閉鎖型養液栽培用に開発された培養液組成がトマトの成分吸収濃度に及ぼす影響(栽培管理・作型)  [in Japanese] Effect of Composition of an Improved Nutrient Solution for a Closed Hydroponic System on Nutrient Absorption by Tomatoes(Corp Production & Cropping Type)  [in Japanese]

培養液組成に大塚A処方区よりK濃度を高めNH_4-N,Ca,Mg,SO_4濃度を低めた改良処方区(NO_3-N:NH_4-N:P:K:Ca:Mg:SO_4=7.0:0.2:2.1:5.6:2.9:1.0:1.1me・L^<-1>)を供試し,かけ流し方式で給液および排液の量ならびに濃度,培地内溶液濃度,トマトの生育および収量を調査した.茎径は第7花房から上位において改良処方区で有意に太く,収量ならびに可販果率の平均値が大きかった.改良処方区の培地内溶液のNO_3-N,Ca,Mg,SO_4濃度は大塚A処方区より低く推移した.培地内溶液および排液のECは改良処方区で低かった.成分吸収速度はPでは差がなかったが,Kでは全期間,NO_3-N,Ca,Mg,SO_4では収穫開始期から摘心期頃まで改良処方区で高い傾向にあった.改良処方区のみかけの成分吸収濃度(n/w)は各成分ともほぼ一定のレベルで推移し,(n/w)/培養液濃度比は1.0〜1.2となった.閉鎖型養液栽培用に開発された培養液組成をかけ流し方式で検討したことにより以上のことが明らかとなり,改良処方区の組成,濃度はトマトの養分吸収とほぼ一致することが示唆された.

Tomatoes were grown in a greenhouse using a hydroponic system with an improved nutrient solution (NO_3-N : NH_4-N : P : K : Ca : Mg : SO_4 = 7.0 : 0.2 : 2.1 : 5.6 : 2.9 : 1.0 : 1.1 me ・ L^<-1>), which has higher K and lower NH_4-N, Ca, Mg and SO_4 levels than the Ootsuka-A formula (control). The study investigated the effects of the concentration of the solution within the medium and the volume and concentration of the exhaust solution, on the growth and yield of the tomatoes. Stem diameter at the seventh cluster and above were significantly larger and the yield and ratio of marketable fruits were higher in the improved nutrient solution plot. Fluctuations of NO_3-N, Ca, Mg and SO_4 levels in the solutions within the medium and in the exhaust was smaller with the improved nutrient solution than with the control. EC also was lower with the improved nutrient solution. There was no difference in P uptake, whereas uptake of K was higher with the improved nutrient solution during the entire season, and from the begining of harvest to pinching for NO_3-N, Ca, Mg and SO_4. Changes in the ratio of nutrient absorption per water consumption (n/w) were limited and the ratio of n/w to nutrient concentration was 1.0 to 1.2. It was shown that the formation and concentration of the improved nutrient solution matched the uptake ratio of the tomato plant within the conditions of the experiment.