Abstract: A study was conducted to determine the optimum N-fertilizer application rate for maximum seed yields of zoysiagrass stands from seeding and transplanting respectively, in Jiaozhou City, Shandong Province, from 2001 to 2003. The results indicated that in the third year after establishment, seed yields and yield components for both stands showed a similar response to N-fertilizer. Maximum fertile tiller numbers (3 342 and 2 941 heads·m·2 from stands seeded in rows and transplanted, respectively) and highest seed yields (844.50 and 874.65 kg·ha-1 from stands seeded in rows and transplanted, respectively) were reached at a fertilizer application rate of 20 and 10 kg N·ha-1 in autumn and spring (30 kg N·ha-1 in total). Further increase in N fertilizer application rate decreased the fertile tiller numbers and seed yields. The length of spikelet, spikelets per fertile tiller, seed numbers per head, seed setting percentage and 1000-seed weight increased with the application rate of N fertilizer. Compared with the stand seeded in rows, the 1000-seed weight and the length of spike from transplanted stand were higher. The optimal harvest time of Zoysiagrass in Jiaozhou City was about 36 days after anthesis, near June 15th, when the seed moisture content reached 26% -28%.

Key words: Zoysiagrass(Zoysia japonica), Nitrogen fertilizer, Seed yield, Yield component