The Influence Of Cu And Ni Amendment On Potential Nitrification Rate For 17 Areas Of Chinese Agricultural Soils

Soil heavy metal contamination concerns both animals and human health, and has been a worldwide problem in recent yeats.Due to the sensitivity of some soil microorganisms to heavy metal contamination,they have been utilised as biomarkers for the adverse effects of heavy metal contamination in soil. Nitrification had became one of most significant factors to estimate soil heavy metal pollution for its sensitivity to heavy metal toxicity and key role in global N-cycle.Now,the biogeocenose-Biotic Ligand Model has been studied in Europe,turned out that the Biotic Ligand Model of forecasting biology. acute-toxicity to soil heavy metals is feasible.And we also have make the great success in liquid Biotic Ligand Model in China.In this paper,the effects of Cu and Ni on nitrification rate in agricultural soils were studied,which were sampled from 17 different areas of China.The results were that:(1)Along with the increase of Cu concentration,the potential nitrification rate dropped in unleached and leached agricultural soils.The EC50 value in unleached agricultural soils was 73.4 mg·kg^-1-2164.4 mg·kg^-1(as measured by Cu concentration),which was remarkably positively correlated with soil pH,Mg, and Ca,respectively.A negative correlation was found between PNR₀ and Clay (<2μm),Al,individually.However,PNR₀ had a positive correlation with soil pH and no relationship with CEC.But for leached soils,the EC50 values distributed between 73.4 mg·kg^-1-2164.4 mg·kg^-1,PNR₀ was remarkably negatively correlated with Clay(<2μm)and Al,but had a positive correlation with pH.(2)Along with the increase of Ni concentration,the potential nitrification rate dropped in unleached and leached agricultural soils,the EC50 value in unleached agricultural soils was 69.7 mg·kg^-1-2330 mg·kg_¹(as measured by Ni concentration),which was remarkably positively correlated with soil pH and Ca respectively.PNR₀ was negatively correlated with Clay(<2μm)and Al,but positively correlated with pH and Ca.However in leached soils,the EC50 value was 32.0 mg·kg^-1-2372 mg·kg^-1,and PNR₀ had the negative correlation with Clay,Fe and Al,but had the positive correlation with pH and Ca.(3)About Cu or Ni,the toxicity of leached agricultural soils is receded to unleached agricultural soils.The result was the foundation for establishing BLM.Furthermore,our research had founded an experimental method to monitoring agricultural soil pollution in China.