核桃-苜蓿-鸡治理模式对荒岗植物多样性的影响

为进一步完善核桃一苜蓿一鸡的荒岗治理模式，对该模式下荒岗植物多样性的变化进行了研究。结果表明：治理模式建立后，随运行年限的增加，在前4a林木郁闭度增长速度较快，第9年达到最高；单位面积林木保有量非常稳定，为700株／hm^2；核桃树高与冠幅前4a增长较快，以后基本稳定不变，保持在450cm左右；植物物种丰富度在运行期间呈现先增加后降低的趋势；植物多样性随着运行年限的增加而增加，4a后随着林木郁闭度的增大多样性降低，当郁闭度接近0．8时物种多样性和丰富度均较高。

Effects of walnut-clover-chicken governance mode on desolate hill vegetation diversity

In order to make the lonely hill governance mode of walnut-clover-chicken more effect,the changing of lonely hill vegetation diversity was studied.The results showed that: after established the governance mode,the canopy density was growing rapidly in the last four years with increasing of running years,and the canopy density achieved the highest in the ninth year.Trees possession quantity was very stable per unit area,which was 700 stocks/hm2.Trees height and crown width was growing rapidly in the previous...