トマト水耕栽培における硝酸態窒素およびリンの定量施与が養分吸収および果実生産に及ぼす影響(栽培管理・作型)  [in Japanese] Effect of the Limited Supply of Nitrate and Phosphate on Nutrient Uptake and Fruit Production of Tomato (Lycopersicon esculentum Mill) in Hydroponic Culture(Crop Production & Cropping Type)  [in Japanese]

2週間間隔で第1花房開花期から果実収穫終了までの期間,一定量の硝酸態窒素とリンを施与する培養液管理法(定量施与)で,湛液式水耕装置を用いトマト(品種'桃太郎')を水耕栽培した.栽植密度3.6本/m^2,収穫段数は4段で,7月に収穫を終える春夏作と1月に収穫を終える秋冬作を行った.春夏作では硝酸態窒素を50me/株/週の割合で,リンを20me/株/週の割合で2週間ごとに施与した区で両養分がほとんど吸収され,3.5kg/株の果実生産量が得られた.尻腐れ果,乱形果,空洞果の発生も少なかった.一方,秋冬作では,硝酸態窒素の施与量の違いに関わらず,栽培期間を通じ平均して35me/株/週の割合で,リンは約16me/株/週の割合で吸収され,2.5kg/株の果実生産量が得られた.尻腐れ果,乱形果の発生は少なかったが空洞果の発生率が高かった.果実生産量,果実品質および養分吸収速度から判断して,培養液を更新せずに一定量の硝酸態窒素とリンを2週間間隔で施与する定量施与管理法でトマトを水耕栽培することが可能であることが明らかになった.

Tomato(Lycopersicon esculentum Mill. cv Momotaro) were cultured with a limited supply of nitrate and phosphate in DFT culture system. Experiments were carried out during the spring to summer season and autumn to winter season in a greenhouse. During the spring to summer season almost all of the nitrate and phosphate supplied at a rate of 50 me ・ plant^<-1> ・ week^<-1> and 20 me ・ plant^<-1> ・ week^<-1>, respectively was absorbed. Fruit weight was 3.5 kg ・ plant^<-1>. Occurrences of blossom end rot, malformed and puffy were limited. During the autumn to winter season, nitrate was absorbed at a rate of 35 me ・ plant^<-1> ・ week^<-1> regardless of the nitrate amount supplied, and phosphate was absorbed at a rate of 16 me ・ plant^<-1> ・ week^<-1>. Fruit weight was 2.5 kg ・ plant^<-1>. About 25% of fruit were puffy. From this experiment, it was shown that tomatoes can be cultured with a limited supply of nitrate and phosphate.