Korean Lawn. Zoysia japonica Steud. is the type of a perennial warm-season turfgrass keeping green leaf color for 5 months from May to September in natural condition in Korea. This Studies were carried out to obtain the effects of N-P-K fertilization, regrowth capacity after mowing and chlorophyll contents on prolongation of the green leaf color period in Zoysia japonica Steud turfgrass areas. The results obtained are summarized as follows ; 1.The effects of nitrogen fertilizer application in Zoysia japonica Steud, turfgrass areas were affected on regrowth ability after mowing green color of leaf canopies and chlorophyll contents, respectively(P<.05) 2.A experimental plots which applied 51 g/m$^2$/10 weeks of N$_3$P$_1$K$_1$fertilizer, there were high significant effects on prolongation of the green leaf color period and the plots of phosphorus and potassium had additive effects. 3.Prolongation of the green leaf color period to the last of October was obviously possible by slow degrees in proportation to increment of the fertilizer. However, it is interpreted that more prolongation of the green period is impossible with N-P-K fertilization and irrigation treatments. unless the intermediate turfgrasses between $C_3$ and $C_4$plants must be found and bred.