Abstract: The grassland ecosystem has been damaged seriously and the deterioration area is keeping expanding due to the unreasonable utilization.In order to explore the optimal utilization of Leymus chinensis(Trin.) Tzvel.grassland,an experiment was carried out in 2005 and 2006 to investigate the seasonal dynamics of aboveground biomass and growth rate of L. chinensis grassland.The results show that there was a seasonal dynamic increase from slow to fast in aboveground biomass of the grassland community and L. chinensis population with peak values achieved around 10 August.L. chinensis population had a higher Absolute growth rate and relative growth rate at the initial growth stage.Dynamics of aboveground biomass of grassland community and L. chinensis population accorded with the logistic equation model.In 2005,the biomass protective index of grassland community and L. chinensis population was 85.20 and 75.62 g·m^-2,respectively.In 2006,the biomass protective index of grassland community and L. chinensis population was 126.94 and 103.56 g·m^-2,respectively.

Key words: Leymus chinensis grassland, Aboveground biomass, Growth rate, Logistic model

摘要： 为探讨天然羊草(Leymus chinensis(Trin.)Tzvel.)草地合理利用途径,对坝上羊草草地2005年和2006年地上生物量动态进行了观测记录。结果表明:草地群落和羊草种群生长前期地上生物量呈由慢到快增长的季节性变化,且均在8月10日左右达到最大值;羊草绝对生长速率和相对生长速率的增长期都集中在生长季初期;群落和羊草地上生物量增长动态均符合Logistic生长曲线,2005年群落地上生物量保护指标为85.20 g/m²,羊草地上生物量保护指标为75.62 g/m²;2006年群落地上生物量保护指标为126.94 g/m²,羊草地上生物量保护指标为103.56 g/m²。

关键词: 羊草草地, 地上生物量, 生长速率, Logistic生长曲线