【作者】 孟春；

【导师】 王立海；

【作者基本信息】 东北林业大学 ， 森林工程， 2009， 博士

【摘要】 土壤呼吸是指土壤释放CO₂的过程,由3个生物学过程（土壤微生物呼吸、根呼吸、土壤动物呼吸）和1个非生物学过程（含碳矿物质的化学氧化作用）组成,是大气CO₂的重要来源。森林土壤呼吸是陆地生态系统土壤呼吸的重要组成部分,其动态变化将对全球C平衡产生深远的影响。森林作业使森林生态系统结构发生变化,或者使土地利用发生变化,从而导致CO₂释放量的变化,因此,研究森林采伐作业对土壤呼吸的影响有重要的意义。本文利用LI8100土壤二氧化碳排放通量全自动测量系统,采用统计分析的方法,研究了人工林土壤呼吸速率对土壤温度昼夜变化的响应、择伐后土壤呼吸速率对土壤温度和湿度的相应特点、伐根对林隙土壤呼吸的影响、择伐后林地土壤呼吸速率季节变化和年际变化。以上研究均属首次研究。主要研究结果归纳如下:（1）对白桦、胡桃楸、水曲柳、樟子松和落叶松五种人工林林地土壤呼吸速率昼夜变化研究结果表明,林地土壤呼吸速率存在显著的时间异质性。在观测期内,五种人工林土壤呼吸速率昼夜变化呈现出昼高夜低的现象,且昼间峰值只出现一次,具有单峰特点。五种人工林分土壤呼吸速率变化对地表温度和地表下10cm处温度变化呈现非同一路径现象,土壤呼吸速率变化相对于地表温度变化表现出滞后性,土壤呼吸速率变化相对于地表下10cm处温度的变化表现出超前性。地表下10cm处温度是影响土壤呼吸速率变化的主要影响因素。在观测季节内,昼夜内5中人工林出现土壤呼吸速率均值有2个时间区域。（2）对小兴安岭地区典型针阔混交林择伐后林地土壤呼吸速率对土壤温湿度变化的研究表明,择伐未造成土壤温度的显著差异,但择伐使土壤呼吸速率对土壤温度的敏感性发生变化。择伐后林地Q₁₀值高于未采伐林地,土壤呼吸速率对土壤温度的响应略高于未采伐林地,这一现象是3个土壤分室呼吸对土壤温度响应的综合作用的结果。枯枝落叶层呼吸速率对土壤温度的敏感性较差,根呼吸速率和矿质土壤层呼吸速率对土壤温度的敏感性较高。较高强度（60%、71%）的择伐使土壤呼吸速率对土壤温度具有高的敏感性。择伐并未造成土壤湿度的显著差异,土壤呼吸对土壤湿度的响应较弱,土壤湿度不是影响择伐后土壤呼吸速率变化的决定因子。（3）对白桦人工林内林隙内伐根对林隙内土壤呼吸影响的研究表明,伐根对林隙内林地呼吸作用的影响在一个较长的时期内存在,它影响了林隙内土壤呼吸速率的大小和水平空间分布。有伐根林隙土壤呼吸速率高于无伐根林隙土壤呼吸速率,伐根表面的腐朽程度是影响有伐根林隙土壤呼吸速率的主要因素。有伐根林隙土壤呼吸速率相对于无伐根林隙土壤呼吸速率呈现出以伐根为中心向四周辐射,土壤呼吸速率由高变低、再变高的变化规律。有伐根林隙随伐根腐朽程度的增加,土壤呼吸速率水平空间异质性变化梯度最大值降低。（4）对小兴安岭地区典型针阔混交林择伐后土壤呼吸速率季节变化研究结果表明,择伐作业后,土壤呼吸速率呈现规律性的季节变化,林地表面土壤呼吸速率与土壤温度和湿度有着较好的相关性,土壤温度和湿度共同解释了林地表面土壤呼吸速率的68.10%～98.9%。枯枝落叶层呼吸速率与土壤温度和湿度的相关性较差,土壤温度和湿度共同解释了枯枝落叶层呼吸速率的12.60%～89.80%。根系呼吸速率与土壤温度和湿度的相关性较好,土壤温度和湿度共同解释了根系呼吸速率的55.80%～96.70%。矿质土壤呼吸速率与土壤温度和湿度的相关性较高,土壤温度和湿度共同解释了矿质土壤呼吸速率的40.30%～99.50%。（5）对小兴安岭地区典型针阔混交林择伐后林地土壤呼吸速率年际变化研究结果表明,择伐作业使林地土壤呼吸速率年平均值增加。择伐作业使林地土壤有机质含量发生了变化。林地有机质含量是土壤呼吸速率年平均值变化的主要影响因素,其对林地土壤呼吸速率的影响也将是一个长期的过程。不同采伐强度对林地土壤呼吸速率年均值的影响不同,采伐强度与林地土壤呼吸速率年均值存在显著的二次相关关系。择伐作业造成了林地土壤温度和湿度的变化,土壤温度和湿度成为土壤各组分呼吸速率年平均值变化的主要影响因素。枯枝落叶层呼吸速率年平均值在观测期内逐年增加,使枯枝落叶层成为碳源。枯枝落叶层呼吸速率均值与采伐强度间存在显著的相关关系。在观测期内,中等强度择伐产生较大的枯枝落叶层呼吸速率均值,小强度和较大强度择伐时,枯枝落叶层呼吸速率均值较小。根系呼吸速率年平均值的变化对采伐强度的响应较复杂。根系呼吸速率均值与采伐强度间存在显著的相关关系。在观测期内,较小的择伐强度产生较小的枯枝落叶层呼吸速率均值,小强度、中等强度和较大强度的择伐,产生较大的根系呼吸速率均值。矿质土壤呼吸速率年平均值对采伐强度响应较弱,对林地土壤呼吸速率变化影响不大。更多还原

