吉兰泰盐湖绿洲柽柳灌丛生长与沙堆形态特征的关系

Relationship between Tamarix chinensis shrub growth and sand pile morphology in Jilantai Salt Lake Oasis

【目的】探明吉兰泰盐湖绿洲防护林带同一建植年限柽柳灌丛形态大小与阻沙能力之间的关系,以确定制约沙堆形成的灌丛形态参数,为吉兰泰盐湖绿洲防护林带建设提供参考。【方法】在相同建植年限的柽柳防护林带设置100 m×100 m的样方,用钢卷尺测量柽柳灌丛高度、冠幅长度、冠幅宽度、沙堆高度、沙堆长度和宽度,计算灌丛个体指数(SSI);将样方内柽柳灌丛分为大型灌丛、中型灌丛和小型灌丛,通过3类灌丛形态指标与沙堆形态指标之间的Pearson相关性分析和回归分析,研究柽柳灌丛发育过程中沙堆形态的变化特征。【结果】(1)随着柽柳灌丛的生长,其沙堆长度、宽度、高度、底面积和体积逐渐增大,从小型灌丛到大型灌丛SSI平均增加了50.42,沙堆底面积为0.12~31.64 m^(2),柽柳灌丛发育过程中沙堆形态均呈类椭球型。(2)Pearson相关性分析显示,灌丛高度是制约大型柽柳灌丛沙堆宽度的主要参数(R=0.931),小型、中型灌丛沙堆形态主要受灌丛长度和宽度的制约,小型灌丛长度和宽度与沙堆长度和宽度拟合方程的相关系数(R^(2))≥0.63。(3)柽柳灌丛SSI与沙堆体积拟合方程的相关系数(R^(2))为0.71,SSI与沙堆底面积拟合方程的相关系数(R^(2))为0.78,随着植株的生长SSI增大,其积沙能力增强。【结论】冠幅长度和宽度是灌丛生长前期影响积沙效果与沙堆形态的主要因素,随着灌丛生长及SSI增大,灌丛高度成为沙堆形态的主要制约因素。

【Objective】This study investigated the relationship between shrub morphology of Tamarix chinensis and its sand-blocking ability in same planting years in Jilantai Salt Lake Oasis shelterbelt and determined the shrub morphology parameters restricting formation of sand piles to provide reference for sand control and environmental improvement.【Method】A quadrat of 100 m×100 m was set in T.chinensis shelterbelt,and plant height,crown width,sand pile height,sand pile length and width of T.chinensis shrubs were measured with a steel tape.The shrub individual index(SSI)was calculated and the T.chinensis shrubs in the quadrat were divided into large shrubs,medium shrubs and small shrubs.Through Pearson correlation analysis and regression analysis between shrub morphological indexes and sand pile morphological indexes,the changing characteristics of sand pile morphology during the development of T.chinensis shrubs were studied.【Result】(1)With the growth of T.chinensis shrubs,the length,width,height,bottom area and volume of sand piles increased gradually.The SSI of T.chinensis shrubs increased by 50.42 on average from small shrubs to large shrubs,and the bottom areas were 0.12―31.64 m^(2).The shape of sand piles during the development of T.chinensis shrubs was ellipsoidal.(2)Pearson correlation analysis showed that shrub plant height was the main parameter restricting the width of sand piles in large Tamarix chinensis shrubs(R=0.931).The morphology of small and medium shrub sand piles was mainly restricted by shrub length and width.The fitting equations of small shrub length and width with length and width of sand piles had coefficients of R^(2)≥0.63.(3)SSI and sand volume fitting equations had coefficients of R^(2)=0.71,and SSI and sand bottom area fitting equations had coefficients of R^(2)=0.78.With the growth of plants,the sediment accumulation ability increased along with the individual index of shrub(SSI).【Conclusion】Shrub size was the main factor affecting sand accumulation effect and sand pile morphology at the early stage of shrub growth.With the increase of shrub growth and individual index,plant height became the main constraint factor of sand pile morphology.