Fertilizer application alters cadmium and selenium bioavailability in soil-rice system with high geological background levels

Cheng Zhou; Lianghui Zhu; Tingting Zhao; Randy A Dahlgren; Jianming Xu

doi:10.1016/j.envpol.2024.124033

Fertilizer application alters cadmium and selenium bioavailability in soil-rice system with high geological background levels

Environ Pollut. 2024 Jun 1:350:124033. doi: 10.1016/j.envpol.2024.124033. Epub 2024 Apr 24.

Authors

Cheng Zhou¹, Lianghui Zhu¹, Tingting Zhao¹, Randy A Dahlgren², Jianming Xu³

Affiliations

¹ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China.
² Department of Land, Air and Water Resources, University of California, Davis, 95616, CA, USA.
³ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, 310058, China. Electronic address: jmxu@zju.edu.cn.

PMID: 38670427
DOI: 10.1016/j.envpol.2024.124033

Abstract

The co-occurrence of cadmium (Cd) pollution and selenium (Se) deficiency commonly exists in global soils, especially in China. As a result, there is great interest in developing practical agronomic strategies to simultaneously achieve Cd remediation and Se mobilization in paddy soils, thereby enhancing food quality/safety. To this end, we conducted a field-plot trial on soils having high geological background levels of Cd (0.67 mg kg^-1) and Se (0.50 mg kg^-1). We explored 12 contrasting fertilizers (urea, potassium sulfate (K₂SO₄), calcium-magnesium-phosphate (CMP)), amendments (manure and biochar) and their combinations on Cd/Se bioavailability. Soil pH, total organic carbon (TOC), soil available Cd/Se, Cd/Se fractions and Cd/Se accumulation in different rice components were determined. No significant differences existed in mean grain yield among treatments. Results showed that application of urea and K₂SO₄ decreased soil pH, whereas the CMP fertilizer and biochar treatments increased soil pH. There were no significant changes in TOC concentrations. Three treatments (CMP, manure, biochar) significantly decreased soil available Cd, whereas no treatment affected soil available Se at the maturity stage. Four treatments (CMP, manure, biochar and manure＋urea＋CMP＋K₂SO₄) achieved our dual goal of Cd reduction and Se enrichment in rice grain. Structural equation modeling (SEM) demonstrated that soil available Cd and root Cd were negatively affected by pH and organic matter (OM), whereas soil available Se was positively affected by pH. Moreover, redundancy analysis (RDA) showed strong positive correlations between soil available Cd, exchangeable Cd and reducible Cd with grain Cd concentration, as well as between pH and soil available Se with grain Se concentration. Further, there was a strong negative correlation between residual Cd/Se (non-available fraction) and grain Cd/Se concentrations. Overall, this study identified the primary factors affecting Cd/Se bioavailability, thereby providing new guidance for achieving safe production of Se-enriched rice through fertilizer/amendment management of Cd-enriched soils.

Keywords: Food quality/safety; Heavy metals; Nutrient elements; Soil remediation; Sustainable agriculture.

MeSH terms

Biological Availability
Cadmium* / analysis
Cadmium* / metabolism
China
Fertilizers* / analysis
Oryza* / chemistry
Oryza* / growth & development
Oryza* / metabolism
Selenium* / analysis
Soil Pollutants* / analysis
Soil Pollutants* / metabolism
Soil* / chemistry