东北人工红松针叶林和天然次生阔叶混交林林下土壤氮初级转化速率特征  

Characteristics of Gross Nitrogen Transformation Rates in the Soils of Pinus koraienis Coniferous Plantations and Natural Secondary Broad-leaved Mixed Forests in Northeast China

作　　者：郎漫[1,2] 吴昌福 苏孝纯 李平[1,2] LANG Man;WU Chang-fu;SU Xiao-chun;LI Ping(Jiangsu Key Laboratory of Agricultural Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China;School of Applied Meteorology,Nanjing University of Information Science&Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南京信息工程大学,江苏省农业气象重点实验室,江苏南京210044 [2]南京信息工程大学应用气象学院,江苏南京210044

出　　处：《林业科学研究》2022年第3期63-71,共9页Forest Research

基　　金：国家自然科学基金项目(41301345,41101284)。

摘　　要：[目的]为了解森林土壤氮素转化特征及土壤氮供应能力,为森林生态系统合理经营管理提供科学依据。[方法]以东北寒温带人工红松针叶林和天然次生阔叶混交林表层土壤为研究对象开展室内培养试验,采用^(15)N同位素成对标记技术和FLUAZ数值优化模型,研究不同深度的土壤氮初级转化速率特征。[结果]林地土壤的氮初级转化速率受林型、土壤深度及二者间交互作用的影响。人工红松针叶林土壤氮初级矿化速率和无机氮固定速率显著低于天然次生阔叶混交林土壤,而初级硝化速率显著高于天然次生阔叶混交林土壤,2个林型土壤的氮初级转化速率都随着土壤深度的增加显著降低。土壤氮初级矿化速率和固定速率与土壤pH、有机碳、水溶性有机碳与水溶性有机氮含量呈显著正相关,土壤初级硝化速率与土壤pH呈显著负相关。人工红松针叶林土壤初级硝化速率与铵态氮固定速率比值显著高于天然次生阔叶混交林土壤,而对硝态氮的固定速率显著低于天然次生阔叶混交林土壤。[结论]2种林型土壤氮素转化特征差异明显,人工红松针叶林土壤的硝态氮产生能力较强而无机氮固持能力较弱,容易发生硝态氮的淋溶风险,天然次生阔叶混交林土壤氮矿化-固定过程耦合较好且硝化作用较弱,不易引发硝态氮的积累和淋溶风险。[Objective]To understand the characteristics of nitrogen(N)transformation and N supply capacity of forest soils,and provide scientific basis for the rational management of forest ecosystem.[Method]In this study,two surface soils of Pinus koraienis coniferous plantations and natural secondary broad-leaved mixed forests were selected in cold temperate zone in Northeast China.The characteristics of gross N transformation rates in different soil depths were investigated through a laboratory incubation experiment using the ^(15)N paired tracing technique and numeric FLUAZ model.[Result]Gross N transformation rates in forest soils were affected by forest type,soil depth,and their interactions.Gross N mineralization and immobilization rates in the soil of Pinus koraienis were significantly lower than those in natural secondary broad-leaved mixed forest,while gross nitrification rate was significantly higher than that in natural secondary broad-leaved mixed forest.Soil gross N transformation rates under the two forest types decreased significantly with increasing soil depth.Soil gross N mineralization and immobilization rates were significantly positively correlated with soil pH,contents of soil organic carbon(SOC),water soluble organic carbon(SOCw),and water-soluble organic nitrogen(SONw),whereas soil gross nitrification rates were significantly negatively correlated with soil pH.The ratio of gross nitrification rate to NH_(4)^(+) immobilization rate in the soil of Pinus koraienis plantations was significantly higher than that in natural secondary broad-leaved mixed forests,but the immobilization rate of NO_(3)−was significantly lower than that in natural secondary broad-leaved mixed forests.[Conclusion]The characteristics of soil N transformation between the two forest types are significantly different.Compared with natural secondary broad-leaved mixed forests,Pinus koraienis plantation soil has stronger NO_(3)−production capacity and weaker inorganic N retention capacity,resulting in higher risk of NO_(3)−leachi

关 键 词：^(15)N标记 氮初级转化速率 人工红松针叶林 次生阔叶混交林 

分 类 号：S153[农业科学—土壤学]