Abstract: In order to understand the effect of row spacing and seeding rate on growth characteristics and yield of Poa pratensis L. Qinghai,and screen out the optimal row spacing and seeding rate for forage grass production and seed production，the split plot design was adopted in this study,and four main and secondary plots with different row spacing and seeding rate were set out respectively,and the changes of chlorophyll content,leaf nitrogen content and plant height during the growth season were monitored. The net photosynthetic rate,fresh forage yield,dry hay yield and seed yield at the maturity stage were measured,and seed examination and germination experiments were conducted to investigate the effects of row spacing and seeding rate on seed yield and seed quality. The results were as follows: the sowing under the row spacing 20 cm and the sowing rate 5 kg·hm^-2,the hay yield and seed yield of Poa pratensis were the highest,reaching 7 600 kg·hm^-2 and 1 366 kg·hm^-2in the second year after planting,respectively,along with the highest of average value of the membership function values of seed germination indexes. The row spacing mainly affects the seed yield by the weight of 1 000 grains,the number of spikes per acre and the number of seed per spike,and the contributions to the seed yield were ranked as the number of spikes per acre,the weight of 1,000 grains and the number of seed per spike orderly;the forage yield was affected by row spacing,sowing rate and their interaction. The content of chlorophyll and leaf nitrogen first increased and then decreased with prolonging of the growth period,and there was a significant correlation of the two with the photosynthetic rate;and the photosynthetic rate,transpiration rate and stomatal conductivity were significantly correlated to and significantly affected by sowing rate.

Key words: Row spacing, Sowing rate, Growth characteristics, Forage yield, Seed yield

摘要： 为明确行距和播种量对'青海'草地早熟禾(Poa pratensis L. Qinghai)生长特性和产量的影响，筛选出适宜其饲草生产和种子生产的最佳种植行距和播种量。本试验采用裂区设计，分别设置4个不同行距和播种量为主副区，分析整个生育期不同处理下叶绿素含量、叶氮含量和高度的变化；测定完熟期时各处理的净光合速率，鲜草产量、干草产量和种子产量，并进行考种和发芽试验，研究行距和播种量对牧草产量和种子产量及种子质量的影响。结果表明：过马营镇地区播种行距20 cm，播种量5 kg·hm^-2，牧草干重产量和种子产量最高，分别达到7 600 kg·hm^-2和1 366 kg·hm^-2，种子发芽指标的隶属函平均值综合排序也最高。行距影响植物生殖指标中的千粒重、亩穗数和穗粒数进而影响种子产量，种子产量贡献结果由大到小为亩穗数＞千粒重＞穗粒数；牧草产量受行距和播种量及二者交互作用的影响。叶绿素和叶氮含量随生育期推进呈先升高后降低趋势，且二者与净光合速率有显著的相关性；光合速率，蒸腾速率和气孔导度呈极显著相关且受播种量影响显著。

关键词: 行距, 播种量, 光合速率, 草产量, 种子产量