蔬菜園土壤有效態氮測定研究

Abstract

本試驗擬研發適宜蔬菜園之土壤有效態氮速測方法，以診斷及推薦蔬菜之合理 氮肥施用量，減少環境污染。於溫室進行盆栽試驗及於實驗室內以孵育淋冼及化學萃取法探討土壤有效態氮之合宜評估方法。結果如下：化學萃取法中10%氯化鉀 溶液萃取法、熱2M氯化鉀溶液萃取法及熱 水萃取法所得之氮素量與孵育淋洗法之氮素量間均有顯著正相關。盆栽蔬菜收量及氮素吸收量與孵育淋洗法、熱2M氯化鉀溶液萃取法及熱水萃取法所得之氮素量呈顯著正相關，以10%氯化鉀萃取法所得及熱2M氯化鉀溶液萃取法之氮素量分別在94-163 mg/kg (平均爲124 mg/kg)及163-203 mg/kg (平均爲 181 mg/kg)之範圍時，無氮處理之產量百分率已達100%。進一步試驗結果也顯示EC測値與上壤中之硝酸態氮含量呈極顯著之直線正相關。 Methods of quick test of soil available N are accessed and developed in this project to enable soil diagnosis and fertilization recommendation for rational use of N fertilizer in vegetable fields and reduced impact on environment. Incubation leaching and chemical extraction methods are investigated in laboratory. Moreover pot experiment is conducted in greenhouse. Available N contents detected by chemical extraction methods, including 10% KC1, hot 2 M KCK and hot water, are all positively and significantly correlated with that by incubation leaching. Yield of pot culture and N uptake of vegetable are positively related with N contents detected by hot 2 M KC1, and hot water extraction. Percentage yield of non-fertilizer plot reached 100%, when N content detected by 10% KC1 or hot 2 M KC1 solution extraction method were fell in the range of 94-163 mg/kg(mean - 124 mg/kg) and 163-203 mg/kg (mean = 181 mg/kg) respectively. EC value had significantly linearpositive relationship with nitrate nitrogen content.