混播草地不同种群再生性的研究

Regrowth of different plant populations in mixed pasture.

在不同刈割频率和时间尺度下 ,对混播草地多年生黑麦草 (Lolium perenne)分蘖数和叶片生长、白三叶 (Trifoliumrepens)分枝数和匍匐茎生长及不同种群年产量和组分进行了连续 3年的监测研究 .结果表明 ,刈割能刺激黑麦草叶片、白三叶匍匐茎生长和分枝数发生 ,保持混播草地黑麦草和白三叶的适宜比和稳定共存 ,提高草地年生产力 ,但不同刈割频率和刈割时间对其影响差异不显著 (P >0 .0 5 ) .黑麦草叶片生长对 6月刈割效果比 8月明显 ,而白三叶匍匐茎生长则与之相反 ,黑麦草产量主要取决于叶片生长 ,白三叶产量主要取决于匍匐茎分枝数 .刈割的黑麦草、白三叶产量组分比分别为 5 0 %、15 % ,比试验前约低 10 %、5 % ,而CK为 39%、6 % .

The number of tillers and leaf regrowth of perennial ryegrass ( Lolium perenne ) and that of branches and stolon growth of white clover ( Trifolium repens ) in mixed ryegrass/white clover pastures under different cutting frequency were monitored from 1998 to 2000,and the herbage yields and the proportion of each component in total yields were also determined. The results showed that cutting could stimulate perennial ryegrass leaf regrowth and white clover branching, maintain proper proportions of perennial ryegrass and white clover in the mixed pasture, and create the environments for the coexistence of the two species. Therefore, the total annual dry matter yields of the pasture was increased. However, cutting frequency had no significant effects on herbage yields and vegetative composition (P>0.05). More leaf regrowth of perennial ryegrass was found in theplots cut in June than in August, whereas white clover exhibited an inverse trend. The herbage yield of perennial ryegrass depended on its leaf regrowth , while the dry matter accumulation of white clover relied on its stolon branching numbers. During the period of three year experiment, the proportion of perennial ryegrass and white clover in total herbage yields obtained from the plots under cutting was 50% and 15%, respectively, approximately 10% or 5% lower than its initial value,while CK was 39% and 6% ,respectively.