Leachate Nutrient Analysis and Dynamics of Litter and Topsoil of a Quercus variabilis Forest in the West Mountains near Beijing

Rainfall is a major source of nutrients for forest ecosystems, and the subsequent leaching from forest litter contributes to nutrient cycling. In an effort to examine leachate dynamics from forest litter and topsoil, a field experiment was conducted over 7 months in a Quercus variabilis forest in the West Mountains, near Beijing. The seasonal patterns of concentrations of the nutrients studied differed. Concentrations of NH4-N, TP (Total P), K, Ca, and Mg in litter leachate were higher than those in the topsoil leachate. In both leachates, Ca had the highest overall proportion of the nutrients studied, followed by K, NO3-N, NH4-N, TP, and Mg in the litter leachate, and by NO3-N, K, NH4-N, TP, and Mg in the topsoil leachate. NH4-N, NO3-N, and Ca in both leachates had significant positive relationships. The rain-based fluxes of Ca, inorganic N (NH4-N, NO3-N), and K from the litter leachate were 73, 43, and 23 kg/ha/year, respectively. Consequently, forest litter appears to be a nutrient source in the Quercus variabilis forest, especially for Ca, inorganic N, and K, and nutrients from the forest litter appear to have an important effect on topsoil. This can provide data support for forestry engineering.