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| DOI：10.13522/j.cnki.ggps.2019037 |
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| Effect of Natural Zeolite on Soil Water Movement Characteristics and Water Stability Aggregates |
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WU Junhu, LIU Xia, SHAO Fanfan, LI Yuchen, WANG Zexiang
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State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi’an University of Technology, Xi’an 710048, China
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| Abstract: |
| In the loess area of China, the problems of drought, lack of rainfall and shortage of water and soil resources are increasingly prominent. The soil quality is seriously degraded, which restricts the development of local agriculture. Zeolite plays an important role in soil structure and nutrient improvement. The aggregate content is closely related to the stability of soil structure. Soil water movement affects infiltration and runoff process. 【Objective】This paper is to study the effects of zeolite on soil water movement and aggregate distribution, and to provid theoretical basis for improving the structure and water storage capacity of loess area, increasing crop yield and increasing growth, and sustainable development of agriculture.【Method】 By adding different proportion of zeolite to soil, indoor soil column test and water stability aggregate analysis test were carried out. The effects of adding 0%, 5%, 10%, 15%, and 20% zeolite on soil water infiltration, soil water stability aggregate volume, average mass diameter and fractal dimension were studied. 【Result】 Zeolite could reduce the amount and rate of cumulative soil infiltration, and hinder the advancement of the wetting front. Compared with the control group, the cumulative infiltration amount and rate of the zeolite test group were continuously reduced. When 20% zeolite was added, the infiltration amount, rate, and wetting front decreased the most. Kostiakov and Philip infiltration models were used to fit the experimental data. After fitted, R2 was greater than 0.99, and the fitting effect was better. The fitting parameters A and S were smaller than those in the control group.The absorption rate and stable infiltration rate decreased in different degrees, further verify that zeolite could slow down infiltration. The effect of zeolite on water-stable aggregates and fractal dimensions had a greater relationship with its content. When the zeolite content was increased from 0 to 10%, the content of water-stable aggregates in ≥0.25 mm increased from 10.8% to 18.3% and the fractal dimension decreased from 2.69 to 2.58. The aggregate volume of water stability increased, and the soil erosion resistance and permeability increased. When the zeolite content was increased to 20%, the content of ≥0.25 mm aggregates decreased to 6%, and the fractal dimension increased to 2.72, at which time, the soil structure became poor. The changes of fractal dimension and soil aggregate indicated that zeolite can improve soil structure. When the amount of zeolite was 5%, 10% and 15%, the MWD of the soil increased, and the maximum was at 15%. The amount of zeolite added continued to increase to 20%, and the MWD of the soil decreased to 0.151, which was 10.65% lower than that of the control group.【Conclusion】It shows that zeolite can slow down the process of soil moisture infiltration. Within a certain range, zeolite can increase the content of water-stable aggregates in the soil. When the content of zeolite increased to 20%, the content of water stable aggregate decreases greatly, which shows that the excessive application of zeolite will destroy the soil structure. This study can provide a theoretical basis for the improvement of black loam soil by zeolite. |
| Key words: zeolite; soil aggregate; soil amendment; infiltration |
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