Research On The Nitrification And Influencing Factors Of Different Fluvo-aquic Soil Fertility

?Objective?On the basis of a long-term fluvo-aquic soil fertilization experiment in Zhengzhou city of Henan Province,this paper studies the soil nitrification potential of different fertility and its main influencing factors.?Methods?Three different types of soil were collected and sampled,including high fertility soil?combinative application of organic and inorganic fertilizer?,moderate fertility soil?balanced application of fertilizer?and low fertility soil?applied with no fertilizer or no nitrogen fertilizer?;soil nitrification potential,total nitrogen?TN?,ammonium nitrogen?NH₄⁺-N?,nitrate nitrogen?NO₃^--N?,microbial biomass carbon?MBC?and microbial biomass nitrogen?MBN?are analyzed by using modern statistical analysis methods,such as stepwise regression analysis,path analysis and variance decomposition analysis?VDA?,through which,the main influencing factors of the soil nitrification potential with different fertility is exacted defined and also clear,and the contribution of each main influencing factor to soil nitrification potential si quantified as well.?Results?It has been demonstrated that nitrification potential of the fluvo-aquic soils differs from each other dramatically within the range of 0.3 mg kg^-11 h^-11.1 mg kg^-1h^-1.From the research,we can see,on average,the nitrification potential of high fertility soil was 7.9%higher than the nitrification potential of moderate fertility soil,and the nitrification potential of moderate fertility soil was 162.5%higher than the nitrification potential of low fertility soil.Among all the soil fertility indicators,MBC,NO₃^--N,TN and MBN were found to be the main influencing factors of soil nitrification potential.Among them,MBC,NO₃^--N and MBN are proved to be direct influences while indirect influences of TN and soil nitrification potential are turned out to be indirect influences,which are stronger than direct influences.The contribution rates of microbial biomass?MBC and MBN?,NO₃^--N and TN to soil nitrification potential variations were 24.3%,18.9%and 13.7%respectively.The contribution of four main influencing factors'interaction effects to the variation of soil nitrification potential has reached to 52.8%,while the total contribution of each variant and its interaction effects amounted to 92.9%.Therefore,it can be concluded that nitrification of high fertility soil with long-term combinative application of organic and inorganic fertilizer is much stronger in soils of high fertility than in soils of low and moderate fertility.?Conclusion?From the study,it is obviously clear that nitrification is stronger in high fertility soil with long-term organic and inorganic fertilizer combination,and ammonium nitrogen could be easily nitrified into nitrate nitrogen,while the latter one is more likely to be accumulated and leached.So,it is necessary to improve the condition of soil moisture in the land,reduce nutrient regimes to a proper level and control the formation and accumulation of nitrate nitrogen so as to achieve the purposes of constructing a nitrogen nutrient pool and reducing nitrogen loss in fluvo-aquic soils.