关键词: 沙质土壤, 城市污泥, 层次分析法, 重金属

Abstract: To solve the problems of poor sandy soil and nutrients deficiency for vegetation growth in Beijing suburbs, this paper conducted pot experiments to investigate the effects of increasing proportion of municipal sludge on rape growth and physical and chemical properties of sandy soil. The growth of rape, contents of nutritional composition and effective concentrations of heavy metals were all measured. The analytic hierarchy process was used to build selective analytic model for improving sandy soil by sludge, and optimal sludge additive amount was determined. The results showed that moderate amount of sludge could effectively improve the contents of organic matter, total nitrogen and available phosphorus in sandy soil, and was beneficial for the growth, germination rate, plant height and biomass increase rate of rape, which were 10%, 131.55% and 58.84%, respectively. The results of heavy metal risk assessment showed that the soil was at cleaning level, when sludge concentration was below 20%. The evaluation result of analytic model indicated that 3% was the optimal sludge additive amount. These results  provided certain theoretical basis for sludge resource utilization and sandy soil improvement in Beijing suburbs in the future.

Key words: sandy soil, municipal sludge, analytic hierarchy process, heavy metal