Changes of some major and micro nutrients during the decomposition process of oak twigs
几种常微量元素在辽东栎枝条分解过程中的变化特征

With the litterbag method,the decomposition of twigs of oak ( Quercus liaotungensis ),was investigated in five years consecutively.Changes of concentrations and the remaining percentage of five nutrient elements,Ca,Mg,Cu,Zn,Mn,were determined.It was found that changes of concentrations and remaining percentages differed within those five nutrient elements throughout the five year decomposition.Concentrations of all those five nutrients were found increasing at the beginning stage of twig decomposition.However,concentrations of Ca and Zn continually increased in the middle stage of decomposition,while of Mg,Cu,and Mn began to decrease.Based on Olson exponential equation,the constant, k , of Mn is a little bit higher than that of Mg,and two times more than of that Zn.However,the mass loss constants of those elements are much lower than of some major elements,such as N,P,and K.