高寒地区禾草混播人工草地建植早期杂草群落动态变化研究

Study on the Succession of Weeds in Mixed Perennial Artificial Grassland in the Alpine Region

对高寒地区禾草混播草地第一至第四年的草地群落杂草进行了研究。发现:1.从一龄草地到四龄草地一年生杂草种类减少,杂草种类总数增加,且增加的杂草是多年生。一龄、二龄草地杂草种类相同,为一年生;三龄、四龄草地一年生杂草减少。2.从一龄草地到四龄草地组分种数量特征发生重大变化。一年生杂草在一龄时为优势种,第二年就退出优势地位,第三年开始多年生虽单种数量较少但种类增加,从而杂草在群落中的地位又发生变化或加强了发生变化的潜力。3.化学防除对第一、二年的草地群落结构和产量都有重大的影响;施肥抑制杂草侵入,利于维持草地稳定;放牧促进杂草侵入,使草地退化加速。4.覆盖播种防除杂草的效果变化较大;单播草地稳定性差,2、3、4组合混播草地杂草群落在三龄时差异不大,但草地产量依次递增。5.从一龄到四龄禾草混播草地杂草群落的变化出现了4个明显的时期:一年生杂草占优势时期、多年生目标禾草占优势时期、多年生杂草大量出现的时期和多年生杂草占优势时期。

The weed in mixed perennial artificial grassland in alpine region of Tianzhu was studied and the results indicated that: 1) The number of species of annual weeds decreases from the oneyearold grassland to the fouryearold, however, the species of perennial weeds greatly increases. The species of weeds in the firstyear and secondyear grassland is same and dominated by annual. Annual weeds in the thirdyear and forthyear grassland decreases. 2) The dominant weed species changes apparently from the firstyear to forthyear grassland. The annual weeds are dominant in the firstyear grassland and become subordinate after the secondyear. The perennial weeds significantly increases from the thirdyear. 3) The weeds can be decreased by herbicide and then the grass quantity is increased. The fertilizer can improve the quality and quantity of grasses and restrain the weeds; meanwhile, the effect of grazing on grassland is negative. 4. The effect of cover seeding with oat varies. 5. The development of population structure of grassland can be sorted into four stages from the firstyear to the forthyear.