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

根据福建省南平市峡阳国有林场二代杉木(Cunninghamia lanceolata(Lamb.) Hook)人工林5种采伐剩余物管理措施(收获采伐剩余物和地被层、全树收获、仅收获树干和树皮以及加倍采伐剩余物、炼山)下0-40 cm深度土壤全碳、全氮含量15a的监测数据,研究了采伐剩余物管理措施对杉木林土壤碳氮含量的影响.结果显示,加倍采伐剩余物处理样地5次取样年份(造林第3年、第6年、第9年、第12年和第15年)0-10 cm土层土壤全碳、全氮含量均高于其他处理样地,但单因素方差分析显示,采伐剩余物管理措施在5次取样年份对0-10 cm、10-20 cm和20-40 cm土层全碳、全氮含量均没有显著影响(P＞0.05).重复测量方差分析显示,杉木造林15a期间土壤全碳、全氮含量随年份显著变化(P＜0.01),但处理措施以及处理措施与取样年份的交互作用对3个土层土壤全碳、全氮含量影响不显著(P＞0.05).杉木林15年生时,不同处理样地3个土层碳储量差异不显著(P＞0.05),0-40 cm土层平均值为88.71 Mg/hm2.表明采伐剩余物管理措施对亚热带杉木人工林土壤全碳、全氮含量的长期效应并不显著.

Long-term effects of harvest residue management on soil total carbon and nitrogen concentrations of a replanted Chinese fir plantation

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 (P >0.05). Analysis of repeated-measures ANOVA showed that C and N concentrations for the three depth layers varied between years (P<0.01). 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 (P >0.05). 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 (P >0.05). 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.