摘要
外源氮输入影响森林土壤理化性质的稳定性,进而影响其CO2通量.本研究以寒温带兴安落叶松林土壤为研究对象,设置3个氮输入水平(低氮N1 10kg/hm2、中氮N2 20kg/hm2、高氮N3 30 kg/hm2)和对照组(CK).于5月-9月采用静态箱-气相色谱法测定土壤CO2通量,建立通径方程,分析土壤TS10、MS10、TN、NH4+-N和NO3--N与土壤CO2通量的关系,阐明外源氮输入对寒温带兴安落叶松林土壤CO2通量的影响.结果表明:①土壤TS10、MS10、TN、NH4+-N和NO3--N含量的均呈现先升高后降低的趋势,土壤NO3--N含量整体呈现下降趋势;随氮输入水平增加,TS10、TN、NH4+-N和NO3--N含量逐渐升高,MS10逐渐降低.②土壤CO2通量随季节变化呈明显的单峰变化特征,峰值出现在8月;适量的氮输入可显著提升土壤CO2通量,反之则会抑制土壤CO2排放.③对照组土壤CO2通量均与土壤TS10、MS10呈极显著正相关关系;不同氮输入水平土壤CO2通量均与土壤TN和NH4+-N含量密切相关,与土壤NO3--N含量不相关.
Abstract
Exogenous nitrogen input affects the stability of physical and chemical properties of the forest soil,which in turn affects its CO2 flux.Three nitrogen input levels,i.e.,low nitrogen N1(10 kg/hm2),medium nitrogen N2(20kg/hm2),high nitrogen N3(30kg/hm2),and control group(CK),were set in the soil of Larix gmelinii forests in the cold temperate zone.Static chamber-gas chromatography method was used to measure the soil CO2 flux from May to September,and the path equation was established to analyze the relation-ship between soil TS10,MS10,TN,NH4+-N and NO3--N,and soil CO2 flux.The influence of exogenous nitrogen input on the soil CO2 flux in the Larix gmelinii forests was clarified.The results showed that,the contents of soil TS10,MS10,TN,NH4+-N and NO3--N in-creased first and then decreased,and the soil NO3--N content showed an overall decreasing trend.With the nitrogen input level in-creasing,the contents of TS10、TN、NH4+-N and NO3--N gradually increased,while MS10 gradually decreased.The soil CO2 flux showed a significant unimodal variation with seasonal variations,with the peak occurring in August.Appropriate nitrogen input could significantly increase the soil CO2 flux,and vice versa,inhibit soil CO2 emission.The CO2 flux in the control group soil was positively correlated with soil TS10 and MS10.The soil CO2 fluxes at different nitrogen input levels were closely related to the soil TN and NH4+-N content,but not to the soil NO3--N content.
基金项目
内蒙古科技计划项目(2023KYPT0001)
内蒙古科技计划项目(2023YFDZ0026)
国家重大研发计划项目(2023YFF1304002)
万方数据