Abstract: How initial plant density affecting the population dynamics and productivity is a key issue to determine the optimal sowing rate and to maintain pasture stability and productivity. This study was taken in glasshouse aiming to explore the self-thinning pattern and production of white clover,with 8 plant densities and 3 replicates in a randomized complete design. The results showed that self-thinning occurred in all the treatments,the higher plant density the higher death rate was;The final plant density positively responded to initial density but growing point density did not;Plant density had no significant effects on growing point density,aboveground biomass and total biomass;However,above and belowground biomass and total biomass significantly related to growing point density;Above ground biomass and total biomass followed the law of constant final-yield. The results suggested that plants like white clover,the intraspecific competition intensified as sowing rate increased. Growing point density maintains relatively stable in a wide range of sowing rate and is a major factor for productivity.

Key words: White clover, Biomass, Initial density, Growing point, Self-thinning

摘要： 开展牧草初始密度对种群动态和生产力影响的研究，对确定合理播种量、保障种群稳定性和生产力有重要意义。本试验在温室条件下，探索白三叶（Trifulium repens）不同初始密度对植株和生长点动态与生物量等种群特性的影响。结果表明，不同初始密度下植株都存在自疏现象，密度越高，个体死亡率越高，但是生长点数没有显著差异；植株密度对生长点数、地上生物量、总生物量等性状影响不显著，生长点数与地上生物量、地下生物量、总生物量等呈显著正相关；地上生物量、总生物量遵循产量恒定法则。这说明，具有根孽性的白三叶牧草，植株个体间竞争随播种密度的增加而加剧，生长点在较大播种范围内保持相对稳定的数量，是影响种群生物量的重要因子。

关键词: 白三叶, 生物量, 密度, 生长点, 自疏