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Xi’an University of Technology (2021)

Study on the Soil Water-nitrogen Transport and Transformation Characteristics and Crop Coupling Effects

陈琳

Titre : Study on the Soil Water-nitrogen Transport and Transformation Characteristics and Crop Coupling Effects

Auteur : 陈琳

Grade : Doctoral Dissertation 2021

Université : Xi’an University of Technology

Résumé partiel
On the basis of consulting the relevant literature at home and abroad,combining with the National Nature Fund project,and in view of the shortage of water resources,the natural conditions of farmland and the characteristics of the film-hole irrigation in arid areas of China,adopting the technical route of combining experiment,theoretical research and numerical simulation.In this dissertation,the nitrogen transfer and transformation characteristics of film-hole infiltration with fertilizer solution in layered soil,the characteristics of the soil with γ-polyglutamic acid vertical infiltration and its influencing factors,the characteristics of the soil with γ-polyglutamic acid infiltration under the film-hole irrigation and its influencing factors,the effects of γ-polyglutamic acid on spinach growth and soil structure,and the coupling effects of water-nitrogen on Winter Wheat under the film-hole irrigation have been studied.The main research results are as follows,(1)The effects of sand layer position on soil water and nitrogen transport and transformation characteristics of free infiltration under the film-hole irrigation with fertilizer solution in layered soil has been studied.Using HYDRUS-3D model to simulate soil water and nitrogen transport and transformation under the film-hole free infiltration.The cumulative infiltration of the film-hole irrigation was obviously affected by sand layer.The infiltration capacity increased with the increase of the buried depth of sand layer.The wetting front appeared obvious discontinuity at the loam-sand interface.The infiltration capacity of film-hole increased with the increase of the buried depth of the sand layer.The wetting front had an obvious discontinuity at the soil-sand junction.As the buried depth of the sand layer increased,the shape of the wetting front tended to be semi-ellipsoid.At the end of the infiltration,the sand layer caused the urea nitrogen to be mainly distributed in the upper silt loam,and decreased in the direction away from the center of the film-hole gradually.There were three areas,such as high concentration area,high gradient area and low concentration area.During the redistribution phase,the urea nitrogen content showed a decreasing trend due to the hydrolysis reaction ;The ammonium nitrogen content in the soil near the center of the film-hole was larger than that at the wetting front,and gradually decreased in the direction away from the center of the film-hole ;Ammonium nitrogen was concentrated in the soil layer above the sand layer,and the content at the soil-sand interface increased significantly ;The soil nitrate nitrogen content at the same location increased with time increase ;The soil nitrate nitrogen content at the horizontal wetting front increased faster than that near the center of the film-hole,and was larger at the soil-sand interface ;the front migration distance of the redistributed concentration of soil nitrate nitrogen increased with the increase of the buried depth of the sand layer.(2)The effects of applying y-polyglutamic acid on soil water characteristic parameters,soil infiltration characteristics,and soil water holding capacity were studied

Mots clés : Film-hole irrigation ;γ-polyglutamic acid ;The transport and transformation of water and nitrogen ;The water and nitrogen coupling ;HYDRUS model ;

Présentation (CNKI)

Page publiée le 15 novembre 2021