干旱区研究 ›› 2018, Vol. 35 ›› Issue (3): 713-721.doi: 10.13866/j.azr.2018.03.26

• 其他 • 上一篇    下一篇

高寒沙地植物的沙堆形态特征及其成因分析

吴汪洋1,张登山1,2,田丽慧3,张明远1,周鑫2   

  1. (1. 环境演变与自然灾害教育部重点实验室,北京师范大学地理科学学部,北京 100875;2. 青海大学农林科学院, 青海 西宁 810016;3. 青海大学省部共建三江源生态和高原农牧业国家重点实验室,青海 西宁 810016)
  • 收稿日期:2017-09-03 修回日期:2017-10-31 出版日期:2018-05-15 发布日期:2018-06-01
  • 通讯作者: 张登山.E-mail: dshzhang2008@sina.com
  • 作者简介:吴汪洋(1988-),博士研究生,研究方向为荒漠化防治. E-mail:bnuwwy@163.com
  • 基金资助:
    国家自然基金项目(41661001,41461002);青海省高端千人计划项目资助

Morphologic Features and Forming Causes of Plant Sandpiles in Alpine Sand Land

ZHANG Deng-shan1,2 , TIAN Li-hui3, ZHANG Ming-yuan1, ZHOU Xin2   

  1. (1. Key Laboratory of Environmental Changes and Natural Disaster, Ministry of Education, School of Geography, Beijing 100875, China; 2. Qinghai Academy of Agricultural Forestry Sciences, Xining 810016, China; 3. State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China)
  • Received:2017-09-03 Revised:2017-10-31 Online:2018-05-15 Published:2018-06-01

摘要: 固沙植物沙堆的形态特征是高寒植物生态适应性与防治效益的重要体现,对高寒沙地幼龄人工植物沙堆的形态研究有益于探索植被与风沙的相互关系,以指导生物治沙工作。通过对青海湖东岸主要固沙植物沙堆的形态拟合与蚀积监测发现: ① 强堆积型的沙棘与沙蒿沙堆在堆积高度、面积与体积上均大于弱堆积型或弱侵蚀型的樟子松与小叶杨沙堆,这主要受株高、冠幅等植物生长因子及其交互作用的影响;② 根据8方位蚀积断面观测,各沙堆堆积部位主要在NE-E-SE方位带,沙蒿、乌柳沙堆的蚀积强度具有显著的方位差异,这与同方位输沙强度呈现显著的负相关性。在W、NW、SE等方位,沙堆间的物种差异显著;③ 根据各植物沙堆的固沙强度和林下地表输沙强度分析,沙棘、乌柳、樟子松、小叶杨与沙蒿年均固沙效益分别为40.45%、15.53%、4.69%、4.20%与62.72%,沙棘、乌柳与沙蒿均为优良的固沙树种。

关键词: 高寒沙地, 沙堆形态, 堆积强度, 沙堆断面, 方位差异, 固沙效益

Abstract:

Morphology of plant sandpiles is an important reflection of ecological suitability and sand-fixing benefits of different artificial plants. Based on the explorations of the features and formation causes of sandpiles, the erosion and deposition of plant sandpiles can be instinctively compared to provide some basic reasons for selecting the sand-fixing plant species. It is also vital to reveal the relationship between alpine vegetation growth and wind-blown sand activities. The main sandpiles where five typical sand-fixing plant species were afforested in the Ketu sand land on the eastern shore of Qinghai Lake were focused on. Based on the methods of morphological fitting and sand-deposition monitoring, three-dimensional morphology of vegetation sandpiles was simulated and analyzed with the vegetation investigations and wind-blown sand observations during the period of 2015-2016. Based on the statistic results of the total and sectional deposition depths, intensity and affecting factors of wind-blown sand, we found that: ① The sandpiles with conical, hemispherical or linear shapes could form if Hippophae rhamnoides, Salix cheilophila, Pinus sylvestris, Simon poplar and Artemisia desertorum were afforested. Deep and strong sand deposition could occur on the H. rhamnoides and A. desertorum sandpiles, and the projected area and three-dimensional volume of these sandpiles were larger than those of other three light-erosive or light-depositional plant sandpiles; ② Among the eight directional sections of the sandpiles, sand deposition occurred mainly along the northeast-east-southeast directions. In consequence of significant negative correlations between depositional intensity and sediment transport rate along the same directions, the depositional intensity and direction over all the vegetation sandpiles were quite different, especially over the S. cheilophila, S. poplar and A. desertorum sandpiles. In addition, the deposition depth and intensity changed significantly along the directions of northwest, east and southeast; ③ The morphologic differences of plant sandpiles were mainly affected by vegetation growth, the sand depositional depth of H. rhamnoides and S. poplar sandpiles increased with the increase of plant height and canopy and soil crust, especially with their coupling effects. P. sylvestris and S. poplar sandpiles were strongly affected by the basal diameter and clear bole length. Furthermore, the strong west-northwest-north winter wind affected the sandpile erosion, it was also verified by the significantly negative correlations between the directional sand accumulated depth and sand transport intensity, especially for the S. cheilophila and A. desertorum. Calculated by the sand-fixing intensity and surface sediment transport intensity, we could predict the sand accumulation modulus of the five forest dunes, the H. rhamnoides and S. cheilophila forests prevented the sand most with the amount of 400-1 100 t·hm2. because of their high afforesting density and surviving rates. In general, H. rhamnoides, S. cheilophila and A. desertorum could be chosen as the adaptive and efficient sand-fixing vegetation species with sand-fixing benefits of 40.45%, 15.53 % and 62.72% respectively, while the other artificial plant species demand afforesting conservation and structure optimization for their low sand-prevention effects lower than 5%.

Key words: alpine sand land, morphologic feature, depositional intensity, sandpile section, direction difference