ORIGINAL RESEARCH
Leaching of Heavy Metals from Rice Fields
with Different Irrigation Management
Junzeng Xu1,2, Qi Wei2, Yanmei Yu2, Shizhang Peng1, Shihong Yang1,2
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1State Key Laboratory of Hydrology–Water Resources and Hydraulic Engineering,
2College of Water Conservancy and Hydropower Engineering,
Hohai University, Nanjing 210098, China
Pol. J. Environ. Stud. 2014;23(6):2279-2286
KEYWORDS
ABSTRACT
To reveal the impact of irrigation management on the release and leaching of soil metals (Cu, Zn, Pb,
Cr, and Cd), deep percolation rate and metals contents in soil solutions were observed in rice fields with nonflooding
controlled irrigation (NFI) and flooding irrigation (FI) treatments. The contents of Cu and Cr in the
deep solutions were safe according to the environmental quality standard for groundwater, but contents of
other metals might lead to groundwater contamination, especially for Cd. The release of metals in surface soil
was increased for NFI because the wetting-drying cycles in NFI fields resulted in less reluctant and high
decomposition and mineralization of soil organic matter in surface soil, and consequently enhanced the release
of soil metals into solutions. Seasonal metals leaching losses in NFI fields were 44.9-53.8% lower than in FI,
due to the large reduction in both deep seepage rates and metals concentrations in deep soil solutions. Higher
release of metals in NFI surface soils might lead to higher bioavailability of micronutrients (Cu and Zn) to
crops, but higher risks in toxic metals (Pb, Cr, and Cd) uptakes.