定植時の養分レベルがスプレーギクの生育と切り花品質に及ぼす影響(土壌管理・施肥・潅水)  [in Japanese] Effects of Nutrient Level at Planting Time on Growth and Quality of Cut Flower in Spray Chrysanthemums(Soil Management, Fertilization & Irrigation)  [in Japanese]

スプレーギクのベンチ栽培において,定植時の養分レベルが生育と切り花品質に及ぼす影響を調査するとともに,土壌溶液の養分レベルを指標とした適正濃度範囲を明らかにした.総窒素施肥量(267mg/シュート)に対する基肥の割合を0%,25%,50%,75%,100%とした.基肥以外の肥料分については各区とも栽培期間を通じて等分し,摘心時から7日間隔で与えた.さらに和歌山県の慣行施肥方法に準じて施肥を行う慣行区(総窒素施肥量500mg/シュート)を設けた.初期生育は,25%区および50%区で最も旺盛となったが,75%区,100%区では高濃度障害を引き起こし,抑制された.一方,栽培中期以降の生育は基肥割合にかかわらず良好であり,切り花品質は0%〜100%区間ではほぼ同様で良好となった.しかし,慣行区では他の区よりも葉が大きく茎が太くなり,切り花品質は低下した.以上の結果から,スプレーギクの養分管理においては定植直後の培地中の養分レベルを適正濃度範囲内に維持することが重要であり,生育初期におけるその適正濃度範囲は土壌溶液の硝酸態窒素濃度で50〜300ppm程度であると考えられた.

Effects of the nutrient level at planting time on growth and quality of cut flower in spray chrysanthemums were investigated. An equal amount of fertilizer measuring approximately N 267 mg/shoot was applied to each plot with different basal fertilizer ratios of 0%, 25%, 50%, 75% and 100%, respectively. The residual nutrients divided into 10 equal dosages were applied every week. For reference, fertilizer was also applied according to the conventional recommended method (N 500 mg/shoot). Initial growth of plants in 25% and 50% plots was better than that in the other plots. Necrosis due to excessive fertilization was observed in the leaves of plants in the 75% and 100% plots. Regardless of the ratio of basal fertilizer to total application, the quality of cut flowers was good and marketable. The quality of cut flowers from the conventional plot was lower than that from other plots due to excessive growth of leaves and stems. It is desirable to maintain the initial nutrient levels at planting time in a range between 50 and 300 ppm nitrate using a soil solution in spray chrysanthemum production.