موسسه تحقیقات خاک و آب پژوهش های خاک 2228-7124 39 4 2026 03 16 Investigating the Role of Soil Physical Properties on Water Infiltration Indices (Case Study: Zanjan Province) بررسی نقش ویژگی‏های فیزیکی خاک بر شاخص‌های نفوذ آب در خاک (مطالعه موردی: استان زنجان) 421 436 135012 10.22092/ijsr.2026.370662.796 FA مرتضی یاوری گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه زنجان، زنجان، ایران. علی رضا واعظی گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه زنجان، زنجان، ایران. محمد صادق عسکری گروه علوم و مهندسی خاک، دانشکده کشاورزی، دانشگاه زنجان، زنجان، ایران. Journal Article 2025 10 27 Background and Objectives: Infiltration is one of the most important hydraulic properties of soil, representing the entry of water into the soil, which usually occurs in a vertical direction. This soil property plays a crucial role in the natural water cycle and has significant implications for soil management. In semi-arid regions, this hydraulic property is particularly important not only for meeting the water requirements of rangeland and rainfed crops but also for reducing runoff and soil erosion. Several factors influence soil infiltration, and they can be generally categorized into three groups: (1) surface characteristics, (2) soil properties, and (3) climatic and environmental conditions. This study focused on soil physical properties, with the aim of quantifying the influence of a wide range of these properties on water infiltration and identifying the most important factors in selected soils in a semi-arid region. Materials and Methods: To investigate the role of soil physical properties on soil water infiltration indices, 68 sites in a semi-arid climate of Zanjan province were selected. To capture sufficient variability for examining the effects of physical factors on soil water infiltration, the sites were chosen based on criteria such as land use type, vegetation cover, and soil texture, ensuring that the experiments were conducted on the predominant soils of the region. At each sampling site, 14 consecutive readings of infiltration depth were recorded at specific time intervals until the infiltration rate reached a steady state flow, for the calculation of various soil water infiltration indices. To evaluate soil water infiltration in detail, six key indices—cumulative infiltration (CI), initial infiltration (II), initial infiltration rate (IIR), final infiltration rate (FIR), mean infiltration rate (MIR), and effective infiltration depth (EID)—were determined. In addition to field infiltration measurements, disturbed and undisturbed soil samples were collected from the 0–60 cm soil depth as the active hydrological layer, and transferred to the laboratory. The following soil physical properties were determined: particle size distribution (PSD), gravel content, bulk density (BD), initial soil moisture, mean weight diameter of dry aggregates (MWDdry), and mean weight diameter and geometric mean diameter of water-stable aggregates (MWDwet and GMDwet). Results: Pearson correlation analysis revealed that the MWDwet and GMDwet of water-stable aggregates were significantly correlated with all infiltration indices (p< 0.05). Bulk density also exhibited significant correlations with CI, II, FIR, and MIR (p < 0.05). Moreover, multiple regression results indicated that physical properties including BD, initial soil moisture, gravel content, PSD, and GMDwet are the main factors controlling water infiltration in these soils. According to one-way ANOVA, the soils were classified into four groups based on BD, MWDwet, and GMDwet. Significant differences were found among GMDwet groups in CI, II, and FIR (p < 0.05). Differences among the groups of MWDwet in CI and II were significant. Additionally, significant differences were found among the BD groups in CI. This study indicated that, along with soil structure, the particle size distribution of soils can affect soil structure and porosity and, in turn, impact water infiltration in semi-arid soils. Conclusion: The results showed that MWDwet and GMDwet of water-stable aggregates, along with BD, have the highest correlations with soil water infiltration indices. These three soil physical properties can be considered the most important determining factors in explaining soil water infiltration. It was also found that PSD indirectly influences MWDwet, GMDwet, and BD and, consequently, affects soil infiltration behavior. These findings emphasize the importance of PSD and soil structure in the process of soil water infiltration in semi-arid regions. هدف این پژوهش بررسی نقش برخی ویژگی‌های فیزیکی خاک در نفوذ آب به خاک در برخی خاک‌های منطقه نیمه‌خشک زنجان بود. بدین منظور، ۶۸ نقطه با تنوع بافت، کاربری و پوشش گیاهی، انتخاب و آزمایش‌های نفوذ با استفاده از استوانه مضاعف انجام شد. در نمونه‌های خاک (صفر تا 60 سانتیمتر) ۱2 ویژگی فیزیکی اندازه‌گیری شد. شش شاخص نفوذ شامل: نفوذ تجمعی (CI)، نفوذ اولیه (II)، شدت‌ نفوذ اولیه (IIR)، شدت نفوذ نهایی (FIR)، شدت نفوذ متوسط (MIR) و عمق مؤثر نفوذ (EDI) تعیین شدند. نتایج همبستگی پیرسون نشان داد که میانگین وزنی (MWDwet) و هندسی (GMDwet) قطر خاکدانه‌ها در حالت تر با همه شاخص‏های نفوذ رابطه معنی‏دار داشت (p< 0.05). چگالی ظاهری (BD) با CI، II، FIR و MIR همبستگی معنی‏دار داشت (p< 0.05). نتایج رگرسیونی نشان داد ویژگی‌های فیزیکی خاک شامل: چگالی ظاهری، رطوبت اولیه، سنگریزه، توزیع اندازه ذرات و میانگین هندسی قطر خاکدانه‏ها نقش محوری در تعیین نفوذ آب در خاک داشتند. برای انجام تحلیل واریانس یک‌طرفه، خاکها در چهار گروه بر مبنای BD، MWDwet و GMDwet تقسیم شدند. تفاوت معنیداری بین سطوح مختلف GMDwet از نظر CI، II و FIR وجود داشت (p< 0.05). همچنین تفاوت بین سطوح مختلف MWDwet از نظر CI و II معنی‌دار بود و در مورد سطوح مختلف BD، تفاوتها تنها از نظر CI معنی‌دار بود. این پژوهش نشان داد که علاوه بر ساختمان خاک، توزیع اندازه ذرات اولیه نیز با اثرگذاری بر شاخص‌هایی مانند چگالی ظاهری، تخلخل و پایداری خاکدانه‌ها، نقش مؤثری در نفوذ آب در خاک‌های منطقه نیمه‌خشک دارد.

https://srjournal.areeo.ac.ir/article_135012_f5fed7c0ca0015b391d7653e2412521c.pdf