希拉穆仁天然草地不同群落土壤分形特征及其影响因素

(1.内蒙古农业大学 沙漠治理学院, 呼和浩特 010018;2.内蒙古杭锦荒漠生态系统国家定位观测研究站, 内蒙古 鄂尔多斯 017400)

分形维数; 土壤粒径; 荒漠草原; 群落类型

Characteristics of Soil Fractals and the Influencing Factors of Different Plant Communities in the XiLamuren Grassland
WANG Ruidong1, GAO Yong1, DANG Xiaohong1,2, MENG Zhongju1

(1.College of Desert Control Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; 2 Inner Mongolia Hangjin Desert Ecological Position Research Station, Ordos, Inner Mongolia 017400, China)

fractal dimension; soil particle-size; desert steppe; vegetation types

备注

研究希拉穆仁天然草地围封区内不同群落类型土壤颗粒分形特征及其影响因素,以期为荒漠草原土壤风蚀的减少和草地退化防治提供依据。利用土壤粒径质量分布原理与分形学理论,以围封16年荒漠草原的蒙古韭(Allium mongolicum)、银灰旋花(Convoloulus ammannii)、克氏针茅(Stipa krylovii)、羊草(Leymus chinensis)、洽草(Koeleria asiatica)、短花针茅(Stipa brevi flora)6种群落为研究对象,测定和计算土壤颗粒分形维数、粒径组成和水文物理参数,探讨了近自然恢复状态下0—30 cm土层不同群落类型的土壤颗粒分形特征及影响因素。结果 表明:(1)决定该地区土壤颗粒分形维数大小的主要是粉砂和极细砂的百分含量,其次为细砂的百分含量,其余粒级土壤颗粒的影响程度较小; 土壤颗粒分形维数与土壤总孔隙度、毛管孔隙度、饱和蓄水量和吸持蓄水量呈显著正相关,与土壤容重、非毛管孔隙度、滞留蓄水量的相关性不大。(2)6种不同群落土壤颗粒分形维数最大为2.840,最小值为2.490。0—30 cm土层土壤颗粒平均分形维数介于2.575~2.750,从大到小依次为克氏针茅>短花针茅>洽草>银灰旋花>蒙古韭>羊草。6种不同群落类型样地上土壤分形维数随土壤采样深度的变化发生不同的波动规律,整体上均呈线性下降趋势。(3)分形维数可以作为一个衡量土壤结构及草地退化恢复程度的综合性指标。从土壤分形维数及其蓄水性能来看,希拉穆仁天然草地围封区的6种群落改良土壤特性及蓄水功能表现为克氏针茅、短花针茅和洽草群落优于其他3种群落。

The fractal characteristics of soil particles and their influencing factors in different community types in the surrounding area of the Xilamuren grassland were studied in order to provide a basis for the reduction of soil wind erosion and grassland degradation in desert steppe. Using the principle of soil particle size mass distribution and fractal theory to of desert steppe, the fractal dimension, particle size composition and hydrophysical parameters of soil particles of six 16-year enclosed communities of Allium mongolicum, Convoloulus ammannii, Stipa krylovii, Leymus chimensis, Koeleria glauca, Stipa brevii were determined to investigate the fractal characteristics and influencing factors of soil particles in different conmunity types und the near-natural recovery. The results showed that:(1)the fractal dimension of soil particles in this area mainly depended on the percentages of silt and very fine sand, followed by the percentage of fine sand, and the influence of other grain-level soil particles was little; fractal dimension of soil particles was significantly positively correlated with soil total porosity, capillary porosity, saturated water storage capacity and water storage capacity, and had little correlation with soil bulk density, non-capillary porosity, and retained water storage;(2)the maximum fractal dimension of soil particles in 6 different communities was 2.840, and the minimum value was 2.490, the average fractal dimensions of soil particles in 0—30 cm soil laver varied between 2.575 and 2.750, the average fractal dimensions of soil particles decreased in the order: Stipa krylovii>Stipa brevii>Koeleria glauca>Convoloulus ammannii>Allium mongolicum>Leymus chimensis; the fractal dimensions of soil fractals of six different community types varied with the depth of soil sampling, and showed a linear decline trend with increase of soil depth;(3)fractal dimension can be used as a comprehensive index to measure the degree of soil structure and restoration of grassland degradation. According to the fractal dimension of soil particles and its water storage performance, the improved soil characteristics and water storage functions of communities of Stipa krylovii, Stipa brevii and Koeleria glauca are superior to those of the other communities.