刈割对紫花苜蓿根系生长影响的初步分析

研究了不同刈割次数对紫花苜蓿根系发育能力的影响。结果表明：刈割抑制紫花苜蓿主根的纵向(垂直)生长，而促进其横向(直径)生长，并使紫花苜蓿侧根发生总数减少和垂直分布的总体格局向表层集中，随着刈割次数的增加，侧根集中分布在土壤表层的比例也增加；刈割使根系生物量和体积总量减少，并随着刈割次数的增加，这种减少趋势更加明显，同时在土壤中的垂直分布变浅。

Effect of cutting on root growth in lucerne

A experiment was conducted in Hexi corridor during 2001~2002 to study the effect of several cutting times on the development ability of root system in lucerne. The study showed that the cutting restrained the taproot growth toward depth but increased its diameter growth and this trend became enhanced with more cutting frequencies. The secondary roots decreased and their distribution pattern changed in soil due to the cutting, and the more the cutting frequency was, the more secondary roots distributed at the 0~10 cm depth interval. The cutting made the root volume and biomass decrease, and this decrease enhanced with more cutting times. This study suggested that more cutting frequencies were disadvantageous to sustainable utilization of lucerne pasture with unavailable fertilization.