| The population density in the Wangbeng area of the Huaihe River Basin is huge.It is an important food production area in China and has a pivotal position in China’s agricultural production.The excessive use of chemical fertilizers makes the problem of agricultural non-point source pollution not to be underestimated.In this study,nitrogen transmission in the Wangbeng section of the Huai River Basin was designed as the research object,and the field simulation experiment plot was designed,and the leaching rate and rainfall experiment under different fertilizer application methods and different straw returning methods were simulated,from the vertical and horizontal directions.Exploring the process of nitrogen transmission from agricultural sources in the Wang-Cang section of the Huai River Basin from a perspective,and jointly exploring the characteristics of nitrogen transmission in the Huai River Basin,the results are as follows:(1)Soil moisture content and NH4+-N,NO3--N and TN concentrations were significantly different among the upper,middle and lower reaches,but there was no significant difference in soil pH value.HFO,JF10,JF30 and CK had significant effects on DOC,NH4+-N,TN,water content and pH,while HFO had no significant effect on NO3--N.Straw combined with chemical fertilizer could effectively increase the NO3--N content in the soil.Under JG0 treatment,the accumulations of nitrogen and DOC were lower,while under JG10 treatment,the accumulations of DOC,TN and water content were higher,and under JG20 treatment,the accumulations of nitrogen and DOC were not obvious.The best condition for straw returning to the field was to bury 10cm of straw.(2)During the leaching experiment,the loss of nitrogen in the soil flow mainly occurred in the early and middle stages,and the loss of nitrogen in the leaching solution mainly occurred in the early stage.Most of the leaching forms of nitrogen leached out in the form of dissolved inorganic nitrogen.The loss ratio fluctuates between 33%and 56%.Under the same precipitation,the NH4+-N leaching loss of the single fertilizer group is mainly in the form of longitudinal migration,and NO3--N is mainly leached in the form of lateral migration.The combined application of chemical fertilizer and straw significantly increases the leaching ratio of NH4+-N.The ratio of NO3--N and TDN leaching loss is reduced,and the depth of straw returning to the field has the greatest impact on the nitrogen leaching loss in the early stage,and has less impact on the middle and late leaching loss.(3)Under the same rainfall conditions,the combined application of chemical fertilizers and straws reduced the nitrogen loss load in the soil and soil.The nitrogen loss was mainly caused by the soil flow.The soil dissolved nitrogen loss load was mainly affected by NO3--N,and the inorganic nitrogen was mainly affected by NO3--N.The form of NO3--N occurs,and the depth of straw landfill has no significant effect on the loss of TN,TDN,and NH4+-N loads.When the rainfall intensity is the same,there is a significant positive correlation between the loss of surface flow TN and the loss of TDN,NH4+-N,and NO3--N,and the loss of TN in the soil flow is significantly positively correlated with the loss of NO3--N.The combined application of straw can effectively reduce the nitrogen loss concentration in surface runoff and increase the average loss concentration of NO3+-N in the soil,but has no significant effect on the loss concentration of NH4+-N,TN,and TDN.In addition,the depth of landfill has an effect on TN,TDN,and TDN.NH4+-N load loss has no significant effect.Fig.[62]Table[21]Reference[97]... |
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