不同建植期混播草地群落特征的年际动态

针对新疆昭苏山前平地草甸草原严重退化的问题，采用耕翻混播种植6种豆科和禾本科牧草的方式，研究不同种植年限混播草地的物种消长、群落特征和产量变化。结果表明，混播草地植物组成、群落结构与对照(天然草地)相比均发生了明显变化，栽培牧草种占据绝对优势，牧草地上生物量均显著高于对照（P<0.05）；除2008年外，最高生物量均在7月中旬，比天然草地提前15 d以上，最高地上生物量平均为2 500 g·m-2，是天然草地的2.54倍。随着种植年限的延长，草地原有牧草先后出现，致使群落物种丰富度、多样性、均匀度总体呈增加趋势；栽培牧草重要值总体呈下降趋势，其中禾本科牧草呈增加而豆科牧草呈下降趋势，草地生产力虽呈下降趋势但仍保持较高生产力。

Changes of community characteristics in the legume/grass pasture in different year after establishment

The experiment was conducted to measure the changes of species number, yield and community characteristics in the pasture where mixed with 6 species of gramineae or leguminosae and lied in the degraded meadow steppe of Zhaosu piedmont in Xinjiang, aiming to provide theoretical basis and practical experiences for the improvement of degraded rangelands and construction of artificial pastures. The results showed that the species composition and community structure changed fundamentally compared with the control. The planted species in the pasture occupied predominate position and its above ground biomass was significantly higher than that of the control (P<0.05). The maximum biomass (about 2 500 g·m-2) appeared in the middle of July with over 15 days ahead of natural grassland, and it was 2.54 times than the control. The original grasses appeared successively resulting in species richness, diversity and evenness increased collectively along with the extension of years, and the important value of plant pasture declined. There was decline trend for the species of legume, but the species of grasses increased. The productivity in the pasture showed the trend of declination, however it maintained much higher.