采伐剩余物管理措施对二代杉木人工林土壤全碳、全氮含量的长期效应

Abstract

The long-term effects of harvest residue management on total soil carbon(C) and nitrogen(N) concentrations in the mineral soil(to a depth of 40 cm) in a replanted Chinese fir(Cunninghamia lanceolata(Lamb.)Hook) plantation were studied.The plantation was subjected to five harvest residue management treatments including:(1) whole tree harvest plus forest floor removal,(2) whole tree harvest,(3) stem only harvest,(4) double residue,and(5) burning residue.Soil samples were collected in 3,6,9,12 and 15 years after tree replanting.The results showed that there was a trend for C and N concentrations to be higher in double residue treatment than other treatments in 0—10 cm layer during the first 15 years.However,one-way ANOVA showed that harvest residue management had no significant effects on C and N concentrations in 0—10 cm,10—20 cm or 20—40 cm layers at any sampling year(P0.05).Analysis of repeated-measures ANOVA showed that C and N concentrations for the three depth layers varied between years(P0.01).Neither harvest residue management nor the interaction of sampling year and harvest residue management had any significant effects on C and N concentrations in any depth of soil layers(P0.05).Soil C stock at the 0—40 cm depth was 88.71 Mg/hm2 at age 15 years on average.Again,one-way ANOVA showed harvest residue management had no significant effect on the soil C stocks at any soil depths(P0.05).These observations suggested that the long-term effects of harvest residue management on C and N concentrations in Chinese fir plantation were not significant in subtropical China.