Abstract
Applying soil amendments plays a critical role in relieving water stress in arid and semiarid areas. The natural clay mineral attapulgite (ATP) can be utilized to adjust the balance of water and soil environment. In this study, we investigated four different particle size distribution typical soils in the Loess Plateau: (1) lou soil (LS), (2) dark loessial soil (DS), (3) cultivated loess soil (CS), (4) sandy soil (SS). Five ATP application rates (0, 1%, 2%, 3%, and 4%) were selected to test the effect of ATP on the soil water retention curve, soil saturated hydraulic conductivity, and soil structure. The results showed that applied ATP significantly increased the soil clay content, and the relative change of SS with 3% ATP applied increased by 53.7%. The field water holding capacity of LS, DS, CS, and SS with 3% ATP applied increased by 8.9%, 9.6%, 18.2%, and 45.0%, respectively. Although applied ATP reduced the saturated hydraulic conductivity, the values of CS and SS were opposite when the amount of ATP applied was >3%. The relative change in the amount of 0.25–1 mm soil water-stable aggregates of SS was 155.9% when 3% ATP was applied. Applied ATP can enhance soil water retention and soil stability, which may improve limited water use efficiency and relieve soil desiccation in arid and semiarid areas or similar hydrogeological areas.
Highlights
Arid and semiarid areas occupy more than 40% of the terrestrial ecosystem, and support over 35% of the global population [1]
Adding ATP enhanced the clay content compared with CK treatments
Statistical analysis revealed that ATP has no significant effect on the capillary porosity (CP), but has significant effects on other physical parameters
Summary
Arid and semiarid areas occupy more than 40% of the terrestrial ecosystem, and support over 35% of the global population [1]. The fibrous morphology and pore structure of ATP make it significant in improving soil strength and caking, and its large specific surface area and cation exchange capacity enable it to play a role in water retention and improving soil aeration [23,37,38]. A large number of studies have shown that ATP exhibits excellent heavy metal absorption properties in soil remediation, greatly reducing soil contamination [36,37,40]. We propose the following hypotheses: (1) applied ATP improves the water holding capacity significantly, (2) the soil structure will be improved within a specific range of addition by adding ATP, and (3) ATP has a more beneficial effect on sandy soil than other soils
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