植物生态学报 ›› 2016, Vol. 40 ›› Issue (10): 1003-1014.doi: 10.17521/cjpe.2016.0045

• 研究论文 • 上一篇    下一篇

内蒙古荒漠草原放牧强度对风沙通量和沉积物粒径的影响

李永强1,2,,A;*, 李治国1,,A;*, 董智3, 王忠武1, 屈志强1, 韩国栋1,,A;,A;*   

  1. 1内蒙古农业大学生态环境学院, 呼和浩特 010018
    2土肥资源高效利用国家工程实验室/山东农业大学资源与环境学院, 山东泰安 271018
    3山东农业大学林学院/泰山森林生态站, 山东泰安 271018
  • 出版日期:2016-10-10 发布日期:2016-11-02
  • 通讯作者: 李永强,李治国,韩国栋
  • 基金资助:
    国家自然科学基金(31260123)、国家公益行业专项计划项目(201003019和200903060)和教育部草地资源重点实验室和创新团队支持项目。

Effects of grazing intensity on windblown sediment mass flux and particle size distribution in the desert steppe of Nei Mongol, China

Yong-Qiang LI1,2,*, Zhi-Guo LI1,*, Zhi DONG3, Zhong-Wu WANG1, Zhi-Qiang QU1, Guo-Dong HAN1,**   

  1. 1College of Ecological and Environmental Sciences, Inner Mongolia Agricultural University, Hohhot 010018, China

    2National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources
    College of Resources and Environment, Shandong Agricultural University, Taian, Shandong 271018, China
    and
    3Forestry College of Shandong Agriculture University, Taishan Forestry Ecological Station, Taian, Shandong 271018, China
  • Online:2016-10-10 Published:2016-11-02
  • Contact: Yong-Qiang LI,Zhi-Guo LI,Guo-Dong HAN

摘要:

以内蒙古短花针茅(Stipa breviflora)草原为研究对象, 在放牧11年的样地布设BSNE集沙仪, 通过2013年4月到2015年4月4个采样期对短花针茅草原放牧强度与风沙通量的定量关系及风蚀物粒度特征进行了研究。结果表明: (1)放牧强度对风沙通量有显著影响(p < 0.05)。随着放牧强度增强, 风沙通量逐渐增加; 风沙通量对放牧强度的响应存在季节差异, 生长季的日平均风沙通量小于非生长季, 且生长季不同放牧强度间风沙通量差异较大, 其中重度放牧区风沙通量是对照区的5倍, 而非生长季不同放牧强度间风沙通量差异较小, 重度放牧区是对照区的1.7倍; (2)生长季不同高度风沙通量的自然对数和垂直高度之间存在较好的二项式拟合结果, 而非生长季风沙通量的垂直分布没有明显规律; 放牧强度间通量的垂直分布差异主要表现在0-50 cm高度; 在同样高度, 放牧强度大, 垂直通量也大; (3)风蚀沉积物中粒径≤250 μm颗粒富集度随垂直高度变化而变化; 风沙沉积物中, ≤250 μm的颗粒占沉积物总量的85%以上, 沉积物中粒径≤50 μm的颗粒有明显的富集作用, 且随垂直高度增加富集比逐渐增加; 粒径为125-250 μm和50-125 μm的颗粒表现为随垂直高度增加富集比降低的趋势, 且125-250 μm粒径的富集比显著小于50-125 μm颗粒的富集比; 荒漠草原放牧强度对风沙通量有不同程度的影响, 放牧强度越大, 风蚀越重, 风蚀作用强化了重度放牧对草地退化的影响作用。

关键词: 放牧强度, 风蚀, 风沙沉积物, 风沙通量, 荒漠草原

Abstract:
Aims Grazing activities degrade soil aggregates, reduce vegetation coverage and affect the amount of deposited material, and make the land more vulnerable to wind erosion. Although livestock increase was considered as the main issue leading to the degradation, only very few studies have quantitatively investigated the relationship between grazing and soil erosion. The relationship between different stocking rates and sediment flux, and sediment soil particle was studied to reveal the mechanism of different grazing intensities on soil erosion process, to provide basic parameters for grazing optimization in the Stipa breviflora desert steppe. Methods In the Stipa breviflora desert steppe research area, BSNE collecting sand boxes were set in the randomly distributed paddock experiment sites for 11 year with different grazing intensities (0.15、0.30、0.45、0 sheep·hm-2·month-1, corresponding to light grazing LG, moderate grazing MG, heavy grazing HG and control CK, respectively). The quantitative relationship between grazing intensity and sediment flux, and the characteristics of sediment soil particle were conducted in four sampling periods through 2 years (April 2013 to April 2015).Important findings (1) Grazing intensity had a significant effect on the sediment flux (p< 0.05), and the sediment flux increased with the increase of grazing intensity. The response of sediment flux to grazing intensity was variable with season. The daily average sediment flux (13.12 g·m-1·d-1) during the period of April to October was smaller than that from October to April (18.74 g·m-1·d-1). The sediment flux difference of different grazing intensities was greater from April to October, with the 5 times daily average sand flux in the heavy grazing paddock that in the control. The average sediment flux difference of different grazing intensities was small from October to April. (2) The relationship between the natural logarithm of sediment flux at different height and the vertical height had a better binomial fitting from April to October, and there was no obvious regular pattern about flux vertical distribution from October to April, and the vertical flux difference of grazing intensities was mainly expressed in 0-50 cm layer. (3) Sand sediment particle ≤250 μm accounted for more than 85% of the total sediment, the sand sediment particle of ≤50 μm) size was significantly enriched, and the enrichment ratio increased with the increase of vertical height. The enrichment ratio of 125-250 μm particle and 50-125 μm particle decreased with the increase of vertical height, and the enrichment ratio of 125-250 μm particle was smaller than that of 50-125 μm particle (p< 0.05). Therefore grazing intensity had different influence on the sand flux in Stipa breviflora desert steppe, the greater the grazing intensity, the heavier the wind erosion was, and the effect of grazing intensity on grassland was enhanced by wind erosion.

Key words: grazing intensity, wind erosion, windblown sediments, sediment flux, desert steppe