Abstract: By quantitatively analysing, the results showed that tiller densities of ryegrass population had gone down by 37.0%,and leaf densities of white clover population had gone down by 54.2% during the last ten days of May to the first ten days of June.Ryegrass population occupied a dominant place in the mixture pasture.At two growth stages on May and June,yields of ryegrass population were a exponential function decrease along with increase of leaf densities of white clover population,yields of white clover population were a linear function decrease along with increase of yieids of ryegrass population.The negative effects were getting larger between the densities and the yields,but was more and less alike level between the yields of two populations of ryegrass and white clover along with progress of growth season.Yield of mixture pasture had nearly been the largest up to the first ten days of June.

Key words: Lolium perenne, Tirfolium repens, Growth and decline of density, Interspecific competition, Mixture

摘要： 定量分析的结果表明,从5月下旬至6月上旬,黑麦草种群蘖密度减少了37.0%,白三叶种群叶密度减少了54.2%。黑麦草种群在混播草地中占有优势地位。在两个生长时期黑麦草种群生产量随着白三叶种群叶密度增加均呈指数函数下降,白三叶种群生产量随着黑麦草种群生产量增加均呈直线下降。随着生长季的进程,两个种群在密度与生产量之间的负向效应呈增强趋势,但两个种群在生产量之间的负向效应却基本保持相同水平。至6月上旬,混播草地已接近于最大生产量。

关键词: 黑麦草, 白三叶, 密度消长, 种间竞争, 混播草地