施氮肥对播种和分栽结缕草种子产量及其构成因素的影响

 2001～2003年在山东省胶州市研究了施肥对不同建植方式(植株分栽、种子播种)结缕草种子产量及其产量构成的影响。结果表明，植株分栽和种子播种建植结缕草种子田，第3年可取得同样的种子生产效果；适量的施氮肥可提高结缕草单位面积生殖枝数，种子播种和分栽小区均施氮肥30 kg·ha-1 (秋季20 kg·ha-1 +春季10 kg·ha-1) 效果最好，其生殖枝数分别为3 343和2 941个/m2，随着施氮肥水平的提高，生殖枝数并未增加，反而降低；施氮肥能增加结缕草的穗长、小穗数/生殖枝、种子数/生殖枝、千粒重及结实率；适量施氮肥可提高结缕草种子产量，以播种和分栽小区施氮肥30 kg·ha-1（秋季20 kg·ha-1 +春季10 kg·ha-1）种子产量最高，分别达到844.50和874.65 kg·ha-1；分栽结缕草种子田生产的种子要比播种种子田的种子千粒重大，而且穗轴长。结缕草种子的适宜收获期为盛花期后第36天 (6月15日前后)，此时种子含水量为26%～28%。

Effects of Nitrogen Fertilizer on Zoysiagrass (Zoysia japonica Steud.) Seed Yields and Yield Components from Seeding and Transplanting

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%.