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

摘要： 针对京郊沙质土壤贫瘠，植被生长缺乏营养物质等问题，采用盆栽实验研究了污泥添加量对油菜长势及沙质土壤理化性质的影响，测定了油菜长势、营养成分的含量以及重金属的有效浓度，并采用层次分析法构建了污泥改良沙质土壤方案选取分析模型，确立了最佳污泥添加量。结果表明，适量的污泥可有效改善沙质土壤中有机质、全氮和有效磷的含量；且有利于油菜的生长，油菜的发芽率、株高和生物量的增加率分别达到10%、131.55%和58.84%。重金属风险评价结果表明，当污泥浓度低于20%时，土壤处于清洁状态。分析模型评价结果表明3%为污泥的最佳添加量，为今后污泥的资源化利用以及京郊沙质土壤的改良提供了一定的理论依据。

关键词: 沙质土壤, 城市污泥, 层次分析法, 重金属