Main Herbaceous Plants Adapted To Arid Environment With Seed Treatment And Soil Improvement In Mu Us Desert

The growth, soil nutrients, enzyme activities and bacterial community diversity on the pot experiment for Astragalus adsurgens P. and Medicago sativa L. were studied, which would provide a theoretical basis for Astragalus adsurgens P. and Medicago sativa L. to adapt arid sand area. The main conclusions are as follows:1) Using the different contents of water retaining agent on Astragalus adsurgens P. seeds, through experimental analysis on germination and seedling growth and drought resistance drew the following conclusions. The suitable content of water retaining agent are from7%to9%when pelletizing.2) In order to evaluate the microbial ecology in rhizosphere of Medicago sativa L. after rhizobium and arbuscular mycorrhizae fungi(AMF) inoculation, soil nutrients, enzyme activities, and bacterial functional diversity were measured of three treatments:(1) rhizobium inoculation;(2) AMF inoculation:(3) rhizobium and AMF combination. There were significant effects on Medicago sativa L. seedling biomass, rhizosphere ammonium nitrogen, nitrate nitrogen, and quick-release phosphorus,after all three treatments; there were no significant changes in quick-release potassium, phosphatase, urease, and proteinase in rhizosphere; the combined inoculation of rhizobium and AMF showed more significant effects than individual inoculation of rhizobium and AMF respectively. The combined inoculation increased the nitrogen source utilization rate than rhizobium and AMF individual inoculation and there was no significant difference between rhizobium and AMF. All treatments had influence on rhizosphere microbial nitrogen utilization in different levels and the treatments also changed the nitrogen utilization preference. The correlation analysis showed that the soil microbial functional diversity was highly correlated with soil nutrients at the level of0.05(p=0.05); and the root was evaluated by AMF successfully.3) Medicago sativa L.-Microcolus vaginatus-azotobacter was constructed artificially by inoculated with AMF, rhizobium and Microcolus vaginatus. Seedling biomass, soil nutrients, enzyme activities were analyzed and came following conclusions. In the Medicago sativa L.-Microcolus vaginatus-azotobacter system, seedling biomass improved28.33%; rhizosphere ammonium nitrogen, nitrate nitrogen, and quick-release phosphorus was affected significantly, inoculating with Microcolus vaginatus affected surface soil organic matter content significantly, but no significantly effects on root inter-soil organic matter content; Sucrase, proteinase, alkalinep hosphata activities in rhizosphere of Medicago sativa L. were improved significantly in Medicago sativa L.-Microcolus vaginatus azotobacter system.