Li Qi, Li Linfeng, Yin Bohao, Lin Xiaoyang, Xiao Anwen, Xue Weijie, Liu Hengjie, Li Yichun
Institute of Agricultural Resources and Environment, Guangdong Academy of Agricultural Sciences, Guangdong Key Laboratory of Nutrient Cycling and Farmland Conservation, Key Laboratory of Plant Nutrition and Fertilizer in South Region, Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China.
School of Earth System Science, Tianjin University, Tianjin 300072, China.
Ecotoxicol Environ Saf. 2025 Jan 1;289:117457. doi: 10.1016/j.ecoenv.2024.117457. Epub 2024 Dec 6.
Soil amendments are crucial in regulating cadmium (Cd) distribution as aggregates of varying sizes have different capacities to retain soil Cd. Directly observing the Cd distribution within aggregates and understanding their interactions with minerals and carbon at the submicron scale remain significant challenges. Pot experiments were conducted to assess the impacts of mineral, organic, and microbial amendments on the Cd distribution in soil aggregates using synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectroscopy and nano-scale secondary ion mass spectrometry (NanoSIMS). Our results revealed that different soil amendments exerted varying effects on Cd accumulation in soil aggregates. The mineral and microbial amendments facilitated the Cd transfer from the macroaggregates to the silt+clay fraction, while the organic amendment increased the Cd loading in the macroaggregates. Additionally, the mineral and microbial amendments reduced the binding of Fe oxides with microbial-derived peptides in the macroaggregates and enhanced the interaction of Fe oxides with plant-derived lignin in the silt+clay fractions. Furthermore, NanoSIMS analysis provided direct evidence that the mineral and microbial amendments decreased the association between Cd with carbon and minerals in the macroaggregates, while they enhanced the binding of Cd and Fe oxides in the silt+clay fractions. Collectively, our findings revealed that the mineral and microbial amendments promoted Cd transfer, enhancing the stability of Cd in the finer soil fractions and offering essential insights for developing agricultural management strategies to alleviate Cd contamination in paddy soils.
