Abstract:

Batch experiments  were conducted to investigate the sorption of dissolved organic matter (DOM) derived from straw and sludge treated with freezethaw  on black soil. The results showed  that in  most cases, the DOM that  can  not be adsorbed onto the black soil  facilitated the release of the organic matter from black soil in the range of the equilibrium concentration of DOM. Compared with the DOM from non\|frozen straw and sludge, the DOM from the straw and sludge treated by freeze\|thaw  increased the desorption and release  of the organic matter of black soil obviously, and it was greatly affected by the pH value, ion strength and ion type of the solution system. The desorption of the organic matter of black soil by DOM increased with the increase of pH and the decrease of ion strength. When the ion type was CaCl2 of divalent cation, the desorption of the organic matter of black soil by DOM was greater than
 that when the ion type was  monovalent cation. In the presence of  the different anions, the desorption order  of the organic matter of black soil by DOM was Cl^->SO^2-₄>NO^-_3.

Key words: freezethaw, dissolved organic matter, adsorption, black soil