【作者】 孔雨光；

【导师】 张金池；

【作者基本信息】 南京林业大学 ， 生态学， 2009， 博士

【摘要】 文章选取苏北淤泥质海岸典型的杨树及水杉林分进行了土壤呼吸研究,同时研究了与土壤呼吸密切相关的土壤微生物量碳和对土壤有机质起物理保护作用的团聚体及结合有机碳。结果表明:（1）杨树及水杉林地土壤呼吸均有明显的季节动态变化,暖季土壤呼吸速率比冷季大。土壤呼吸的季节性变异主要受土壤温度的控制,水杉林地土壤呼吸对温度的敏感性大于杨树林地。土壤含水量不是两种林地土壤呼吸的限制性因子。（2）杨树和水杉林地根系呼吸的年通量分别为767.5gm^-2和902.8gm^-2,两林地根呼吸对土壤总呼吸的贡献率分别为20.2%与25.0%。（3）杨树与水杉林地土壤碳矿化速率均随温度的升高而增大。低含水量时,含水量增加会导致土壤碳矿化速率骤然变大,而后随含水量的逐渐增加,增加幅度减小,根据我们的实验结果（可以推测）,含水量超过某一临界值后将导致土壤碳矿化速率的降低。（4）土壤微生物量碳含量随土壤深度的增加而降低,和土壤有机碳、C:N比及全N存在着显著正相关,和土壤pH值及容重存在着负相关关系。与土壤有机碳的相关性最高,表明土壤有机碳是影响土壤微生物量碳的最主要因素。更多还原

【Abstract】 There is large area of coastal shelter forests in China and few studies had been carried out on their effects as net carbon sink or source to the atmosphere.As one of the most important part of the carbon cycle,therefore,the study of soil respiration had great sense.Two typical shelter forests,the poplar plantation and water fir plantation,had been chosen to study the soil respiration in silting coast,northern Jiangsu Province.At the same time,soil microbial biomass carbon and aggregate-associated organic carbon that were tightly correlated with soil respiration had been studied.The results showed that:（1） The annual soi CO₂ efflux was 3792.2gm^-2 and 3610.2gm^-2 for the poplar and water fir plantation respectively.The soil respiration of both two plantations had significantly seasonal dynamics,which were greater in warmer months and less in cold months.And they were both mainly controlled by temperature,and less controlled by the soil water content.The soil respiration of water fir plantation had greater sensitivity to temperature than poplar plantation.（2） Both of the two components,the root respiration and the heterotrophic respiration,had the similar seasonal dynamics as the total soil respiration.The annual root respiration efflux was 767.5gm^-2 and 902.8gm^-2 for the poplar and water fir plantation,respectively.The contribution of root respiration to the total was 20.2%and 25.0%for poplar plantation and water fir plantation, respectively.Therefore,the contribution of the heterotrophic portion contributed more to the total than the root respiration.They were 3.9 and 3.0 times as large as the root respiration contribution for the Poplar plantation and Water fir plantation,respectively.（3） The results of the simulated soil mineralization experiments showed that the mineralization of the soil sampled from both plantations can be accelerated by temperature increase.Water content also had effects on soil mineralization rate:when it was at low level,its rose would increase the mineralization rate abruptly;when it was at higher,its rose would slightly increase the mineralization rate,and we could conclude with our results that when it was bigger than a critical value,its rose would decrease the mineralization rate.（4） Soil microbial biomass carbon decreased with the soil depth.And it was significantly correlated positively with SOC,C:N ratio and total N content and negatively with pH and soil bulk density.And it was more correlated with SOC content than other factors,which indicated that the soil microbial biomass carbon content was mostly depended on SOC content.更多还原