大兴安岭低质林诱导改造后土壤呼吸影响因子

Influence Factors of Soil Respiration in Low Quality Forests After Induced Transformation in Great Xing'an Mountains

对大兴安岭地区阔叶低质林进行6、10、14、18 m带宽皆伐后,并种植西伯利亚红松(Pinus koraiensis)进行诱导改造,利用LI-8150多通道土壤碳通量自动测量仪测定土壤表面CO2通量,分析不同带宽诱导改造土壤呼吸速率的影响因子。结果表明:不同带宽土壤呼吸速率均高于对照样地,表现为18 m带宽6.51μmol.m-2.s-1>10 m带宽5.33μmol.m-2.s-1>14 m带宽5.26μmol.m-2.s-1>6 m带宽3.53μmol.m-2.s-1>对照样地3.12μmol.m-2.s-1。在Spearman相关性检验中,不同带宽诱导改造后土壤密度与土壤呼吸速率呈现显著负相关性,土壤有机质、半分解层枯落物质量与土壤呼吸速率表现出显著正相关性(p<0.05)。6 m带宽、10 m带宽、14 m带宽、18 m带宽和对照样地的土壤呼吸敏感指数(Q10)值分别为3.72、1.09、2.77、4.31和2.58。随着土壤含水量的升高土壤呼吸速率逐渐升高,但达到一定临界值后土壤呼吸速率呈现出下降的趋势,而不同诱导改造林这一临界值不同。

Clear cutting was made in low quality mixed forests in Great Xing＇an Mountains according to different bandwidth of 6,10,14 and 18 m,and induced transformation was performed by planting Pinus sibirica.Then LI-8150 multi-channel soil carbon flux automatic measuring instrument was used to measure soil surface CO2 flux,and the influences of induced transformation with different bandwidth on soil respiration rate were analyzed.Results indicated that soil respiration rates in the low quality forests with different bandwidth were higher than that of the check plot.The soil respiration rate for 18m bandwidth（6.51 μmol^-2·s^-1was highest,followed by 10 m bandwidth（5.33）,14 m bandwidth（5.26）,6 m bandwidth（3.53）,and the check plot（3.12）.Spearman correlation analysis showed that there was significant negative correlation between soil bulk density and soil respiration rate after different bandwidth of induced transformation,while significant positive correlations were observed between soil organic matter content,litter mass in the semi-decomposed layer and soil respiration rate.Sensitivity indices of soil respiration for 6,10,14,18 m bandwidth and the check plot were 3.72,1.09,2.77,4.31 and 2.58,respectively.Soil respiration rate increased gradually with increasing soil water content,but it showed a downward trend when soil water content reached a certain critical value.The critical values of soil water content were various for the forests after different induced transformation.