Abstract:To reveal the fractal characteristics of soil pores in artificial Salix psammophila forest land with different stubble periods in Mu Us Sandy land and clarify the influence of stumping cycle on soil pore structure characteristics, this paper takes the soil of Salix psammophila forest land , which was regularly bred by the local forestry department according to the flat period of 3a, 5a and 7a, was used as the research object. Based on the low temperature nitrogen adsorption test, the pore structure parameters and isothermal adsorption curves of 0-50 cm soil in Salix psammophila forest land with different cropping periods were measured. The fractal dimension of pore surface was calculated by Frenkel-Halsey-Hill model, and the relationship between pore structure parameters and fractal dimension of pore surface was analyzed.The results showed that: (1) The soil pore size of the forest in the study area was mainly mesopores (2~50nm), with a small number of micropores (≤2nm) and large pores (≥50nm). (2) The fractal characteristics of soil pore structure in Salix psammophila forests with different flat periods are obvious. The fractal dimension ranges from 2.4971 to 2.7797 with an average of 2.6849, which can describe the fractal characteristics of soil pore surface and pore structure even better. (3) The fractal dimension of forest soil under different flat periods is closely related to the pore structure parameters. The larger the fractal dimension, the coarser the pore surface and the higher the irregularity. (4) The flatness of vegetation affects its regeneration and rejuvenation. For Mu Us Sandy land, where Salix psammophila is the main tree species for preventing wind and fixing sand, the flat stubble period is 5a, which is more suitable for forest land soil development and keeping the structure stable. It can be seen that reasonable plain stubble cycle is beneficial to the growth of local Salix psammophila forest and the stability of soil. So the results of this study can provide theoretical guidance for the management and management of Salix psammophila plantation, and promote Salix psammophila plantation to achieve the predetermined production and management objectives.