The Effect Of Native Mycorrhizal And Intercropping On Nitrogen Loss And Reduction Mechanism On Purple Soil Surface

Agricultural non point source pollution had become one of the main causes of eutrophication in recent.AMF technology was the agricultural non-point source pollution control technology which had advantages and development prospects,intercropping also had significant contribution for the prevention and control of non-point source pollution.This study included artificial and natural simulated rainfall experiments.Each experiment had runoff simulation and leaching simulation.In this study,plant growth and nitrogen(N)utilization of maize(Zea mays L.)intercropping with soybean or monocropping in purple soils were investigated through different N application treatments and different AMF treatments.Two mycorrhizal treatments [ none mycorrhizal inhibition(NMI),mycorrhizal inhibition(MI)] and three N treatment ways [none N addition(N0),ammonium bicarbonate application(N1)and urea application(N2)] were set up.The objective of this research was to investigate the influence of the MI treatment and intercropping systems on reduction of N transport on purple soil under N application conditions.The study explored the reduction mechanism of the influence factors on N loss on surface runoff and in leakage.The objective of this research was to provide the theoretical foundation and application for the study of nitrogen control in the south slope farmland.Result showed as follow:(1)Comparing with the monocropping and NMI treatment,the treatment of NMI and intercropping significantly increased plant biomass of the root,stem and leaf.Artificial simulated rainfall experiment showed that the largest plant biomass of root,stem and leaf were found for the NMI-N2 intercropping maize treatment.Under the same N treatment and planting mode,plant root,stem and leaf,N concentration and N uptake of thr NMI treatment was obviously higher than the MI treatment.Under the same planting mode and N treatment,N uptake efficiency of maize and soybean for NMI treatment was higher than the MI treatments.(2)For artificial simulated rainfall experiment,NMI-intercropping treatment respectively decreased the concentration of the total N,soluble N,ammonia N,and nitrate N in runoff and leakage water.Natural simulated rainfall experiment showed that,the NMI-N1 intercropping treatment had the lowest N concentration in runoff and leakage water among all the treatments.Under the same N treatment and slope,nitrate N?soluble N ?ammonium N?and particulate N,N concentration of the monocropping treatment was obviously higher than the intercropping treatment.In short,with the passage of rain time,N loss decreased first and then increased,and then decreased,the final trend of steady.(3)Regardless of the N treatment,the treatment of NMI treatment,intercropping improved the hyphal density and GRSP content in soil,and increased water stable aggregates(2~0.25 mm?>2 mm)content and reduced soil micro-aggregate content in soil.Natural simulated rainfall experiment showed that,the complex treatment of NMI-N1 under intercropping soybean condition,was the best one for increasing the content of 2~0.25 mm water stable aggregates(48.58%).For artificial simulated rainfall experiment,the complex treatment of NMI-N2-intercropping soybeanwas the best one for improving the content of 2~0.25 mm water stable aggregates(51.63%).(4)There were negative correlation between(2~0.25 mm ? >2 mm)water stable aggregates in soil and nitrogen in runoff and leakage water.There were also negative correlation between GRSP and nitrogen in runoff and leakage water.There were negative correlation between ammonium and nitrate in siol and nitrogen in runoff and leakage water..