Hsin-Chen Lee Research Assistant Agronomy Chia-Yi Agricultural Expriement Station Taiwan Agricultural Research Institute Phone:886-5-2771341 Fax: 886-5-2773630 Email: Education M. S. (1988) in Department of Horticulture, National Taiwam University. M. S. (1992) in Department of Horticulture, National Taiwan University. Area of Research Interest Breeding and cultural practies of sweet potato Quality analysis of sweet potato Publication Journal paper 1.Lee, Hs-Ch.,Y. C Lai and Y. S. Chen. 1996. Effects of plant spacing and Nitrogen Fertilizations on the Leaf Tips Yield of a Leafy sweet potato. Jour. Agric.Res. China 45(3)¡G230-240. The leaf vegetable sweet potato local varietyOng Tsai(water spinach) were used to study the effects of three plant spacing(within row spacing20,25and 30 cm, between row spacing 40 cm) and three levels nitrogen (0,10 and 30 kg/ha) fertilizers on yield and yield components, such as tip bud weight, tip bud length, tip bud width, leaf number and leaf area. The experiments were conducted during May to August in 1994 and 1995 at Chaiyi Agriculture Experiment Station. In 1994, dense planting treatment increased yield at lst and 3rd harvest, but not at 2nd and 4th harvest. No significant differences were found on yield components among three plant spacing treatments except at 3rd harvest 30 cm spacing promoted tip bud number, tip bud weight and tip bud width. In 1995, the effects of plant spacing on yield and yield components were not significant exclude the highest tip bud length and width were recorded in 30 cm treatment at 4th harvest. Nitrogen fertilizers tended to increase yield. Application 30 kg/ha nitrogen fertilizer got the highest plot yield. Nitrogen fertilizers also facilitated the yield components except leaf number in 1995, but not in 1994.The different response on yield and plant development according to differ form cutting range to stolons between 1994 and 1995 were discussed in this repot. Generally,light cutting on the stolon length (stolon) in 1995 provides better marketable yield, lateral shoots and new roots. Heavy cutting on the stolon length(non-stolon)in 1994, however, caused poor yield because of aging lateral shoots. The phenomena were more significant as harvesting times increased.