Yan Xin, An Hui
Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan 750021, China.
Ying Yong Sheng Tai Xue Bao. 2017 Oct;28(10):3243-3250. doi: 10.13287/j.1001-9332.201710.024.
The variation of soil properties, the fractal dimension of soil particle size, and the relationships between fractal dimension of soil particle size and soil properties in the process of desertification in desert grassland of Ningxia were discussed. The results showed that the fractal dimension (D) at different desertification stages in desert grassland varied greatly, the value of D was between 1.69 and 2.62. Except for the 10-20 cm soil layer, the value of D gradually declined with increa sing desertification of desert grassland at 0-30 cm soil layer. In the process of desertification in de-sert grassland, the grassland had the highest values of D , the volume percentage of clay and silt, and the lowest values of the volume percentage of very fine sand and fine sand. However, the mobile dunes had the lowest value of D , the volume percentage of clay and silt, and the highest value of the volume percentage of very fine sand and fine sand. There was a significant positive correlation between the soil fractal dimension value and the volume percentage of soil particles <50 μm, and a significant negative correlation between the soil fractal dimension value and the volume percentage of soil particles >50 μm. The grain size of 50 μm was the critical value for deciding the relationship between the soil particle fractal dimension and the volume percentage. Soil organic matter (SOM) and total nitrogen (TN) decreased gradually with increasing desertification of desert grassland, but soil bulk density increased gradually. Qualitative change from fixed dunes to semi fixed dunes with the rapid decrease of the volume percentage of clay and silt, SOM, TN and the rapid increase of volume percentage of very fine sand and fine sand, soil bulk density. Fractal dimension was significantly correlated to SOM, TN and soil bulk density. Fractal dimension 2.58 was a critical value of fixed dunes and semi fixed dunes. So, the fractal dimension of 2.58 could be taken as the desertification indicator of desert grassland.
探讨了宁夏荒漠草原荒漠化过程中土壤性质的变化、土壤粒径分形维数以及土壤粒径分形维数与土壤性质之间的关系。结果表明，荒漠草原不同荒漠化阶段的分形维数（D）变化较大，D值在1.69至2.62之间。除10 - 20 cm土层外，0 - 30 cm土层荒漠草原的D值随荒漠化程度的增加而逐渐下降。在荒漠草原荒漠化过程中，草原的D值、黏土和粉砂体积百分比最高，极细砂和细砂体积百分比最低。然而，流动沙丘的D值、黏土和粉砂体积百分比最低，极细砂和细砂体积百分比最高。土壤分形维数值与<50μm土壤颗粒体积百分比呈显著正相关，与>50μm土壤颗粒体积百分比呈显著负相关。50μm粒径是决定土壤颗粒分形维数与体积百分比关系的临界值。土壤有机质（SOM）和全氮（TN）随荒漠草原荒漠化程度的增加而逐渐降低，但土壤容重逐渐增加。从固定沙丘到半固定沙丘发生质的变化，黏土和粉砂体积百分比、SOM、TN迅速下降，极细砂和细砂体积百分比、土壤容重迅速增加。分形维数与SOM、TN和土壤容重显著相关。分形维数2.58是固定沙丘和半固定沙丘的临界值。因此，分形维数2.58可作为荒漠草原荒漠化指标。
