Liang et al. 2024 - Rice cadmium reduction with Fe-modified biochar and green-manure DOM

Liang and colleagues tested whether dissolved organic matter from co-decomposed Chinese milk vetch and rice straw strengthens Fe-modified biochar immobilization of cadmium in a paddy-rice pot experiment. The food-matrix endpoint is brown-rice Cd, not rice milk: the combined Fe-modified biochar plus milk-vetch/rice-straw treatment lowered brown-rice Cd by 86.2% versus untreated soil, 82.5% versus the organic-residue mixture alone, and 34.7% versus Fe-modified biochar alone. The source is useful for agronomic mitigation and rice-grain Cd routing, but it is not a market-occurrence survey and should not be pooled as a consumer-market benchmark distribution.

Key numbers

• Pot experiment: October 2021 to July 2022, Changsha City, Hunan Province, China.
• Treatments: untreated paddy soil (CK-S), Chinese milk vetch (MV-S), rice straw (RS-S), milk vetch plus rice straw (MR-S), Fe-modified biochar (FB-S), and Fe-modified biochar plus milk vetch/rice straw (MRFB-S).
• Replication: each of the six treatments was replicated four times, for 24 experimental pots.
• MRFB-S reduced available soil Cd by 81.4% versus CK-S, 76.3% versus MR-S, and 23.1% versus FB-S.
• MRFB-S increased DCB-extractable Fe in rice root iron plaque by 11.8% versus FB-S, and increased DCB-Fe and DCB-Cd by 37.2% and 35.9% versus MR-S.
• MRFB-S lowered brown-rice Cd by 86.2% versus CK-S, 82.5% versus MR-S, and 34.7% versus FB-S.
• The authors report that brown-rice Cd under MRFB-S did not exceed the cited Cd safety threshold of 0.2 mg/kg.
• MRFB-S lowered shoot and root Cd by 77.7% and 58.8% versus MR-S, respectively.
• Adsorption experiment: Fe-modified biochar after addition of DOM-MR had a maximum Cd(II) adsorption capacity of 634 mg/g, 1.30 times the capacity without DOM-MR.

Methods (brief)

The pot trial used Cd-polluted paddy soil with six amendment treatments and four replicates per treatment. Rice was transplanted after in situ incorporation of milk vetch, rice straw, and/or Fe-modified biochar. The paper paired plant-tissue Cd measurements with soil Cd fractions, available Cd, root iron-plaque measurements, and adsorption studies. DOM was characterized by EEM-PARAFAC and FT-ICR MS; biochar/adsorption mechanisms were assessed with FT-IR, XRD, XPS, BET surface analysis, and adsorption kinetic and thermodynamic modeling. Cd in brown rice is reported as a total Cd concentration; the extractable text gives percent reductions and the 0.2 mg/kg threshold comparison, while the absolute brown-rice bar-chart values are not printed in the text layer.

Implications

• Rice and rice products: supports agronomic mitigation context for Cd uptake into brown rice under Cd-polluted paddy-soil conditions.
• Product routing: route as rice-grain/brown-rice evidence, not rice-milk evidence despite the wishlist query term.
• Standards workbench: not a market-occurrence distribution; use as mitigation evidence rather than a benchmark-pool row.
• Testing and methods: Cd species are not speciated; this is total Cd in rice tissues and soil fractions.

Wiki pages this source may touch

• rice
• rice-bulk-grain
• cadmium

Verification notes

• The auto-fetched filename/wishlist cell was rice milk Cd, but the PDF measures paddy soil, rice tissues, and brown rice. No rice milk or plant beverage matrix is present.
• The paper’s extractable text reports the brown-rice Cd percentage reductions and threshold comparison; exact absolute brown-rice concentrations are plotted in Figure 3 but not printed as text.
• The source is a remediation pot experiment with four replicates per treatment, not a retail or field-market occurrence survey.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.