Effect Of Different Ages Artemisia Sphaerocephala On Soil Nutrients Of Alxa Desert

Land desertification is a serious problem that needs human to face, currently, plant sand-fixation is one of the most effective ways to prevent and control sandy desertification. In this study,5,10,15, and20-year-old Artemisia sphaerocephala were selected to study the effect of different ages Artemisia sphaerocephala on soil nutrients of Alxa Desert. pH values, nutrients content, organic carbon content, and their relationship were analysized in rhizosphere, non-rhizosphere soils, as well as in different soil layers. The research provided a theoretical basis for controlling shifting sand and protecting ecological environment.The results revealled as follows:An obvious rhizosphere effect appeared in rhizosphere soil of Artemisia sphaerocephala: distinct acidification was found at the rhizosphere of15and20year-old Artemisia sphaerocephala, however, no obvious change appeared in the remaining two planting years. Organic carbon content in rhizosphere soil was higher than that in bulk soil, the highest enrichment rate among them appeared in10-year-old Artemisia sphaerocephala growing soil, which was87.5%. With the increasing of growing years, total and available N and P in rhizosphere soil increased, the available content showed enrichment capacity further, such as the highest enrichment rate of ammonium, nitrate and available P were91.15%,115%and127.30%, respectively. Moreover, the content of total Fe, Mn, and Zn in rhizosphere was less than that in non-rhizosphere soils, in contrast, the available content of the three micronutrients was higher in rhizosphere than that in bulk soils, for example, Mn was accumulated significantly in rhizosphere with the increment of planting years, highest enrichment rate was85.24%which appeared in twenty-year-old Artemisia sphaerocephala growing soil. In addition, total Cu content was consistent with available Cu, both of them showed negative enrichments, however, their content in rhizosphere decreased with increasing ages. Overall, There is a complicated correlation between soil nutrients in rhizosphere and bulk soil, all kinds of nutrient elements have interactions and synergistic effects. Correlation in the rhizosphere soil is significantly stronger than that in the bulk soil.Artemisia sphaerocephala had an impact on nutrient distribution in vertical direction of different soil layers. pH increased with the increment of soil depth, with the minimum on surface soil (0-10cm), pH also decreased with the increment of planting years at the same soil layer. The content of organic carbon, total nitrogen, ammonium, nitrate, total and available P decreased as the increment of soil depth, but increased in various degrees as the increment of planting years, however, the content of ammonium was minimal and did’t change significantly due to the nitrification. With the soil deepening, the content of total and available trace elements showed a downward trend. As the increment of planting years in the same soil layer, total and available Fe and Mn showed a upward trend, but total and available Cu, Zn were on the contrary. Compared with contrast,15and20-year-old Artemisia sphaerocephala had a significant higher content of nutrient elements in surface soil (0-20cm).