Laboratory experimental study on effects of fertilizer solution concentration on transport characteristics of NO^-₃-N under single film hole infiltration

Based on indoor experiment, NO^-₃-N concentration distribution characteristics under single point source infiltration with different fertilizer solution concentrations were studied. The wetting front distance of NO^-₃-N concentration under film hole infiltration has the same pattern as the movement of soil wetting front. The concentration front distance of NO^-₃-N and the maximum value of NO^-₃-N concentration in soil profile increase with the increase of the solution concentration at the same time. The NO^-₃-N concentration increases with the increase of the solution concentration at the same depth. The NO^-₃-N concentration distribution characteristics and wetting frong depth under fertilizer solution infiltration satisfy the subsection function model. The concentration front distance of NO^-₃-N and the maximum value of NO^-₃-N concentration increase with the increase of the time in the process of water supply. The concentration front distance of NO^-₃-N increases with the increase of the time in the process of redistribution and the maximum value of NO^-₃-N concentration decreases.