不同放牧时期绵羊啃食对冷蒿和羊草生长高度的影响

利用野外实验所获得的数据,进行差异显著性分析、多重比较,研究不同时期(5～8月)放牧啃食对冷蒿和羊草生长的影响(放牧前后枝条高度的变化),结果表明:不同时期放牧对冷蒿和羊草都具有显著的影响(啃食高度cm).在5～7月间,对冷蒿的影响程度基本上呈现降低的趋势,而在8月有所增加.在6～7月,放牧对冷蒿的影响极小,为冷蒿的再生提供了有利的时间保证.在5～8月,放牧对羊草的影响基本上呈递减的趋势.不同时期放牧对冷蒿和羊草的影响大致成互补的关系.不同时期放牧对冷蒿影响的波动与羊草相比较为平缓,而且不同时期放牧对冷蒿的影响比羊草低.

The Effect of Nibbling Sheep on the Growth Height of Leymus chinensis and Artemisia frigida in Different Grazing Periods

The effect of grazing on the height of Leymus chinensis and Artemisia frigida was researched from May to August by means of T-test and Multi-comparison.The results showed that L.chinensis and A.frigida were affected significantly by grazing intensity in different periods.There emerged a decreasing tendency of grazing effects on A.frigida from May to June,but a increasing tendency in August.The effect of grazing on A.frigida was little from June to July,which provided a favorable situation for regrowth of A.frigida.From May to August,the effect of grazing on L.chinensis was in a falling trend.The effect of grazing on L.chinensis and A.frigida was complementary in different periods.As compared with the effect of grazing on L.chinensis,the fluctuation of grazing effect on A.frigida was relatively stable,and thus the A.frigida was not signifantly influenced.