不同频次刈割对内蒙古羊草草原群落能量固定与分配规律的影响

对内蒙古羊草草原在不同频次刈割影响下群落能量固定与分配规律的研究结果显示,群落地上能量现存量与刈割频次呈显著负相关关系,地下0～30 cm根系的能量现存量具有基本相似的变化趋势,区别在于17年内刈割3次的处理明显高于未割对照处理.群落总能量现存量的变化趋势与地下部分的变化完全一致.羊草草原地上部分的太阳能转化效率随刈割频次的增加逐渐下降,在未割对照群落中为0.257%, 而1年割2次群落仅为未割对照群落的37%.群落地上部分的能量含量也随刈割频次的增加呈线性下降趋势,地下部分能量含量则没有规律性的变化.在连年刈割影响下,群落能量向根系的分配比例增加,0～10 cm根系所蓄存能量在地下0～30 cm根系中所占比例也有增加趋势.但这种变化与刈割频次没有线性关系.

The effects of different frequency mowing on energy fixation and allocation of Leymus chinensis steppe community in Xilinguole, Nei Monggol

Based on the field experiment of mowing treatments with different frequency for 17 years, the changes of energy fixation and allocation of community in Leymus chinensis steppe of Nei Monggol were studied. The results showed that there was significant negative correlation between the aboveground energy standing crops of community and mowing frequency. Variation of underground energy standing crops with mowing frequency basically resembled to that of aboveground. The difference between them was that the value for the community with 3 mowing times in 17 years was obviously higher than that of unmowed. Variation of total community energy was similar to that of underground. The energy transforming efficiency gradually declined with mowing frequency. The value for unmowed community was 0.257%, but the value for the treatments with twice mowing in one year was only 37% of unmowed. The energy content of aboveground parts of community declined linearly (along) with increasing mowing frequency. That of underground did not show regular change. There was a (tendency) that the proportion of root energy accounting for whole community energy and that of 0-10 cm layers accounting for 0-30 cm layers increased under successive mowing, but there was not linearity correlation between the variations and mowing frequency.