對日本普通蕎麥、日本韃靼種蕎麥與中國韃靼種蕎麥施以每公頃0（對照）、30、60、120、180公斤五種氮肥劑量，以瞭解其對生長之影響，裨供作蕎麥用於生產蕎麥草茶用之施肥基準參考。三種蕎麥對氮肥施用劑量之反應略有差異，無法用複因子變方分析解釋。個別檢討氮肥施用量時，以植株生長量，尤其是乾重為主時，日本普通蕎麥與日本韃靼種蕎麥之適宜施用量在100-120公斤/公頃，而中國韃靼種蕎麥則在140-160公斤/公頃之間。蕎麥植株最主要機能成分為芸香苷，其含量與氮肥施用量，呈現二次線性正相關，即施肥量最高與最低時，有最高含量，三種蕎麥之芸香苷含量最低時，理論上分施氮肥量分別為90、119、101公斤/公頃。
In order to understand the relationship between nitrogen dosage and buckwheat growth, five nitrogen fertilizer dosages, which were 0, 30, 60, 120, 180 Kg.ha^(-1), were applied to three kinds of buckwheat and they were Japanese common buckwheat, Japanese tartary buckwheat and Chinese tartary buckwheat. This research could be used as a reference for the application of buckwheat fertilizer dosages. During individual analyses of nitrogen fertilizer dosages according to biomass yield, the optimum nitrogen dosage of Japanese common buckwheat and tartary buckwheat was between 100-120 Kg.ha^(-1), while the optimum nitrogen dosage of Chinese tartary buckwheat was 140-160 Kg.ha^(-1). The main phytochemical of buckwheat is Rutin and its content was significantly correlated to nitrogen dosages. The best dosage for Rutin content of Japanese common buckwheat, Japanese tartary buckwheat and Chinese tartary buckwheat was 90, 119, 101 Kg.ha^(-1), respectively.
