| 水耕レタスの養水分管理法に関する研究. Studies on the Feasible Management of Nutrient Solution in Hydroponically Grown Lettuce (Lactuca sativa L.). | |||||||||||||
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| 1.サラダナ'岡山'を培養液自動補給装置を備えたNFTで栽培し, 養水分吸収を測定した.2.循環培養液濃度を園試処方の1/4, 1/2濃度の2水準3区ずつ設け, さらに連日無機成分分析を行って培養液中のNO_3-N, PO_4-P, Kのそれぞれを初期設定濃度に維持するように, 補給培養液の濃度を制御した.3.1成分だけを目標濃度に維持するよう補給培養液の濃度を調節すると, 結果的に他の成分濃度は徐々に変化し, NO_3-Nは上昇, PO_4-P, Kについては低下する傾向にあった.4.サラダナの生育は処理区間に差がみられなかった.5.培養液濃度が極端に低下した時を除けば, いずれの成分の見かけの吸収濃度n/wとも, 処理区間で差がなく, 生育が進むにつれ, 徐々に上昇した.6.本試験で得られたサラダナの見かけの吸収濃度n/wから計算した, 補給培養液の組成として, NO_3-N: PO_4-P: Ca: Mg-12: 4: 8: 4: 2(me/l)が得られた.. The nutrient uptake of lettuce cultivar 'Okayama' was investigated in NFT system where an automatic solution supply unit was installed. The concentrations of supplied nutrient solution were controlled with the aid of daily chemical analysis, so as to maintain two initial concentrations of target mineral, such as NO_3-N, PO_4-P and K in each recirculating solution. When one target mineral in recirculating solution was maintained to the objective level, the other mineral concentration varied gradually from the initial concentration, showing slow increase in NO_3-N and slight decrease in PO_4-P, K. There was no significant difference in the growth of lettuce grown in two nutrient levels. The nutrient uptake concentration, n/w for each mineral showed almost same values in all regimes with were gradually increasing with plant growth. The nutrient balance for lettuce which calculated by n/w values in the present study were estimated to be NO_3-N: PO_4-P: K: Ca: Mg=12: 4: 8: 4: 2 (me/l) | |||||||||||||
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