Effect Of Temperature And Application Levels Of Nitrogen On Soil Water And Nitrogen Transport Characteristics Under Film Hole Irrigation

In this article,on the basis of consulting a large number of domestic and foreign literatures,by means of a combination of experimental and theoretical research,the effects of temperature and nitrogen application rate on soil water and nitrogen transport characteristics under film hole irrigation were studied.The soil water infiltration characteristics and water and nitrogen distribution have analysed and the research conclusions are following:(1)The relationship between the cumulative infiltration volume and the infiltration duration under different experimental treatments were conformed to the Kostiakov and Philip models,there was a very significant power function relationship between migration of the wetting front and the infiltration duration.(2)In the soil one-dimensional vertical infiltration,the migration depth of wetting front(Fv)of fertilizer infiltration were larger than that of water,T was positively correlated with the cumulative infiltration volume(Iv)and Fv.The influence of N on Iv and Fv were less than the infiltration temperature.(3)The increase of T and N during film hole infiltration can promote the migration of soil water,which is manifested by the increase in cumulative infiltration amount(Im)and the migration distance of wetting front of the level(Fmx)and the vertical(Fmz),the volume of the wetted body(θ)increases.During the redistribution process,Fmx and Fmz continued to increase,and θ was more evenly distributed.(4)Under the clear water infiltration,the nitrogen in the wetted body was leached by the water to accumulate near the wetting front with lower moisture content.Under the fertilizer infiltration,the nitrogen in the wetted body was closely related to the distribution of moisture content,with a high θ,the increase of N also increased NO3--N and NH4+-N at the same spatial position.Because NH4+-N and NO3--N have different charges,the distribution of nitrogen in the wetted body was different.The wetted body nitrogen distribution was quite different among N=5000 mg·L-1 and others,it may be with a too large N,the water content influenced the nitrogen content far greater than the ratio of solute transport.T influenced water infiltration and makes nitrogen distribution different.At the same time,the temperature of soil pores also affects solute transport parameters and a small amount of nitrogen conversion.As T increasing,the nitrogen content in the same space in the wetted body increased,and NH4+-N was more significantly affected by T.(5)Laboratory experiments analyze the different treatment effects on soil water and nitrogen transport characteristics.The results show that:Im,Fmx,Fmz were positively correlated with T and N;average volumetric water content increase of the wetted body(Δθ)was positively correlated with T but negatively correlated with N.The influence of T on Im was less than N,while the influence of T on Fmx,Fmz and Δθ was greater than N.Establish and verify the regression equations between test indicators(Im,Fmx,Fmz,Δθ)and influencing factors(N,T,t).The models had a good simulation effect and can be used to predict the test indicators of different test factors.