Water and nitrogen transport characteristics of single-line interference infiltration under film hole irrigation with muddy water and fertilizer

Based on the experimental data, this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation with muddy water and fertilizer. The relationship between the single-line interference infiltration parameters, the sand content, the wetting front movement distances, and the sand content were all established. The model of the cumulative infiltration volume of per unit film pore area, the vertical and horizontal wetting front movement distance of the free surface, and the wetting front movement distance of the interference center with sand content and infiltration time were proposed. Reveal the law of the change of soil water content and the distribution of NO~--N content based on different muddy water sand content. The results indicate that at the same infiltration time, as the muddy water sand content increases, the cumulative infiltration volume per unit pore area decreases. The infiltration index of the free infiltration and the single-line interference vary little when the sand content increases, mainly are around 0.64 and 0.58. The relationship between infiltration parameters a, b and the sand content is linear function. At the same location, the more the sand content, the smaller the wetting front movement distance in free surface and the single-line interference surface, the less the NO~--N content.