氮添加对人工油松林土壤碳组分的影响

Effect of Nitrogen Addition on Soil Carbon Components in Planted Pinus tabulaeformis Carr. Forest

为分析氮沉降对土壤碳库组成及其稳定性的影响,选取了黄土高原植被恢复中的树种油松(Pinus tabuliformis Carr.)作为研究对象,通过氮添加模拟氮沉降,分析了短期氮添加对土壤有机碳(SOC)及其不同活性组分变化规律的影响,结果表明:随着氮添加含量的增大,上层土壤SOC及其高活性组分(C_1)、中活性组分(C_2)和稳定性组分(C_4)含量先增加后降低,在N_3达到最大值,对下层土壤SOC及其组分影响较小。氮添加对不同碳组分在总有机碳中的分配比例和土壤碳库活性系数影响较少,4个组分中C_4所占比例最大,达74.3%~87.3%。本研究从土壤碳库稳定性角度分析了氮添加对黄土丘陵区森林土壤的碳库组成的影响,有利于对未来全球变化下的土壤碳库过程影响的认识。

In order to analyze the effect of nitrogen deposition on the composition and stability of soil carbon pool,Pinus tabuliformis Carr.was selected as the research object in this study.Nitrogen addition simulating nitrogen deposition was used to analyze the effects of short-term nitrogen deposition.The results showed that the SOC,the high activity component（C1）,the middle activity component（C2）in the upper soil increased with the increase of the nitrogen contents,and the content of stability component（C4）firstly increased and then decreased,reaching to the maximum value at N3,and had little effect on the SOC and its components of the deep soil.Nitrogen addition has little effect on the distribution ratio of different carbon components in total organic carbon and the activity coefficient of soil carbon pool,and C4 has the largest proportion among the four components,reaching to 74.3%-87.3%.From the point of view of the stability of soil carbon pool,this study analyzed the effect of nitrogen addition on the carbon pool composition in the forest soils in the loess hilly region,which is conducive to the understanding of the impact of future global changes on soil carbon pool processes.