%及N75%+N75%分別恢復100%及93.33%植株開花，但減氮系統花序出現較慢，尤其是N75%+N75%。養液減氮試驗中的Ca2+及Mg2+能維持穩定的濃度，而SO42-濃度持續上升，K+及NO3-在減氮養液中供應較少，果實發育初期濃度不足，即使更換養液，採收時間仍比對照組非循環系統晚6至7日，且平均果重僅有16 g，顯著低於非循環系統的20 g。減氮養液雖可以解決循環式系統花芽誘導的問題，但營養不足以提供良好的果實生產，因此以循環式養液系統利用再誘導植株生產第2期果尚不可行。循環系統產果的系統仍須進一步研究，在花序誘導率問題解決後，還要避免造成植株營養缺乏。

Plant factory, a sophisticated environmentally controlled facility, could facilitate the production of virus-free strawberry daughter plants and pesticide-free fruits. At present, the problem caused by recirculating hydroponic system in daughter plants and fruits production has not yet been solved. Therefore, this study focused on the establishment of recirculating hydroponic system in strawberry daughter plants and fruit production. The growth of daughter plants was also evaluated in the greenhouse. N129%S90%, Enshi solution with 29% nitrogen enhancement and 10% MgSO4 decrease, was evaluated for daughter plants production. No difference between N129%S90% and Enshi solution in mother plants’ growth. N129%S90% enabled 1 mother plant to produced 1.83 daughter plants per week in average. The growth of the mother plants was not promoted after the second solution renewing; therefore, the mother plants were suggested to be renewed after the final harvest, and each mother plants produced 37 daughter plants in average. The Enshi solution modification, N129%S90%, increased 7.8% of daughter plant production. N129%S90% nutrient solution effectively decreased the SO42- accumulation in addition to supply more NO3-, but the variation of EC and pH value were larger. Nearly all the daughter plants grew well after transferring to the greenhouse. The flower induction in recirculating hydroponic system was first evaluated both 'Taoyuan No.1' and 'Changbin' strawberry by direct fitting the reproduction model previously built in non-recirculation system which Enshi solution was used. The final inflorescence ratio of both cultivars was only 12%. Due to the solution renewing was at the end of floral induction, the dramatic increase of nitrogen forced most of plants turn back to vegetative growth. Therefore, a nitrogen-reduced nutrient solution experiment was programed. We reduced nitrogen content of Enshi solution in both the initial and supplemental nutrient solution. N75%+N50% and N75%+N75% recovered the final inflorescence to 100% and 93.33%, respectively, but the appearance of inflorescence was slower in nitrogen-reduced nutrient program, particularly N75%+N75%. The concentration of Ca2+ and Mg2+ maintained stable and SO42- was accumulating throughout the experimental period. The K+ and NO3- were less supplement in nitrogen-reduced nutrient solution and plants suffer depletion at the early fruit development stage which might resulted in delaying harvest by 6 to 7 days compared to non-recirculating control, and the delay could not prevent even if we renewed the solution. The average fruit weight was 16 g, which was significantly smaller than the average weight 20 g of non-recirculating system. In recirculating system, the nitrogen-reduced nutrient program could solve the problem of flower induction but the nutrient was not sufficient to offer good fruit production; therefore, the re-induced plants for the production of second bunch of fruits by recirculating hydroponic system was not applicable. Producing strawberry fruits in recirculating hydroponic system required more study to avoid nutrient deficiency after the floral induction problem was solved.