Response of Water Stability of Lateritic Aggregates with Different Land Use Types Under Different Antecedent Moisture Content
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1.Huazhong agricultural university;2.HuaZhong Agricultural;3.Huazhong Agricultural University

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National Natural Scicnce Foundation of China (Nos. 42077067, 42277329)

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    Abstract:

    【Objective】 Antecedent moisture content is a critical factor affecting soil aggregate stability. However, its influence on the aggregate stability of lateritic soils developed from basalt has not been systematically investigated. To unravel the intricate interplay between soil properties, antecedent moisture content, and the water stability of lateritic soils developed from basalt, a meticulous investigation was undertaken. This study delved into the diverse land use types, aiming to shed light on the intricate relationship between these factors and aggregate water stability. 【Method】 In the latosol region of Hainan, a comprehensive study was conducted to examine the influence of three prevalent land use types, forest, cropland, and wasteland, on the soil properties and aggregate size distribution. Through a preliminary investigation, the tested soils were meticulously analyzed. The LB method, specifically the Fast Wetting variant, was employed to determine the aggregate size distribution within the 3-5 mm range across the various land use types. This assessment was performed under five distinct antecedent moisture contents of 3%, 5%, 10%, 15%, and 20%. Subsequently, water stability indices, including Water Stability Index ( WSA), Mean Weight Diameter (MWD ), and Geometric Mean Diameter (GMD ), were meticulously calculated to provide valuable insights into aggregate water stability. 【Result】Distinctive variations in soil properties, encompassing pH, organic carbon, cation exchange capacity, and some exchangeable base cations, were prominently observed across different land use types. The distribution of water-stable aggregates in the lateritic soil exhibited either an unimodal or bimodal pattern, with peaks predominantly observed at 2-1 mm and 0.5-0.25 mm size fractions. Notably, forest soils displayed the highest aggregate stability among surface soils, while cultivated soils exhibited relatively weaker aggregate stability. Furthermore, subsurface soils demonstrated significantly lower aggregate stability (P<0.05) compared to surface soils. When considering air-dry conditions, characterized by moisture content during air-drying, the water stability of surface soil aggregates consistently exhibited high values (WSA > 90%, MWD > 1.5, GMD > 1.2). As the antecedent moisture content increased, the proportion of macro aggregates (> 2 mm) following aggregate fragmentation displayed varying degrees of change, ultimately resulting in an overall increase in the content of macro aggregates (> 2 mm). It is noteworthy that the influence of land use type on aggregate water stability outweighed that of antecedent moisture content (F >56, P<0.01). Soil organic carbon (SOC) emerged as the primary factor explaining the variation in aggregate stability (R2=80.6%, P<0.01), displaying a positive correlation. Non-capillary porosity followed suit, exhibiting a significant positive correlation (R2 = 66.0%, P<0.01), while capillary porosity demonstrated a noteworthy negative correlation. Among the soil sesquioxides, aluminum oxides (Ald, Alo) exerted a considerably larger impact on aggregate stability compared to other sesquioxides. In contrast, the influence of antecedent moisture content on aggregate stability was relatively modest, displaying a significant negative correlation (R2 = 24.0%, P< 0.01). 【Conclusion】The water stability of lateritic soil aggregates, which developed from basalt, exhibited pronounced sensitivity to land use, with forested areas surpassing wastelands and croplands surpassing cultivated land in terms of water stability. Additionally, the water stability of these lateritic soil aggregates showed an initial increase followed by a subsequent decrease as the antecedent moisture content increased. Notably, when compared to red soil, lateritic soil aggregates displayed a lower sensitivity to dissipative effects. The primary determinant influencing the stability of lateritic soil aggregates is the concentration of SOC. Variations in the stability of these aggregates across different land uses can be attributed to fluctuations in SOC levels.

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WANG Jie, REN Shaocong, WEI Yujie, HUANG Yijing, YANG Bangge, CAI Chongfa. Response of Water Stability of Lateritic Aggregates with Different Land Use Types Under Different Antecedent Moisture Content[J]. Acta Pedologica Sinica,2024,61(4).

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History
  • Received:January 06,2023
  • Revised:October 08,2023
  • Adopted:November 23,2023
  • Online: November 28,2023
  • Published: