There is 70% of organic substance in tannery sludge, which is a high-quality fertilizer. But too much chrome becomes the major obstacle for tannery sludge agricultural application. The experiment study shows that after entering into soil, 96%-98% of Cr 3+ was fixed by chemical adsorption. Its thermoisopleth conforms to Freundlish adsorption isothermal pattern. The empirical equation of adsorption thermoisopleth is as the following:light loam:S=0.912C 0.795 ,middle loam:S=0.946C 0.824 ,heavy loam...