Abstract: By using RETC and SWMS-3D software, the point source infiltration characteristics of several typical soils under film hole irrigation were simulated, with the infiltration characteristics and related affecting factors analyzed. One simplified point source infiltration model with the parameters opening film hole rate, film hole diameter, soil clay particle content, and soil bulk density was established, and tested by infiltration experiments with the typical soils from Loess Plateau. It was shown that the infiltration coefficient under film hole irrigation increased with increasing opening film hole rate and decreased with increasing film hole diameter and soil clay particle content, while the infiltration index decreased with increasing opening film hole rate and soil clay particle content. This model could simply and accurately reflect the point source infiltration characteristics under film hole irrigation, and credibly determine the infiltration coefficient and index.

Key words: film hole irrigation, simplified model, clay particle content, soil bulk density, numerical simulation, intensity of fertilization, proportion of NPK, environmental safety threshold, environmental risk assessment.