三峡库区不同退耕地对多年生混播草地种群稳定性的影响

选择3种不同的退耕地，即前茬为水稻地、黄豆地和草皮地，进行混播人工草地建设。分析测定了6个组合、2个混播比例（3:7和5:5）在不同退耕地中的生长速度、总产量、组分产量及各组分比例。结果发现不同退耕地显著影响人工草地产量及组分变化。黄豆地产量显著高于水稻地和草皮地（p<0.01）。而草皮地豆科牧草产量又显著高于黄豆地和水稻地（p<0.01）。同时，不同组合的产草量及组分比例随着刈割时间的不同而不同。草皮地中各牧草第2次刈割产量平均较第1次提高430%。3种土壤中，除F组合3:7混播比例外，2个组合不同混播比例苇状羊茅与鸭茅的比值都是第2次小于第1次。

The Effect of Pre-crops on the Population Stability of Perennial Artificial Grassland in Three Gorges Regions

Three kinds of newly returned lands from three pre-crops were selected to establish mix-sowing artificial grassland in Three Gorges Region. The growth speed, grass yield, grass proportion and grass weight ratio of 6 grass combinations were determined to analyze the difference between different lands. The results showed that the grass production and grass proportion were significantly influenced by the soils (p<0.01). The grass yield in soybean land was significantly higher than that in rice land and turf land (p<0.01). While the legume grass yields was significantly higher in turf land than that in rice land and soybean land (p<0.01). And the grass production and proportions in different cutting times were changed differently in different lands. The average grass yield in soybean land in second cutting time was increased about 430%. Compared with the first cutting time, the proportion between Festuca arundinacea and Dactylis glomerata in two combinations and two proportions were decreased in second cutting time, except the combination F with 3:7 proportion.