ABSTRACT
The aim of this study was to ascertain the utility of using the freshwater snail Ampullaria tischbeini as a biological control agent for the remediation of soil impacted with high levels of Na+. A. tischbeini has an important role in improving the physical and chemical properties of soils. Calcium (Ca2+) ions required to ameliorate sodic soil originate from the snail shells. As the snail shells decompose by natural chemical processes, they produce Ca2+ ions. The sodium adsorption ratio (SAR) in the plots with snails was dramatically decreased as compared to the control plot without snails. After two years, the mean SAR value at 0–10 cm soil depth was decreased by 23.5 in the plots with snails. The snail movements in sodic soils improved soil physical properties with an increase in infiltration rate and a decrease in bulk density. In 2012, the mean bulk density was 137 and 64 kg m–3 lower at 0–10 and 10–20 cm soil depths in the plots with snails, respectively, as compared to the control plot without snails. The experimental results demonstrate that A. tischbeini can be used as a biocontrol agent with potential utility for the remediation of sodic soils.
Acknowledgments
The authors would like to thank our colleagues for the joined field experiment and data analysis. The field experiment was carried out at farms in Yomju County, North Phyongan Province, the DPR Korea. We also appreciate the comments of two anonymous reviewers and the editor for this manuscript and acknowledge their contributions to improve the manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.