According to Lin Xiangui et al. “Principles and Methods of Soil Microbial Research” combined with the requirements of this project, a unified sampling specification and method were developed for sampling. In the Maowusu sandland, three representative sand-fixing shrublands, Artemisia spp., Salix spp. and Citrus aurantium spp. were selected to be planted in the same year, and three sample plots of 20m×20m were randomly set up in each type of shrubland, with a spacing of 20m between plots, meanwhile, the bare sandland was selected as a control at a distance of less than 20m from the shrubland.

  Soil samples were taken in August, when plant growth was most vigorous and microbial activities were most active. In each sample plot, five shrubs were randomly selected, and a sterilized soil auger with a diameter of 2.5 cm was used to take the soil under the shrubs and between the shrubs in the depth range of 0-10 cm, and the surface plant litter was removed before collecting the samples. The soil samples collected from each sample site were mixed into one mixed sample (about 1000g) according to the soil samples under shrubs and among shrubs, put into sterile plastic bags, kept in a heat preservation box, and quickly transported back to the experiment station, and the mixed soil samples were sieved through a 2mm sieve to remove the root system and litter. After sieving, each soil sample was immediately stored at -20°C for high-throughput sequencing.