福岡県農業総合試験場研究報告22(2003) pp 121 - 126
県内茶園における埋設型ECセンサーを利用した効率的施肥管理技術
第２報 埋設型ECセンサーを利用した窒素施用量及び窒素溶脱量の低減
堺田輝貴・江上修一・中村晋一郎・森山弘信・松田和也
（八女分場）
茶園において，埋設型ECセンサーを利用した施肥管理により，収量，品質を維持しつつ， 50kg/10aレベルまで窒素施用量を削減し，窒素溶脱量を低減できるかどうか検討した。
その結果，埋設型ECセンサーを利用して，土壌中無機態窒素量をリアルタイムに把握し，施肥時期や窒素施用量を調節することで，収量，品質を維持しつつ， 窒素施用量を50kg/10aレベルまで削減することができた。また，窒素施用量の削減に伴い，地下浸透水中の硝酸性窒素濃度は低下傾向を示し， 窒素溶脱量は対照区と比較して40%程度低減することができた。
[キ−ワ−ド：茶園，埋設型ECセンサー，窒素施用量，硝酸性窒素濃度，窒素溶脱量]
Technique of Efficiently Fertilizer Administration Using Buried EC Sensor in Tea Field at Fukuoka Prefecture. 2. Reduction of Nitrogen Application and Amount of Leached Nitrogen Using Buried EC Sensor. SAKAIDA Teruki, Sinichirou NAKAMURA, Hironobu MORIYAMA and Kazuya MATSUDA (Fukuoka Agricultural Research Center, Chikushino, Fukuoka 818-8549, Japan)Bull. Fukuoka Agric. Res. Cent., 22: 121 - 126(2003)
We investigated reduction of nitrogen application up to approximately 50kg per 10a and amount of Leached nitrogen, while maintaining yield and quality, by fertilizer administration using buried EC sensor in tea field. As a result of examination, nitrogen application was reduced up to approximately 50kg per 10a, while maintaining yield and quality, by real time grasping inorganic nitrogen in tea field using buried EC sensor. By the reduction of nitrogen application, concentration of nitrate nitrogen in permeated ground water was decreased, and amount of leached nitrogen was reduced by 40% as compared to control.
[Key words: tea field, buried EC sensor, nitrogen application, concentration of nitrate nitrogen, amount of leached nitrogen]