Analysis of Water Infiltration Characteristics and Hydraulic Parameters of Sierozem Soil under Humic Acid Addition

Abstract

The farmland in Yinchuan is composed of sierozem soil, which is characterized by high sand content and low organic matter content, resulting in poor water-holding capacity and weak soil structure. Humic acid is a natural organic polymer soil amendment. It is critical to study how humic acid affects soil water infiltration in sierozem soil at the microlevel. A one-dimensional vertical infiltration experiment was conducted to explore how adding different amounts of humic acid (0, 1%, 2%, 3% and 4%) affected the infiltration characteristics and hydraulic parameters of the sierozem soil. The results revealed that the wetting front and cumulative infiltration decreased with the increase in humic acid addition. When the infiltration time was 90 min, the wetting front of the 1%, 2%, 3% and 4% treatments was 6.50%, 10.00%, 15.00% and 21.00% lower than CK (0 for CK), and the cumulative infiltration volume was 4.50%, 11.14%, 18.42% and 23.60% lower than CK, respectively. Among the three infiltration models created by Philip, Horton and Kostiakov, the Kostiakov model (R2 > 0.95) could more accurately describe the soil water infiltration process in the study area. After infiltration, the moisture content of each soil layer increased with the increase in humic acid, which improved the water-holding capacity of the sierozem soil. Using Hydrus-1D to calculate soil hydraulic parameters, we found that the humic acid addition affected the hydraulic parameters. With the increase in the amount of humic acid addition, the retention water content θr and saturated water θs were positively correlated with the humic acid addition amount and negatively correlated with the saturated water conductivity Ks and the reciprocal of air-entry α. The results showed that humic acid could increase the water-holding capacity of soil and improve the rapid water loss and poor water-holding capacity of sierozem soil.

Effect of Humic Amendment on Selected Hydrophysical Properties of Sandy and Clayey Soils

“…In various studies, these substances have been used to affect the soil hydrophysical characteristics [26,27]. For instance, Xu et al [28] and Ma et al [29] discovered that the application of humic acids increased the soil's water retention capacity by enhancing macroaggregation. Likewise, Wu et al [30] conducted a soil column experiment and reported that the incorporation of humic acids promoted soil infiltration.…”

“…Regarding leonardite, various studies confirm its ability to improve the content and quality of organic matter and the soil's nutrient content and increase plant production. Many studies [23][24][25][26][28][29][30] examined the effect of humic acids on soil hydrophysical properties, but only a few dealt with leonardite as a source of humic acids. The purpose of this study was to assess how a commercial humic acid product affects the hydrophysical properties of sandy and clayey soils.…”

Effects of gravel on the water infiltration process and hydraulic parameters of stony soil in the eastern foothills of Helan Mountain, China

“…Tadesse et al 34 used Hydrus-1D to simulate soil water content and soil temperature combining data on precipitation, evaporation, and average temperature. Ma et al 35 used infiltration data and Hydrus-1D model to simulate and analyze the impact of humic acid addition on hydraulic parameters, the results of which showed that simulation results met the accuracy requirements. However, there were few studies using infiltration data and Hydrus-1D model to invert the hydraulic parameters of stony soil in the eastern foothills of Helan Mountain.…”