Zhou Xue Ya, Chen Zhi Jie, Geng Shi Cong, Zhang Jun Hui, Han Shi Jie
Ministry of Education Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Kaifeng 475001, Henan, China.
Tan Kah Kee College, Xiamen University, Zhangzhou 363105, Fujian, China.
Ying Yong Sheng Tai Xue Bao. 2019 May;30(5):1543-1552. doi: 10.13287/j.1001-9332.201905.025.
Nitrogen deposition is one of the most important factors affecting carbon (C) and nitrogen (N) cycling in terrestrial ecosystem. A six-year N addition experiment was carried out to explore how N deposition affected C and N fractions in soil aggregates in the secondary aspen forest (YHL) and primary Korean pine broad-leaved forest (HSL). We investigagted the effects of N addition on dissolved organic carbon and nitrogen (DOC and DON), microbial biomass carbon and nitrogen (MBC and MBN), particulate organic carbon and nitrogen (POC and PON) in soil aggregates with different particle sizes. The results showed that the contents of carbon and nitrogen fractions generally increased with the decrease of particle sizes of soil aggregates except for POC and PON. In soil aggregates of HSL, POC and PON significantly decreased by 20.7% and 22.6% in N treatment, respectively, but DOC increased by 11.6%. In YHL, N addition treatment had no signi-ficant effect on C and N fractions in soil aggregates. Total carbon or nitrogen correlated well with the active C and N fractions in soil aggregates, with a great significant negative correlation between POC and DOC in HSL (r=-0.503) and a significant positive correlation between DOC and MBC (r=0.462). In HSL, the negative effect of N treatment on POC and PON and the positive effect on DOC was mainly attributed to the accelerated decomposition of POM by stimulating microbial activity. Soil C and N pools in HSL were more vulnerable to N deposition than that in YHL.
氮沉降是影响陆地生态系统碳（C）和氮（N）循环的最重要因素之一。开展了一项为期六年的氮添加实验，以探究氮沉降如何影响次生白杨林（YHL）和原始红松阔叶林（HSL）土壤团聚体中的碳和氮组分。我们研究了氮添加对不同粒径土壤团聚体中溶解有机碳和氮（DOC和DON）、微生物生物量碳和氮（MBC和MBN）、颗粒有机碳和氮（POC和PON）的影响。结果表明，除POC和PON外，碳和氮组分的含量一般随土壤团聚体粒径的减小而增加。在HSL的土壤团聚体中，氮处理下POC和PON分别显著下降了20.7%和22.6%，但DOC增加了11.6%。在YHL中，氮添加处理对土壤团聚体中的碳和氮组分没有显著影响。土壤总碳或总氮与土壤团聚体中的活性碳和氮组分相关性良好，在HSL中POC和DOC之间存在极显著负相关（r = -0.503），DOC和MBC之间存在显著正相关（r = 0.462）。在HSL中，氮处理对POC和PON的负面影响以及对DOC的正面影响主要归因于通过刺激微生物活性加速了颗粒有机物质（POM）的分解。HSL中的土壤碳和氮库比YHL中的更容易受到氮沉降的影响。
