Flue gas desulfurization (FGD) steel slag ameliorates salinity, sodicity, and adverse physical properties of saline-sodic soil of middle Yellow River, China

Yuqian Ying; Shenggao Lu; Hanxiang Shi; Yuezhan Shi; Yuenu Shi; Wenjun Rao; Changsheng Liu; Yurong Liu

doi:10.1007/s11356-021-13338-2

Flue gas desulfurization (FGD) steel slag ameliorates salinity, sodicity, and adverse physical properties of saline-sodic soil of middle Yellow River, China

Environ Sci Pollut Res Int. 2021 Jul;28(27):36765-36774. doi: 10.1007/s11356-021-13338-2. Epub 2021 Mar 12.

Authors

Yuqian Ying^{1

2

3}, Shenggao Lu^{4

5

6}, Hanxiang Shi⁷, Yuezhan Shi⁷, Yuenu Shi⁷, Wenjun Rao⁷, Changsheng Liu⁷, Yurong Liu⁷

Affiliations

¹ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China.
² Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education, Zhejiang University, Hangzhou, 310058, China.
³ College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
⁴ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China. lusg@zju.edu.cn.
⁵ Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education, Zhejiang University, Hangzhou, 310058, China. lusg@zju.edu.cn.
⁶ College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. lusg@zju.edu.cn.
⁷ Ningbo Taiji Environmental Protection Equipment Co., Ltd., Ningbo, 315301, China.

PMID: 33712953
DOI: 10.1007/s11356-021-13338-2

Abstract

Saline-sodic soil is considered the most important low-yield soil in arid and semi-arid regions. Flue gas desulfurization (FGD) steel slag is a kind of by-product from wet FGD process, in which steel slag powder replaces lime as sorbent of SO₂ emitted from coal-fired power plants. It could potentially be used to ameliorate saline-sodic soil. In this study, a large-scale field experiment of applying FGD steel slag as a new amendment of saline-sodic soils was conducted in the middle Yellow River, Inner Mongolia, China. The FGD steel slag was applied at a rate of 180 t/ha in 2015, 2016, and 2018, respectively. After FGD steel slag application for 1, 3, and 4 years, the soil samples were collected. The saline-sodic field without FGD steel slag amendment was used as the control treatment (CK). Compared with control, the application of FGD steel slag significantly (p < 0.05) decreased soil pH, electric conductivity (EC), salt content, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of surface soil in saline-sodic soil. However, FGD steel slag increased the EC and salt content at the lower depth of soil profile because of the salt accumulation leached from surface soil. The FGD steel slag significantly increased the concentration of Ca²⁺ and reduced the concentrations of Na⁺, Cl^-, CO₃^2-, and HCO₃^- ions. FGD steel slag was beneficial for improving adverse physical properties of saline-sodic soil. The application of FGD steel slag significantly reduced the plastic index, tensile strength, and the formation of cracking in saline-sodic soil. The FGD steel slag reduced surface area density of crack (Dc) and average crack width (AW) by 49.1% and 58.7%, compared with the control. The reduction of soil cracking was contributed to the release of Ca²⁺ from FGD steel slag to exchange the Na⁺ on the soil cation exchange sites, which decrease the clay dispersion in soil. The findings of this study confirmed that FGD steel slag could effectively and rapidly remediate saline-sodic soils through decreasing soil sodicity and improving poor physical properties.

Keywords: Exchangeable sodium percentage; FGD steel slag; Responsible editor: Kitae Baek; Saline-sodic soil; Soil cracking; Soil pH.

MeSH terms

China
Rivers
Salinity*
Soil*
Steel

Substances

Soil
Steel

Grants and funding

2018B10091/Science and Technology Innovation 2025 Major Project of Ningbo City, China