土壤介質添加保水劑對花壇植物生育及水分利用之影響

Abstract

作物栽培過程中，經常面臨缺水的逆境；如何減少農業用水以充分利用水資源，是現今所需面對的重要課題。當花壇植物種植於較小的盆器中時，對水分逆境較為敏感。由於以保水劑種植作物可降低灌溉用水量、增加苗木移植成活率及促進植物生長與開花，因此本研究擬探討保水劑種類與施用劑量對花壇植物生長及育苗之影響，以期能對花壇植物之生長及抗乾旱逆境有所幫助。 馬纓丹 (Lantana camara) 以三種保水劑Alcosorb® (AS)、TerraCottem® (TC) 及Taisap DC-386A (TS) 分別混合添加6或12 g•L-1於砂質壤土 (田土) 及泥炭苔：真珠石 (3號)：蛭石 (3號) = 2：1：1 (體積比) (泥炭苔混合介質) 中栽植，結果顯示：無論於田土或泥炭苔混合介質中添加何種廠牌之保水劑，皆能增加其介質含水量及EC值，且降低介質硬度。栽培介質添加保水劑皆能減輕乾旱逆境對馬纓丹植株生長之不良影響，尤以田土為栽培介質時，添加12 g•L-1保水劑AS或添加6及12 g•L-1 TS者之表現較佳；而以泥炭苔混合介質種植時，添加12 g•L-1保水劑Alcosorb®者之表現較佳。 夏蓳‘小丑酒紅’ (Torenia fournieri ‘Clown Burgundy’) 以三種保水劑AS、TC及TS分別添加6或12 g•L-1於泥炭苔混合介質中栽植，結果顯示：以添加12 g•L-1 TC與6 g•L-1 AS較能減輕乾旱逆境對植株生長之不良影響。另以保水劑AS分別混合添加3、6、9及12 g•L-1於泥炭苔混合介質中栽植，以添加3 g•L-1保水劑者之株高、幅寬及抗乾旱逆境之綜合表現較佳。 非洲鳳仙花‘音樂’ (Impatiens wallerana ‘Accent’)、四季秋海棠‘超級奧運粉紅’ (Begonia semperflorens-cultorum ‘Super Olympia Pink’) 及香蓳菜 (Viola cornuta) 以3 g•L-1保水劑AS混合添加 (Mix-AS) 及底部添加 (Bottom-AS) 於泥炭苔混合介質中，並栽植於日夜溫30/25 ℃及20/15 ℃環境下，結果顯示：添加保水劑AS對非洲鳳仙花‘音樂’於兩日夜溫下之抗乾旱逆境較無助益，而四季秋海棠‘超級奧運 粉紅’與香蓳菜皆以涼溫下混合添加保水劑AS之生長表現較佳。又黃金金露華 (Duranta repens ‘Golden Leaves’) 以9 g•L-1保水劑AS混合添加於田土及泥炭苔混合介質中栽植，結果顯示：田土添加保水劑有促進黃金金露華植株生長之效果，且以夏季使用較為有效。而以泥炭苔混合介質種植黃金金露華時，未因添加保水劑而有促進植株生長之效果，尤以冬季種植時，添加保水劑處理之植株生長表現反而略遜於對照組。綜合上述，植物於適當生長環境下生長較快、需水量也較大，於該種環境下以介質混合添加保水劑對植株抗乾旱逆境較為有效。

Reducing water usage in order to make full use of water resources is an important issue for growers today. Bedding plants are usually grown in small containers that are easily susceptible to water stress. Hydrogel amendments had been reported to be effective on reducing irrigation requirements, increasing transplanting survival rate, and improving plant growth and flowering. This study aimed to investigate the effects of hydrogel amendments on plant growth and water use of bedding plants. Three hydrogels, Alcosorb® (AS), TerraCottem® (TC), and Taisap DC-386A (TS), were incorporated in the growing media of Lantana camara grown under water deficit environment. Substrate incorporated with these three hydrogels had increased water content and electrical conductivity, and reduced hardness. Hydrogel treatments could reduce drought stress of plants grown under water deficit environment. Especially sandy loam treated with 12 g•L-1 AS, 6 or 12 g•L-1 TS had better plant growth. Peat based substrate [2 peatmoss: 1 perlite: 1 vermiculite (by volume)] treated with 12 g•L-1 AS had better plant growth. Torenia fournieri ‘Clown Burgundy’ plants grown with peat based substrate incorporated with 12 g•L-1 TC and 6 g•L-1 AS had better plant growth under water deficit condition. In addition, Alcosorb® at rate of 0, 3, 6, 9, or 12 g•L-1 was tested for the production of Torenia fournieri ‘Clown Burgundy’ in 9-cm pot with peat based medium. Overall plant growth and drought tolerance was better when 3 g•L-1 AS was incorporated in the substrate. Impatiens wallerana ‘Accent’, Begonia semperflorens-cultorum ‘Super Olympia Pink’, and Viola cornuta were grown in peat based substrate mixed with 3 g•L-1 AS (Mix-AS) or with 3 g•L-1 AS placed under substrate (Bottom-AS) under day/night temperatures of 30/25 and 20/15 oC. Hydrogel treatments had no effect on improving drought tolerance of Impatiens wallerana ‘Accent’. Whereas Mix-AS treatment had better plant growth of Begonia semperflorens-cultorum ‘Super Olympia Pink’ and Viola cornuta under 20/15 oC. Duranta repens ‘Golden Leaves’ was grown with sandy loam and peat based substrate both mixed with 9 g•L-1 AS. Hydrogel treatment resulted in better plant growth when plants were grown with sandy loam substrate, especially during summer. However, no significant effect were recorded when plants were grown with peat based substrate. Moreover, plant growth of hydrogel treatment was reduced compared to control plants. Consequently, growth rate and water requirement were greater when plants were grown under suitable conditions, therefore hydrogel treatments had significant effect on improving drought tolerance of plants.