養液循環式Ebb & Flowによるミニチュアローズ'Nakashima91'の鉢物の生育と植物体吸収窒素量の季節的変化(土壌管理・施肥・灌水)  [in Japanese] Seasonal Changes of Growth and Nitrogen Up-take in Potted Miniature Rose 'Nakashima91' Cultivated by Recirculating Ebb & Flow System(Soil Management, Fertilization & Irrigation)  [in Japanese]

循環式Ebb & Flow方式でのミニバラ鉢物生産において, 栽培期間の気温と生育との関係および植物体の窒素吸収特性について調査した.栽培は2001年9月21日〜1月15日(秋栽培), 2002年2月5日〜5月13日(春栽培), 2002年6月17日〜8月19日(夏栽培)に行った.いずれの栽培区も栽培終了時の日積算温度は1700〜1900℃とほぼ同じであり, 植物体乾燥重と日積算温度との間には有意な相関関係が認められた.乾燥重増加量と植物体吸収窒素量とは一次回帰式で表現でき, ミニバラは栽培時期および生育ステージにかかわらず生長量に応じて常に一定量の窒素が吸収されていた.植物体吸収窒素の総量は, 各栽培区とも80〜95mgの範囲で大きな差は認められなかったが, 施与窒素量は大きく異なり, 夏栽培区では130mgであったのに対して, 秋栽培区では180mg, 春栽培区では240mgと著しく多かった.各栽培区ごとの植物体窒素吸収効率は, 夏栽培区が68%と著しく高く, 次いで秋栽培区の41%, 春栽培区の34%の順であった.鉢内の土壌溶液内窒素量は, 秋栽培区および夏栽培区では期間を通じて1鉢当たり8mg前後および4〜5mg前後で一定していた.これに対して春栽培区では栽培初期から1鉢当たり12mgと高く, その後15mg以上に上昇し, 鉢内土壌への窒素集積が推定できた.

Relations between seasonal growth and nitrogen uptake of potted miniature rose 'Nakashima91' cultivated in a recirculating Ebb & Flow system were investigated. The potted roses were cultivated in autumn; 2001/9/21-2002/1/15, spring; 2002/2/5-2002/5/13, and summer; 2002/6/17-2002/8/19. The cumulative temperatures from the start to end of cultivation were 1700-1900℃, irrespective of cultivation seasons. There was a significant correlation between the dry plant weight and the cumulative temperatures. A linear relation was found between increased dry weight and nitrogen uptake. This result indicates that the miniature roses absorbed nitrogen in proportion to the increase in dry weight. At the end of cultivation, the total nitrogen concentration in plants per pot was 80-95mg, regardless of the cultivation season. However, the amounts of nitrogen supplied to a pot during summer, autumn and spring cultivation terms were 130, 180 and 240mg respectively. The nitrogen absorption efficiency during summer cultivation was higher than other that during terms, and those in summer, autumn and spring were 68%, 41% and 34% respectively. The nitrogen concentration in soil solution in summer and autumn cultivation was fixed at 8 and 4-5mg per pot respectively. However, that in spring cultivation was already higher than that in summer and autumn at the start of cultivation and was 12mg per pot. Then the nitrogen concentration in soil solution rose beyond 15mg per pot at the end of cultivation. This increase in nitrogen concentration in spring soil solution indicates that nitrogen had accumulated in the soil.