外源添加对黄河流域典型湿地土壤矿化及硝化的影响

Effects of exogenous addition on soil mineralization and nitrification of typical wetlands in the Yellow River Basin

以黄河上游若尔盖湿地(A土)、中游包头南海湿地(B土)、下游黄河三角洲湿地(C土)为研究对象,分别选用NH4NO3和葡萄糖作为外加氮源和碳源,采用28d恒温培养法,研究了外源添加对黄河流域典型湿地土壤日平均碳矿化速率(Caverage)、净氮矿化速率(NNmin)、净硝化速率(NNnitri)的影响。结果表明,湿地类型对土壤碳、氮矿化及硝化速率影响显著,土壤理化性质差异是主要影响因素。外源碳添加对不同类型湿地Caverage均显著提高,且对A土促进作用最显著;外源氮添加对Caverage影响不显著。外源碳、氮添加水平对不同类型湿地NNmin的影响存在显著差异。低水平碳源添加显著抑制C土NNmin,但对A土和B土NNmin影响不显著;高水平碳源添加对不同类型湿地NNmin均表现出显著的抑制作用。低水平氮源添加对不同类型湿地NNmin影响不显著;高氮添加显著抑制B土、C土NNmin,但对A土NNmin影响不显著。外源碳、氮添加对不同类型湿地NNnitri的影响不显著。

Taking Zoige Wetland(soil A)in the upper reaches of the Yellow River,Baotou Nanhai Wetland(soil B)in the middle reaches,and the Yellow River Delta Wetland(soil C)in the lower reaches as the research objects,NH4NO3 and glucose were used as external nitrogen and carbon sources,respectively,and a 28 d constant temperature cultivation method was used.The effects of exogenous addition on daily average carbon mineralization rate(Caverage),net nitrogen mineralization rate(NNmin),and net nitrification rate(NNnitri)of typical wetland soil in the Yellow River Basin were studied.The results show that wetland types have significant effects on soil carbon and nitrogen mineralization and nitrification rates,and differences in soil physical and chemical properties are the main influencing factors.Carbon addition significantly increased Caverage of different wetland soils and the most significant promotion was exerted on soil A.However,nitrogen addition had no significant effect on Caverage.Addition level had significant influence on NNmin.Low level carbon addition significantly inhibited NNmin of soil C while had no significant effect on that of soil A or soil B.High level carbon addition significantly prevented NNmin of different wetland soils.Low level nitrogen addition had no significant effect on NNmin.High level nitrogen addition significantly inhibited NNmin of soil B and soil C,while had no significant effect on soil A.Exogenous addition had no significant effect on NNnitri.