Effects of coal mining subsidence on the rhizosphere environment of Artemisia ordosica in Mu Us sandland,northwest China

Taking the rhizosphere soil of Artemisia ordosica in Mu Us sandland as an example, the effects of soil physi chemical properties, soil microorganism and enzyme activities after 1-3 years subsidence were analyzed. The results showed that soil bulk density and field capacity decreased, and rhizosphere soil available phosphorus, potassium and nitrogen content decreased significantly (P<0.05) after subsidence, but soil pH and conductivity increased significantly compared with the un disturbance area. The quantities of bacteria and actinomycetes decreased in the depth of 0-20 cm, while the quantities of fungi increased. As compared to the un disturbance area, soil microbial quantity increased in the 20-40 cm and 40-60 cm layers. Soil acid phosphatase activity increased significantly after subsidence (P<0.05). Soil invertase activity in the surface increased significantly after 2-3 years subsidence, while there was no significant difference in the deep soil (P> 0.05).There was no significant difference on soil available phosphorus and nitrogen, the quantities of bacteria in surface soil, soil urease and invertase activity between subsidence area and the un disturbance area after 3 years. The rhizosphere environment of plants has a certain self repair capacity, but it will take a long time to reach the level of nature eco environment after mining subsidence.