祁连山东段高寒灌丛土壤养分空间分布特征

Spatial distribution characteristics of soil nutrients in different alpine shrubs in the eastern Qilian Mountains

【目的】探讨祁连山东段高寒灌丛的土壤养分空间分布以及“肥岛”效应,验证高寒灌丛“肥岛”发育的物种效应。【方法】选取了山生柳(Salix oritrepha)、硬叶柳(Salix sclerophylla)和绣线菊(Spiraea salicifolia)3种高寒灌丛,对灌丛水平方向不同部位以及不同土层土壤养分含量进行分析,研究了不同高寒灌丛土壤养分的空间分布规律。【结果】SOC分布特征:3种灌丛SOC含量在水平方向上均呈现出由根部经冠下向灌丛间地处逐渐递减的趋势;垂直分布来看,3种灌丛SOC含量总体呈现出随着深度的增加逐渐减小的趋势,并且不同种类灌丛作用深度也不同。TN分布特征:在水平方向上,3种灌丛TN含量在表层(0~20 cm)呈现出根部高于灌丛间地的现象;在土壤的垂直剖面,3种灌丛土壤TN含量的规律同SOC的变化趋势一致。TP分布特征:除山生柳灌丛在水平方向上呈现出由内向外逐渐增加的趋势外,硬叶柳以及绣线菊无明显规律;山生柳灌丛土壤TP含量在垂直方向上随着深度的增加呈现出逐渐递减的趋势,硬叶柳和绣线菊各土层之间TP含量变化并不大。富集率总体表现为山生柳>绣线菊>硬叶柳。【结论】研究区高寒灌丛“肥岛”的发育具有物种效应,山生柳灌丛“肥岛”更深更广,灌丛土壤对于养分的聚集高于其他灌丛。

【Objective】To investigate the spatial distribution of soil nutrients and‘fertilizer island’effect of alpine shrubs in the eastern part of the Qilian Mountains,and to verify the species effect of the‘fertilizer island’development of alpine shrubs【.Method】Three species of alpine shrubs,Salix oritrepha,Salix sclerophylla and Spiraea salicifolia,were selected to analyze the soil nutrient content in different positions and different soil layers in the horizontal direction of the shrub and to study the spatial distribution law of soil nutrients in different alpine shrubs【.Result】SOC distribution characteristics:the SOC content of the three shrubs gradually decreased from the root to the inter-shrub area in the horizontal direction;in terms of vertical distribution,the SOC content of the three shrubs showed a trend of gradually decreasing with the increasing depth,and the effect depth of different shrubs was also different.TN distribution characteristics:in the horizontal direction,the TN content of the three shrubs in the surface layer(0~20 cm)is higher than that in the soil between shrubs;in the vertical profile of soil,the law of TN content in the three shrub soils is consistent with the change trend of SOC.TP distribution characteristics:in the horizontal direction,except that Salix oritrepha shows a gradual increasing trend from the inside to the outside,there is no obvious law for Salix sclerophylla and Spiraea salicifolia;in the vertical direction,the TP content of Salix oritrepha shrub soil shows a gradual decreasing trend with the increase of depth,and the TP content did not change much between the soil layers of Salix sclerophylla and Spiraea salicifolia.The overall enrichment rate was as follows:Salix oritrepha>Spiraea salicifolia>Salix sclerophylla【.Conclusion】The development of‘fertile islands’of alpine shrubs in the study area has a species effect,the"fertile islands"of Salix oritrepha is deeper and wider,and the accumulation of nutrients in the shrub soil is higher than that of other shrubs.