Chemical element dynamics in decomposing leaf litter

Abstract

Chemical element change in decomposing aspen and balsam poplar leaves was followed for 60 months in an aspen woodland site in southwestern Alberta, Canada. The changes in concentration and weights of the various elements and in several C:element and element:element ratios are discussed and compared with literature findings and with the concentrations, weights, and ratios encountered in the soil layers.The initial concentrations of all elements, except K and Na, were similar in both aspen and balsam leaf litter; K was higher initially in balsam leaf litter and Na was higher initially in aspen leaf litter. In the decomposing leaf litter, the concentrations of N, Ca, Zn, Mg, Fe, Mn, Cu, and Na generally increased with time while the concentrations of P and K decreased. A decrease in weight was noted for N, P, K, Ca, Mg, and Zn during decomposition while an increase was found for Fe, Mn, Cu, and Na. The order of mobility of elements after 60 months in decomposing aspen and balsam leaf litter was K > Na > P > Zn > Mg > Ca > N > Mn > Cu > Fe. The effects of site aspect on elemental loss, the elemental change in aerial litter bags, the components of elemental change, and models of elemental loss are discussed.