Investigation On Water And Nitrogen Transport In Saline Soil As Affected By Groundwater Shallow Through Drip Irrigation From A Point Source

This research was fully summarizing and inheriting senior's research results and in the advanced experience foundation, unified the characteristic this topic and the request, in the use room the micro salty water drip irrigation experiment, emphatically observed the subsoil water level differently to influence which distributed in the soil for soil water and nitrate concentration under the drip irrigation condition, provided the reference for salt alkaloid as well as developing the underground micro salty water。The subsoil water level respectively is 20, 40, 60, 80, 100cm ,observing the nitrogen migration and distribution under the drip irrigation condition . In the experiments, the application rate was 0.0315 (L/h), the input concentration was 1g/L and the applied volume was 334334ml. The experimental result indicated that:(1)Before the drip irrigation experiment, each processing volumetric water content assumed the layered distribution, increasing in turn from the surface layer to the ground water potential surface soil moisture content.(2) Under the drip irrigation conditions , the saturated wetted radius on the surface,the vertical wetted distance and the horizontal wetted radius for different subsoil water level increased along with the drop of the subsoil water level depth; horizontal and vertical wetted distance assumed the power function relations along with the drip irrigation time increase to increase, but the vertical direction wetted distance increase is more obvious than the horizontal direction; Irrigated when the conclusion, the soil water distribution scope increased along with the descent of the subsoil water level.(3) Before the drip irrigation experiment, the surface layer soil nitrate concentration is highest, also gradually decreased from the surface layer soil to the ground water potential surface .(4)Irrigated when the conclusion, nitrate accumulated the moist front, is apart from in the drop 17.5cm scope the even distribution, in this scope nitrate average density is smaller than in front of the drip irrigation nitrate density, also the average density reduced slightly along with the descent of subsoil water level; nitrate concentration distribution rule and the subsoil water level not obviously to relate.