| Manure fertilization is very popular in agricultural production, which is very important for improving soil fertility, bettering soil quality, increasing crop yield and quality. As dissloved organic matter is the most active component in manure, it will have great influence on the soil fertility, soil physical and chemical property and validity of microelement especially for some contaminated elements through a series of process including sorption, desorption, transfer, transformation and and chelation related to soil organic and inorganic colloid when dissolved organic matter (DOM) entered soils. It is significant to study the chemical behavior of DOM and its effluence on pollutant elements for evaluating the effects of organic manure ferlization, the relationship between organic manure and soil fertility.DOM used in this paper was obtained from that of chicken dung compost after special chemical treatment, and the selected materials were black soil, brown soil and red soil. The behavior of DOM including sorption, desorption and fixation in soils, particularly, the effects of DOM on copper fractional distribution was studied. The effects of DOM on crop growth in the three kinds of soil contaminated by copper were also explored using potted plant experiment. The main results from this paper can be described as follows:(1)Once DOM entered into soils, most will be absorbed by soil colloid. The sorption and desorption of DOM in soils will reach a balance in a hour with such a rapid process. There is great difference among the absorbing ability of various kinds of soils, and the absorbed amount of DOM is relatively high in Black soil with more organic matter content and red soil with lower pH with more rapid speed. The distribution coefficients of DOM in black soil, red soil and brown soil are 26.57, 22.31 and 16.72 separately.As the adsorption of DOM in soils is a reversible process, the DOM adsorpted by soil can return to soil solution under proper conditions. The soils with stronger adsorption ability of DOM can release more DOM into soils through desorption, while soils with less absorbing ability combined more tightly with DOM. The desorption amound of red soil, black soil, and brown soil are about 90%, 50%～60%, and 40% of the adsorption amound.(2) Once the DOM entered into soils, it can also be fixed except for sorption. The fixation of DOM in soils is closely correlated with its sorption. Generally, soils with stronger absorbing ability can stabilize more DOM and more DOM will be fixed with the temperature increased.(3) DOM from outer source has very important impact on the fractional distribution of heavy metals. The fractional distribution of heavy metals in soils will change immediately once DOM comes into soils, with the increased rate of exchange form firstly which means the heavy metal activatation role of DOM(36.33% higher at most). The exchangeable content of heavy metals will be reduced with the change of chemical behavior of DOM in soils when it was increased to a high level, but the total amount of exchangeable heavy metals remained at a higher level than that in original soils with such a long time(6.74%～26.45% higher after 28 days). Soil temperature can have great impact on heavy metal fractions with the existence of DOM. With the soil temperature increased, DOM has influence on the heavy metal fractions, while less influence from DOM can be observed at lower temperature.(4) The influence of DOM on heavy metal fraction in soils can be regarded a comprehensive process. The validity of heavy metals was reduced with the pH increased in spite of that heavy metals be activated by DOM in soils(the pH increase 0.15-0.21 when the concentration of DOM is 1000 mg C-kg-1). The process was mainly controlled by activation effect when adding low level of DOM, and more amounts of heavy metals was activated with more DOM added. However, when the added DOM reached at a high level, the increasing effect of pH in soils occurred, and less activation effect will be found with DOM content increased. In addition, the activation effects of DOM on heavy metals in soils was correlated with soil properties, and less activation effects was observed with more organic content and higher pH values.(5) The growth of crops was greatly affected by DOM since the heavy metals were activated by DOM in soils contaminated by heavy metals, which resulted in toxic effects of crops; yield reduction, higher concentration of heavy metals in plant tissues and crops quality degradation.According to this research, adding manure using is not an in point way to rehabilitate heavy metal pollute soil in all conditions. When using manure in heavy metal pollute soils, must think over the influence of DOM, and feel one's way.
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