Effects of litter decomposition on soil nutrients in three broad-leaved forests

Nutrients in soils of Quercus variabilis forest,Juglans mandshurica forest and Q.aliena forest in Baxian Mountain National Nature Reserve in Tianjin were measured as affected by different litter layers:fresh litter,half-decomposed litter and soils.The results showed that in the fresh litter,C content was highest in the Q.aliena forest(486.1 g·kg-1) and lowest in the Q.variabilis forest(447.5 g·kg-1),and N and P contents were highest in the J.mandshurica forest(17.9 and 1.2 g·kg-1) and lowest in the Q.aliena forest(13.2 and 0.8 g·kg-1).In the half-decomposed litter,C and P contents were not significantly different among the three forests;N content was highest in the Q.aliena forest(17.1 g·kg-1) and lowest in the Q.variabilis forest(10.5 g·kg-1).The contents of C,N and P varied in the soils of the different forests:Q.aliena forest J.mandshurica forest Q.variabilis forest.In the fresh litter,C / N and C / P were significantly lower in J.mandshurica forest than in Q.aliena forest and Q.variabilis forest;in the half-decomposed layer,C / N and C / P were not significantly different among the three forests.From the fresh layer to the half-decomposed layer of litter,C / N and C / P were decreased by 17% and 11% in Q.variabilis forest,by 19% and 35% in Quercus aliena forest,but not significantly different in J.mandshurica forest.The mineral element content in the fresh litter tended to decrease from J.mandshurica forest,to Q.variabilis forest,and Q.aliena forest;pH increased with increasing the mineral element content.The order of total content of mineral element in the litter was Q.variabilis forest Q.aliena forest J.mandshurica forest.