宁夏荒漠草原沙漠化过程中土壤粒径分形特征

发布时间：2018-09-19 12:16

【摘要】：研究宁夏荒漠草原沙漠化过程中土壤性状、土壤粒径分形维数的变化特征,以及分形维数与土壤性状的关系.结果表明:草地沙漠化对土壤分形维数(D)影响显著,D值为1.69~2.62.除在10~20 cm土层出现较小波动外,随着沙漠化程度加剧,0~30 cm土层D值整体呈减小趋势.在荒漠草原沙漠化过程中,荒漠草地D值最大,黏粒和粉粒体积百分含量最高,极细砂粒和细砂粒体积百分含量最低;流动沙地D值最小,黏粒和粉粒体积百分含量最小,极细砂粒和细砂粒体积百分含量最高.D与50μm和50μm粒径的土壤颗粒存在显著正相关和负相关,表明50μm粒径是决定草地沙漠化过程中土壤分形维数与土壤粒径关系的临界粒径.随着荒漠草原沙漠化加剧,土壤有机质和全氮含量逐渐降低,土壤容重逐渐升高,固定沙地至半固定沙地是荒漠草原沙漠化的质变过程,其中土壤粘粒体积百分含量、粉粒体积百分含量、土壤有机质含量、土壤全氮含量骤减,极细砂粒体积百分含量、细砂粒体积百分含量和土壤容重骤增.分形维数与土壤有机质、土壤全氮和土壤容重显著相关,固定沙地与半固定沙地分形维数的临界值为2.58,因此分形维数2.58可作为荒漠草原沙漠化的退化指标.
[Abstract]:The change characteristics of soil characters, the fractal dimension of soil particle size and the relationship between fractal dimension and soil character in desert steppe of Ningxia were studied. The results showed that the significant effect of desertification on soil fractal dimension (D) was 1.69 ~ 2.62. Except for the small fluctuation in 10 ~ 20 cm soil layer, the D value of 0 ~ 30 cm soil layer decreased with the increase of desertification degree. In the process of desert grassland desertification, the D value of desert grassland is the largest, the volume percent content of clay and silt is the highest, the volume percent content of extremely fine sand and fine sand is the lowest, the D value of flowing sandy land is the least, and the content of clay and silt is the smallest. There was significant positive correlation and negative correlation between the soil particle size of 50 渭 m and 50 渭 m, indicating that the particle size of 50 渭 m was the critical particle size in determining the relationship between soil fractal dimension and soil particle size in the process of grassland desertification. With the increasing desertification of desert steppe, the content of soil organic matter and total nitrogen decreased gradually, and the bulk density of soil gradually increased. It is the qualitative change process of desert steppe desertification from fixed sandy land to semi-fixed sandy land, among which the content of soil clay is percent. The content of silt volume, soil organic matter, soil total nitrogen content, very fine sand volume percent content, fine sand volume percentage content and soil bulk density increased sharply. The fractal dimension was significantly correlated with soil organic matter, soil total nitrogen and soil bulk density. The critical value of fractal dimension between fixed and semi-fixed sandy land was 2.58. Therefore, fractal dimension 2.58 could be used as an index of desertification degradation in desert steppe.
【作者单位】：宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地/西北退化生态系统恢复与重建教育部重点实验室;
【基金】：宁夏高等学校科学研究项目(NGY2017006)资助~~
【分类号】：S812.2

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