模拟氮沉降对鹤山3种人工林表土碳释放的影响

为研究大气N沉降对森林表层土壤碳释放的影响,通过室内模拟大气N沉降处理土壤样品,用碱吸收法测定土壤的碳释放量,并计算土壤碳释放速率,分析大气N沉降对鹤山丘陵综合试验站湿地松(Pinus eliotii)、荷木(Schima superba)和马占相思(Acacia mangium)3种人工林土壤碳释放的影响。结果表明,模拟氮沉降对湿地松林表土碳释放过程有非常强的抑制作用,且随着氮处理浓度的升高而加强。低水平的氮沉降对荷木和马占相思林土壤碳释放过程有一定的促进作用,随着沉降水平的升高表现为抑制作用。

Effects of Simulated Nitrogen Deposition on Carbon Release from Three Plantation Soils in Heshan

In order to study the effect of atmospheric nitrogen deposition on the release of carbon from the forest soil,an experiment was done in Heshan Hilly Interdisciplinary Stand.The release rate of CO_2 from 3 forests soils(Pinus eliotii,Schima superba and Acacia mangium)mensured using acid-base titration.The results showed that atmospheric nitrogen deposition depressed the release rate of CO_2 from Pinus eliotii forest soil.Moreover,this effect became stronger with the concentration of nitrogen treatment increasing.Nitrogen deposition accelerated the release rate of CO_2 from Schima superba and Pinus eliotii forest soils when its concentration is low.Nevertheless the release rate from the two forest soils reduced when the concentration of N exceeds the nutritional demands of soil microorganisms.