【Abstract】 Soil respiration is a process of releasing CO₂ from soil.It is composed of three biomass processes（Respiration of soil microbe,respiration of root and respiration of soil animals） and one abiotic process（oxidation of mineral with carbon）.It is one source of CO₂.Forest soil respiration is an important component part of soil respiration in land ecological system,and its change will be a long time effect against globle carbon balance.Forest cutting changed the structure of forest ecological system,or changed the using aim,and will change of the value of CO₂ released.So,to study the effect of forest cutting on soil respiration is very significance.By using LI8100 and by meansing of statistic method,this paper studied the response of soil respiration to soil temperation diurnal change in plantation forest,the sensitivity of soil respiration to soil temperature and moisture after select cutting,the effect of stump in gap on soil respiration rate and the seasonal change and yearly change of soil respiration after select cutting.All above in paper were the first study.The main results were follow:（1） The study result of the diurnal change of soil respiration rate in five type plantation of Betula platyphylla Suk,Juglans mandshurica Maxim,Fraxinus mandshurica Rupr,Pinus sylvestris Linn.Var and Larix gmelini Rupr forest showed that,there was heterogeneity evidently of soil respiration.Soil respiration rate of 5 type plantation forest appeared high value in day and low value in night,and the high value only had one time in measuring date.The response of soil respiration rate of 5 type forest to ground temperature and 10cm depth temperature is not one route.It was appeared hysteresis of the response of soil respiration rate to ground temperature and was appeared advancement of the response of soil respiration rate to 10cm depth temperature.The 10cm depth temperature was the main factor of affect the soil respiration rate.There were two time range of the mean happened in measuring date.（2） The result showed by studing response of soil respiration to soil tempruature and moisture in a conifer-broadleave forest after of select cutting in Xiaoxingan Amount,select cutting were not made the soil tempreture evident difference bue changed the sensitivity of soil respiration to soil temperature.Q₁₀ value were higher in cutting land than that in no cutting land.The response of soil respiration to soil temperature were higher in cutting land than that in no cutting land.This phenomenon was the result of the response of three partitioning respiration to soil temperature.Litter layer respiration had less sensitivity.Root respiration and mineral respiration had higher sensitivity.The more select cutting intensity（60%,71%）,the more sensitivity.Select cutting not made the moisture evident difference.Soil respiration response to soil moisture was not strong.Soil moisture was not the main factor of influence the change of soil respiration rate.（3） The result showed by studing the Effect of Betula platyphylla Suk.plantation forest in gap of Stump on Soil Respiration rate,the effect of stump on soil respiration in gap will be a long time.It effected the value and distribution of soil respiration in gap.The respiration rate of gap soil with stump more than soil respiration rate without stump.Decay degree was the important factor of affecting soil respiration in the gap.The soil respiration rate of stump gap changed from high to low,and then to high about the centre of stump regularly.The max value of spatial heterogeneous grade of soil respiration rate were decrease according to decay index of stump.The max value of the spatial heterogeneity grade were decrease according to the increase of decay degree of stump in the gap with stump.（4） The result showed by studing the season change of soil respiration in a conifer-broadleave forest after select cutting in Xiaoxingan Amount,soil respiration presenced the well season change after select cutting.The soil surface CO₂ flux has good correlated with soil temperature and soil moisture.This two facts could explain 68.10%～98.90%of the variation.Litter CO₂ flux has bad correlated with soil temperature and soil moisture,this two facts could explain 12.60%～89.80%of the variation.Root CO₂ flux and mineral soil CO₂ flux has better correlated with soil temperature and soil moisture,this two facts could explain 12.60%～89.80%and 40.30%～99.50%of the variation.（5） The result showed by studing the yearly change of soil respiration in a conifer-broadleave forest after select cutting in Xiaoxingan Amount,select cutting increased the annual respiration rate.Select cutting made soil organic matter content change.soil organic matter content was the main factor that effect the annual respiration rate change.this will be a long process.Effect were different in different cutting intensity.There was a significant quadratic correlation between the mean soil respiration and cutting intensity.Select cutting made soil temperature and moisure change.Soil temperature and moisure change were two main factors that effectting the annual respiration rate.The annual respiration rate of litter layer soil was increased yearly.This made litter layer as a source of carbon.There was a significant quadratic correlation between the mean soil respiration of litter layer and cutting intensity.During measure time,the select cutting with moderate density made more mean soil respiration of litter layer,and less and large density made less mean soil respiration of litter layer.The annual respiration rate of roots fluctuated. There was a significant correlation between the mean soil respiration of roots and cutting intensity.During measure time,the select cutting with less density made less mean respiration of roots,moderate and large density made large mean respiration of roots. The response of annual respiration of meniral to cutting intensity was no evident.The effect of meniral respiration to annual soil respiration was no significant.更多还原