不同沙丘类型对柠条林春尺蠖发生的影响

为了明确不同沙丘类型对春尺蠖在柠条林发生的影响,在腾格里沙漠东南缘地区,选择固定沙丘、半固定沙丘和半流动沙丘3种生境,研究了春尺蠖在3种生境柠条上的发生情况。结果表明:3种沙丘柠条上春尺蠖的发生存在显著差异,半固定沙丘春尺蠖发生最为严重,其后依次为固定沙丘和半流动沙丘,3类生境中春尺蠖的平均虫口密度分别为147.00、28.67、0.37只/株,被害株率分别为99.67%、64.67%、1.33%。通过对春尺蠖发生情况和环境因子(土壤物理化学性质和植被参数)进行相关性分析得出:柠条被害株率和虫口密度与土壤粉粒含量、土壤生物结皮盖度和柠条密度呈显著负相关关系(P﹤0.05),与土壤沙粒含量、柠条冠幅、柠条株高和土壤含水量呈极显著正相关关系(P﹤0.01)。沙漠区春尺蠖的发生与土壤表面的稳定性、土壤深层水分含量有关。

Effects of Different Types of Dunes on Occurrence of Apocheima cinerarius in Caragana korshinski Shrubs

To illustrate the influence of different types of dunes on occurrence of Apocheima cinerarius in Caragana korshinski shrubs,the fixed sand,semi-fixed sand and semi-mobile sand were selected as re-search plots to explore the effect of different habitat on occurrence of A. cinerarius in C. korshinski shrubs in southeast region of Tengger desert. The results showed that the average population densities of A. ciner-arius in three habitats were 147. 00,28. 67 and 0. 37 individuals per plant,respectively. The victimization rates of C. korshinski were 99. 67%,64. 67% and 1. 33%,respectively. The occurrence of A. cinerarius was significantly different in the three types of sand,which was most serious in semi-fixed sand,followed by fixed sand and semi-mobile sand. Correlation analysis of A. cinerarius occurrence and environmental factors ( soil physical and chemical properties,vegetation parameters) showed that the damaged rate and insect population density negatively correlated with soil powder content,cover of soil biological crust and C. korshinski density(P<0. 05),and positively correlated with soil silt content,soil water content,and C. korshinski canopy and height(P<0. 01). The occurrence of A. cinerarius in C. korshinski shrubs was relat-ed with stability of soil surface and soil water content of deep layer.