Simulating the effects of drip and flood irrigation on the leaching, migration, and redistribution of heavy metals in contaminated soil

Abstract

Background

The extensive adoption of drip irrigation globally has adverse effects on the ecological integrity of soil, leading to significant changes in the distribution of heavy metals and other pollutants across various soil layers. However, the mechanisms underlying such changes are still unclear.

Purpose

This study explores the effects of different irrigation methods (drip and flood irrigation) on the heavy metal behaviors in contaminated soils, including leaching, migration, and redistribution within agricultural practices.

Materials and methods

The soil column leaching experiments simulating drip and flood irrigation were performed. The correlation tests and one-way analysis of variance were used for data analysis.

Results

Compared to flood irrigation, drip irrigation resulted in higher leaching; as high as twice of heavy metal redistribution across soil columns. The average changes in heavy metal concentration before and after drip irrigation and flood irrigation were 16.3 % and 3.3 %, respectively. The soil redox potential and contact time were the main factors affecting the migration of heavy metals during the initial stages of irrigation implementation; however, hydrodynamic factors were also influential.

Conclusion

Drip irrigation may pose a serious threat to food safety in the areas with considerable heavy metal pollution due to increased heavy metal leaching and the accumulation of heavy metals near the soil surface, in particular at lower water volume.