采伐剩余物管理措施对杉木人工林土壤呼吸的影响

摘要

We measured monthly soil respiration (Rs) in a 15 year-old replanted Chinese fir plantation which was located in subtropical China and subjected to five harvest residue management treatments.The treatments included:whole tree harvest plus forest floor removal,whole tree harvest,stem only harvest,double the residue,and burning the residue.Repeated measures ANOVA showed that harvest residue management had little effects on Rs rate,soil temperature and soil moisture in the whole year or four different seasons.Soil respiration displayed obvious seasonal dynamics,with the maximum happening in June 2012 (3.09 μmol C02·m-2s-1,averaged from five treatments) and the minimum happing in February 2012 (0.69 μmol CO2· m-2s-1).Soil temperature was found to be the most important factor controlling the temporal pattern of soil respiration,accounting for 55.8％-72.6％ of variations in Rs rate.There were no significant differences in temperature sensitivity of Rs (Q10) and annual soil CO2 emission among treatments,and the mean values of five treatments were 2.14 and 701.17 gC·m-2,for Q10 and annual soil CO2 emission.Harvest residue treatment had no significant effects on dissolved organic carbon (DOC) concentrations (0-10 cm depth) extracted by water,hot water or 2 mol· L-1 KC1.DOC concentrations extracted by water and 2 mol· L-1 KC1 were correlated positively with annual Rs rate and the Rs rate in the given month when soil samples were collected,restpectivelv.%对中国亚热带地区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、采伐剩余物加倍以及炼山)下杉木人工林的土壤呼吸进行定位研究.结果表明:处理15年后5种采伐剩余物管理措施对杉木林全年和不同季节的土壤呼吸速率、土壤温度以及土壤湿度均没有显著影响；土壤呼吸速率呈明显的季节动态,最高值出现在2012年6月(3.09 μmolCO2·m-2 s-1,5种处理平均值),最低值则出现在2012年2月(0.69 μmolCO2·m-2s-1)；土壤呼吸速率主要受土壤温度的驱动,土壤温度能解释土壤呼吸速率变化的55.8％ ～72.6％；5种处理样地之间土壤呼吸Q10值和年通量差异均不显著,处理样地的平均值分别为2.14和701.17gC·m-2；采伐剩余物管理措施对0 ～ 10 cm土层冷水、热水和2 mol·L-1KC1溶液浸提的土壤可溶性有机碳含量没有显著影响；冷水和2 mol· L-1 KC1溶液浸提的土壤可溶性有机碳含量分别与取样月份和年均土壤呼吸速率显著正相关(P＜0.05).