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Sustainable effects of gypsum from desulphurization of flue gas on the reclamation of sodic soil after 17 years
Author(s) -
Zhao Yonggan,
Wang Shujuan,
Li Yan,
Zhuo Yuqun,
Liu Jia
Publication year - 2019
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.12807
Subject(s) - gypsum , sodic soil , loam , land reclamation , chemistry , soil water , soil ph , flue gas desulfurization , environmental science , environmental chemistry , soil science , geology , ecology , paleontology , organic chemistry , biology
Reclamation of saline–sodic soils with gypsum from the desulphurization of flue gas (FGD) is a recently developed technique. However, limited information is available on the long‐term effects of FGD gypsum in agricultural fields. This study evaluated the effects of FGD gypsum on soil physical and chemical properties and heavy metal concentrations after 17 years. Established in 2001, the study site on the Tumochuan Plain of Inner Mongolia, China, has a sandy loam soil. The experimental field was divided into three classes characterized by small, medium and large exchangeable sodium percentage (ESP) values before the experiment. Based on the initial soil ESP values (6.1–20, 20–30 and 30–78.4%, respectively), FGD gypsum was applied once at rates of 20.9, 30.6 and 59.3 t ha −1 to the small‐, medium‐ and large‐ESP classes, respectively. Compared with the control plots, the treated plots showed decreases in soil pH of 9.8 and 7.5% and decreases in ESP of 52.7 and 46.6% at the 20–40‐cm and 40–60‐cm depths, respectively. The treated plots showed remarkable decreases in electrical conductivity at the 20–60‐cm depth in the small‐ESP class, but moderate increases at the 0–20‐cm depth in the medium‐ and large‐ESP classes. The dissolved salt composition changed, with substantially larger Ca 2+ and SO 4 2− but smaller CO 3 2− + HCO 3 − concentrations in the treated plots than in the control plots. The treated plots showed increases in the macroaggregate fractions (>250 μm) and decreases in the silt–clay fractions (<53 μm). There were no significant differences in the heavy metal (Cd, Hg, As, Pb, Cr, Cu, Zn and Ni) concentrations among the plots; thus, the use of FGD gypsum in agricultural fields is safe. The beneficial effects of FGD gypsum on the reclamation of sodic soils remained and were concentrated deeper in the soil after 17 years. Highlights Limited information is available on the lasting effects of FGD gypsum in agricultural fields. The long‐term effects of FGD gypsum on soil physicochemical properties are reported for the first time. The beneficial effects of FGD gypsum on soil reclamation extended to the 20–60‐cm soil layers. The use of FGD gypsum in agricultural fields was safe, and the effects lasted many years.