三要素適量範圍估計在N 90 Kg／ha，P2O5 45Kg／ha，K2O 60－120 Kg／ha，六腳試驗地K2O需要量較高，可能與其土壤有效鉀較低有關。
NPK Requirement of Black Salsify
H. Y. Huang
This experiment was carried out at Liockiao (Chiayi Hsin) and Lunpei (Yunlin Hsin). Ten incomplete combinations of NPK rates were compared. Black salsify was sown in October 1997 and harvested in the following March; the growth period was 130 days. The growth characters of black salsify were mainly affected by the nitrogen nutrition. The root length, leaf length, leaf weight and root weight were all influenced by nitrogen rates; the lower the nitrogen rate; the lower the nitrogen rate, the shorter the root and the lower the root yields. Too much nitrogen application, however, resulted in an increase of fibrous roots or swelling of the main root, affecting its appearance.
Based on the results of the two experimental sites, it may be concluded that the optimum nutrient rates for black salsify are: N, 90 kg/ha; P2O5, 45 kg/ha; K2O, 60~120 kg/ha. The K2O rate required at Liockiao was higher than at Lunpei, probably of the lower soil available K2O in the former case.