Nutrition dynamic analysis of litter layer in the plantations of Beijing mountainous area

In order to study the effects of various plantation management models on soil fertility,in 2000,the quantity,nutrition,composition and decomposing rate of litter layer in the plantations of Larix principis-rupprechtii,Pinus tabulaeformis,Fraxinus chinensis and secondary forests mixed by Tilia mandshurica,T.mongolica,Quercus liaotungensis and Populus davidiana were studied in the sample plots of Jiulongshan Mountains in Beijing.The results showed that: 1) litter storage under the plantations and forests followed the order of Pinus tabulaeformisthe mixed forestsLarix principis-rupprechtiFraxinus chinensis;2) there is a positive correlation between nutritional quantity per area and litter storage as well as element content;3) decomposition rates of the litter of Larix principis-rupprechtii and the mixed forests were faster than those of Pinus tabulaeformis and Fraxinus chinensis;4) as to the total quantity of N,P and K returning to soil from the decomposed litter,Larix principis-rupprechtii is the largest,then the mixed forests,Pinus tabulaeformis and Fraxinus chinensis are the smallest.