Abstract:Uranium-contaminated soil in mining area was taken as research object, and ryegrass and pakchoi were selected for intercropping treatment. Through pot experiment, dynamic absorption characteristics of plant intercropping on soil uranium and influence of plant roots in intercropping system on types and contents of organic acids in rhizosphere soil were explored. The results show that sampling at different stages of plant growth, it is found that aboveground biomass of ryegrass and pakchoi in intercropping mode reached the maximum at 7th and 6th week of harvest period, which is 562.577 mg/pot and 344.507 mg/pot, respectively. In middle and late growth stages, aboveground and root uranium accumulations of ryegrass and pakchoi also reach a maximum value of 142.969 g/pot and 65.727 g/pot, respectively. Under intercropping mode, uranium content in rhizosphere soil of ryegrass and pakchoi has significantly differences under different harvest times. During first four weeks of growth period, uranium content in rhizosphere soil drops slowly. From fifth week, uranium content in rhizosphere soil shows a significant decreasing trend, and drops to 124.5 mg/kg and 145.167 mg/kg respectively in near harvest period, which is about 40% lower than in early growth period. Types of organic acid of ryegrass and pakchoi in rhizosphere soil under intercropping mode are bigger than those in other treatment groups. Uranium content in aboveground and rhizosphere of intercropping ryegrass and pakchoi is positively correlated with main indicators in rhizosphere soil microenvironment.