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【Objective】 Water infiltration in soil is an important process for designing drip irrigation and is impacted by soil properties. The purpose of this paper is to investigate the effect of soil hydraulic properties on water infiltration from a single-point source in membrane-hole irrigation. 【Method】 The studies were based on the HYDRUS-2D software, with the soil hydraulic properties described by the van Genuchten formula. 【Result】 ① The cumulative infiltration amount was negatively correlated with the parameter α, positively correlated with the parameter n, and was independent of the residual water content parameter θr. The horizontal advancement of the wetting front was negatively correlated to the parameter α and was independent of the parameter θr. The vertical advancement of the wetting front was negatively correlated to the parameter θr and positively correlated to the parameter n. At the end of infiltration, the volume of the wetted zone was positively correlated to the parameters θrand n. Change in the parameter n had the greatest effect on the size of the wetted zone.② The relative sensitivity of the cumulative infiltration gradually decreased with the increase in α; The positive perturbation of α affected the cumulative infiltration per unit membrane pore area to a weaker extent than the negative perturbation. α occurred in the negative perturbation, the relative sensitivity of the transport distance of the horizontal wetting front increased with the increase of the perturbation amplitude, and α occurred in the positive perturbation, the relative sensitivity of the transport distance of the horizontal wetting front decreased with the increase of the perturbation amplitude.③ When n was negatively perturbed, the relative sensitivities of cumulative infiltration per unit membrane pore area and vertical wetting front transport distance both showed a tendency to increase and then decrease with the increase of perturbation amplitude; when n was positively perturbed, the relative sensitivities of cumulative infiltration per unit membrane pore area showed a tendency to decrease and then increase and then decrease with the increase of perturbation amplitude. 【Conclusion】 Disturbing the parameter n has the most significant effect on water infiltration from the single-point source in membrane hole irrigation, while disturbing the parameter θr had the least effect.

This study investigated the effects of film hole diameter and soil bulk density on the unidirectional intersection infiltration laws of muddy water fertilization film hole irrigation. Indoor soil box infiltration experiments were conducted. The thickness of the sediment layer, cumulative infiltration amount per unit area, vertical wetting front transport distance, moisture distribution in the wetting body, and nitrate and ammonium nitrogen transport laws were observed and analyzed. The results indicated that both the thickness of the sediment layer and the cumulative infiltration per unit area are inversely correlated with film hole diameter and soil bulk density. Conversely, the vertical wetting front transport distance and nitrogen content are positively correlated with film hole diameter, while exhibiting a negative correlation with soil bulk density. Notably, the initial point of intersection for the moist body was located below the soil surface, with the peak vertical soil moisture content at the intersection approximately 1.5 cm beneath the surface. The distribution pattern of soil nitrate nitrogen at the conclusion of infiltration mirrored that of water content, characterized by a sharp decline near the wetting front. In contrast, soil ammonium nitrogen content decreased significantly in the shallow soil layer as soil depth increased, without a corresponding abrupt decrease near the wetting front. These findings may provide a theoretical foundation for future research on the intersection infiltration laws of muddy water fertilization through film hole irrigation. [ABSTRACT FROM AUTHOR]

Despite the high sand content of Yellow River water in arid Northwest China, locals in the region opt to use muddy water to meet the demand for agricultural irrigation. Muddy water irrigation is a complex process and is still poorly understood. In this study, six sets of saturated soil column infiltration tests were designed, considering soil texture (silt loam, sandy loam, and sand) and muddy water sand content (3%, 6%, 9%, and 12%) as the influencing factors, with two sets of validation tests. Change in hydraulic conductivity (Kh), the average change rate of hydraulic conductivity (ΔK), and cumulative infiltration volume (I) were experimentally studied in the context of muddy water infiltration to respectively establish the separate functional models and developed to fit their relationship with time. The study results indicated that the hydraulic conductivity (Kh) decreased with increasing muddy water infiltration time. For silt loam and sandy loam, Kh stabilized at 0.0030 and 0.0109 cm/min, respectively, after 70 min of infiltration. In contrast, Kh in the saturated sandy soil column significantly declined throughout the muddy water infiltration, showing a 90.84% reduction after 90 min compared to the saturated hydraulic conductivity of the sandy soil. As the sand content of the muddy water increased from 3% to 12%, Kh decreased by 83.99%, 90.90%, 91.92%, and 92.21% for 3%, 6%, 9%, and 12% sand content, respectively, in the saturated sandy soil columns at the end of the infiltration period. The I values were 21.20, 9.29, 7.90, and 6.25 cm for 3%, 6%, 9%, and 12% sand content, respectively. The ΔK values were 0.0037, 0.0041, 0.0043, and 0.0044 cm/min2 for the respective sand contents, at an infiltration time of 80 min. The validation test demonstrated that the segmented function model accurately emulated the changes in hydraulic conductivity of sandy soil textures throughout the infiltration period. Results from this study provide a significant basis for understanding the mechanisms to hinder muddy water infiltration and to efficiently utilize muddy water for irrigation. [ABSTRACT FROM AUTHOR]