不同气候区灌丛沙堆形态及土壤养分积累特征

灌丛沙堆是干旱、半干旱区绿洲边缘常见景观类型，在绿洲风沙防护及生物多样性保护方面有重要意义。本文对中国西北干旱区不同气候区常见的柽柳（Tamarix chinensis）、泡泡刺（Nitraria sphaerocarpa）和柠条锦鸡儿（Caragana korshinskii）灌丛沙堆形态和养分积累特征进行了对比研究。结果表明：柽柳灌丛沙堆高度、面积和体积显著高于泡泡刺和柠条锦鸡儿灌丛沙堆，泡泡刺灌丛沙堆高度、面积和体积最小。3种灌丛的存在都显著增加了沙堆土壤有机质含量，使灌丛沙堆成为“肥岛”，其中柽柳灌丛沙堆“肥岛”效应最明显。柽柳灌丛沙堆土壤有机质、全碳、全氮和凋落物含量显著高于泡泡刺和柠条锦鸡儿灌丛沙堆。主要原因是柽柳枝条茂密，拦截面积大且凋落物量大，因此沙物质拦截和养分积累能力强于其他两种灌丛。另外，不同气候区沙源和气象条件的差异也可能导致灌丛沙堆形态及养分累积特征不同。

Nebkha morphological characteristics and soil nutrition content in three regions with different climates in North China

Nebkhas,or vegetated sand dunes,are a common landscape in the transitional zone of oasis and desert in arid and semi-arid regions. And,nebkhas are critical in preventing desertification and biodiversity protection of oasis. This paper studied the differences of nebkhas morphology characteristics and soil nutrition content among three types of nebkhas(Tamarix chinensis,Nitraria sphaerocarpa and Caragana korshinskii) which from different regions. The results are as follows:The height,area and volume of T. chinensis nebkha were significantly higher than N. sphaerocarpa and C. korshinskii nebkhas. And the height,area and volume of N.sphaerocarpa nebkha were the smallest. The existence of both three types of shrubs were significantly increased soil organic matter,and made nebkhas into"fertile island". Soil organic matter,total carbon,total nitrogen and total phosphorus of T. chinensis nebkha were all significantly higher than N. sphaerocarpa and C. korshinskii nebkhas. The mainly reason was that soil litter content of T. chinensis nebkha was the highest,and the growth habit of T. chinensis are vertical,dense,and multi-branching. Thus,the interception and accumulation capability of T.chinensis nebkha is stronger than N. sphaerocarpa and C. korshinskii. In addition,the differences of sand source and meteorological condition among different regions may also lead to the differences of morphological characteristics and soil nutrition content of nebkhas.