补播羊草和黄花苜蓿对退化草甸植物群落特征的影响

呼伦贝尔草原区是我国北方重要的生态屏障，近年来不合理的利用方式导致该地区退化草地面积不断扩大，为了探究牧草补播时间及补播比例对呼伦贝尔退化草甸草原植物群落特征的影响，为该地区退化草地修复提供依据。本研究以羊草（Leymus chinensis（Trin.） Tzvel.）和黄花苜蓿（Medicago falcata L.）为试验材料，采用双因素随机区组试验设计，通过测定幼苗数、高度、生物量等群落指标，并综合评价补播效果，结果表明：夏播羊草和黄花苜蓿幼苗数量显著高于春播和秋播（P<0.05），夏播和秋播植物群落总生物量呈增加趋势，春播则呈减少趋势；补播措施提高了退化草地植物群落Shannon-Weiner指数、Simpson指数和Pielou指数，豆科和禾本科植物重要值呈增加趋势，其他科植物呈下降趋势。呼伦贝尔地区夏季补播羊草和黄花苜蓿以1∶3补播效果较好，而春播由于恢复时间短，需进一步观察。

Effects of Reseeding Leymus Chinensis(Trin.)Tzvel.and Medicago Falcata L.on Plant Community Characteristics of Degraded Meadow Steppe

The Hulunbuir grassland is an important ecological barrier in northern China, in recent years, unreasonable utilization has led to the continuous expansion of degraded grassland in this area. This study was aimed to investigate the effects of reseeding time and plant species ratio on the degraded meadow steppe of Hulunbuir, and provide basis for the restoration of degraded grassland. This study selected a two-factor randomized block design, Leymus chinensis (Trin.)Tzvel. and Medicago falcata L. were used as experimental materials, by measuring the number of seedlings, height, biomass and comprehensively evaluating the effect of reseeding. The results showed that reseeding Leymus chinensis and Medicago falcata in the summer obtained the highest seedlings compared to spring and autumn reseeding (P<0.05), the total biomass of summer and autumn reseeding exhibited an increasing trend, while spring reseeding decreased;reseeding increased the Shannon-Weiner index, Simpson index and Pielou index, the important values of leguminous and gramineous species showed an increasing trend, while forbs decreased. Reseeding effect was the best in summer reseeding Leymus chinensis:Medicago falcata 1:3, spring reseeding needs further observation due to the short restoration term.