as shown in figure 1, a majority of heavy metals ni and cd accumulated in the experimental soil. accounting for 58%-89% of the experimental soil before experiment. the concentratins of heavy metals ni and cd after planting were in direct proportion to the additive amount of composted sludge. meanwhile, the accumulation coefficients of ni the soils of corn and wheat in same experimental program were in agreement with each other, whereas the accumulation coefficient of cd was obviously various. this indicated that the retention of experimental soil to ni and cd varied, and the retention proportion was cd>ni.