Targeting severe saline‐sodic soils in western Songnen Plain of China: A new perspective on critical flocculation concentration for clay dispersion
- 1Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun China
- 2Faculty of Agronomy, Jilin Agricultural University Changchun China
Abstract
The critical flocculation concentration (CFC) of clay dispersion in saline‐sodic soils is pivotal for restoring aggregate stability, alleviating salinity/sodicity, and sustaining agroecosystem productivity. To delineate the CFC governing clay dispersion in severe saline‐sodic soils, this study investigated clay flocculation‐dispersion dynamics in Songnen Plain soils under systematic CaCl2 leaching, providing mechanistic insights and quantitative benchmarks for targeted mitigation. A soil column leaching experiment was conducted with CaCl2 solutions across an 11‐point gradient (0–100 mmol L−1, 10 mmol L−1 increments). Post‐leaching, key physicochemical properties (pH, EC, Na+, HCO3−, CO32−, sodium adsorption ratio [SAR], and exchangeable sodium percentage [ESP]) and clay dispersion indices (turbidity, zeta potential, water‐dispersible clay [WDC], total clay, clay dispersion rate [CDR], and clay flocculation index [CFI]) were quantified. Nonlinear regression (Sigmoid model) was used to determine the CFC and establish predictive relationships between CaCl2 concentration, soil properties, and dispersion behavior. Results showed 30–40 mmol L−1 CaCl2 effectively inhibited clay dispersion. This dosage improved soil properties: pH, SAR, cations ratio of soil structural stability, and ESP decreased to 8.01, 2.32 (mmolc L−1)1/2, 2.97 (mmolc L−1)1/2, and 4.98, respectively. Clay dispersion indices also improved: WDC, mechanical dispersion turbidity, spontaneous dispersion turbidity, mechanical dispersion zeta potential, and CDR declined to 2.93%, 59.93 Nephelometric Turbidity Units (NTU), 1.96 NTU, −22.09 mV, and 0.15, while CFI increased to 0.85. The Sigmoid model well described nonlinear relationships, identifying the CFC as 30–40 mmolc L−1 Ca2+. Univariate regression models were developed to optimize Ca2+ amendment dosages and quantitatively forecast post‐treatment clay dispersion behavior.
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BibTeX
@article{luo2026targeting,
title = {{Targeting severe saline‐sodic soils in western Songnen Plain of China: A new perspective on critical flocculation concentration for clay dispersion}},
author = {Xuejiao Luo and Xin Zhang and Runze Wang and Lu Zhang and Zhaoyang Nie and Jie Zhou and Tieyi Zhang and Yue Miao and Le Ma and Zhichun Wang and Fan Yang},
journal = {Vadose Zone Journal},
year = {2026},
month = sep,
doi = {10.1002/vzj2.70132},
url = {https://doi.org/10.1002/vzj2.70132},
note = {CC BY},
}
RIS
TY - JOUR
TI - Targeting severe saline‐sodic soils in western Songnen Plain of China: A new perspective on critical flocculation concentration for clay dispersion
AU - Xuejiao Luo
AU - Xin Zhang
AU - Runze Wang
AU - Lu Zhang
AU - Zhaoyang Nie
AU - Jie Zhou
AU - Tieyi Zhang
AU - Yue Miao
AU - Le Ma
AU - Zhichun Wang
AU - Fan Yang
PY - 2026
DA - 2026/09/01
JO - Vadose Zone Journal
DO - 10.1002/vzj2.70132
UR - https://doi.org/10.1002/vzj2.70132
AB - The critical flocculation concentration (CFC) of clay dispersion in saline‐sodic soils is pivotal for restoring aggregate stability, alleviating salinity/sodicity, and sustaining agroecosystem productivity. To delineate the CFC governing clay dispersion in severe saline‐sodic soils, this study investigated clay flocculation‐dispersion dynamics in Songnen Plain soils under systematic CaCl2 leaching, providing mechanistic insights and quantitative benchmarks for targeted mitigation. A soil column leaching experiment was conducted with CaCl2 solutions across an 11‐point gradient (0–100 mmol L−1, 10 mmol L−1 increments). Post‐leaching, key physicochemical properties (pH, EC, Na+, HCO3−, CO32−, sodium adsorption ratio [SAR], and exchangeable sodium percentage [ESP]) and clay dispersion indices (turbidity, zeta potential, water‐dispersible clay [WDC], total clay, clay dispersion rate [CDR], and clay flocculation index [CFI]) were quantified. Nonlinear regression (Sigmoid model) was used to determine the CFC and establish predictive relationships between CaCl2 concentration, soil properties, and dispersion behavior. Results showed 30–40 mmol L−1 CaCl2 effectively inhibited clay dispersion. This dosage improved soil properties: pH, SAR, cations ratio of soil structural stability, and ESP decreased to 8.01, 2.32 (mmolc L−1)1/2, 2.97 (mmolc L−1)1/2, and 4.98, respectively. Clay dispersion indices also improved: WDC, mechanical dispersion turbidity, spontaneous dispersion turbidity, mechanical dispersion zeta potential, and CDR declined to 2.93%, 59.93 Nephelometric Turbidity Units (NTU), 1.96 NTU, −22.09 mV, and 0.15, while CFI increased to 0.85. The Sigmoid model well described nonlinear relationships, identifying the CFC as 30–40 mmolc L−1 Ca2+. Univariate regression models were developed to optimize Ca2+ amendment dosages and quantitatively forecast post‐treatment clay dispersion behavior.
SN - 1539-1663
ER -