Field application of biochar-based amendments for safe crop production in karst paddy with a high geological background: Unraveling Cd-Se dynamics
- 1School of Environment, Tsinghua University
- 2Guangxi Zhuang Autonomous Region Ecological and Environmental Monitoring Centre
- 3State Key Laboratory of Regional Environment and Sustainability, Tsinghua University
Abstract
The global prevalence of geogenically derived cadmium (Cd) enrichment poses significant risks to agricultural sustainability and food security. Micronutrients such as selenium (Se) usually co-occur with Cd in such regions but exhibit low bioavailability in soils, further causing a “hidden hunger” of nutrient depletion in the food supply chain. Through controlled field experiments, we tested strategically designed biochar-based amendments (clay-, manure-, and iron-enriched variants) at 5–20 t ha−1 on limestone-derived paddy soils to synchronously mitigate Cd mobility while enhancing grain Se accumulation. Biochar amendments decreased grain Cd bioaccumulation by 42.3–85.4% and increased grain Se bioaccumulation by 91.6–357.5% across both growing seasons, with a better effect observed in synergy with yield increase in the second growing season, reflecting longer-term soil conditioning and progressive weathering of the amendments. Among the three amendments, BC-ZVI at 10–20 t ha−1 achieved the fastest and most consistent Cd immobilization, lowering grain Cd below the national safety threshold (0.2 mg kg−1) in both growing seasons while increasing grain Se by 91.6–357.5%. BC-Clay and BC-Manure required the second season to reach comparable Cd performance across all application rates. Elevations in soil pH, CEC, and available phosphorus may have accounted for the (im)mobilization effect. Field and literature data further indicated a decoupling between soil total Cd-Se co-enrichment and their mobile or plant-accumulated pools. Findings from this study demonstrate a practical and effective strategy for producing Se-enriched, low-Cd rice in regions with elevated geogenic Cd-Se background. Graphical Abstract
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BibTeX
@article{zhou2026field,
title = {{Field application of biochar-based amendments for safe crop production in karst paddy with a high geological background: Unraveling Cd-Se dynamics}},
author = {Pingfan Zhou and Yuanyuan Xu and Jing Guo and Caide Huang and Rong Su and Deyi Hou},
journal = {Biochar},
year = {2026},
month = oct,
doi = {10.1007/s42773-026-00657-1},
url = {https://doi.org/10.1007/s42773-026-00657-1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Field application of biochar-based amendments for safe crop production in karst paddy with a high geological background: Unraveling Cd-Se dynamics
AU - Pingfan Zhou
AU - Yuanyuan Xu
AU - Jing Guo
AU - Caide Huang
AU - Rong Su
AU - Deyi Hou
PY - 2026
DA - 2026/10/25
JO - Biochar
DO - 10.1007/s42773-026-00657-1
UR - https://doi.org/10.1007/s42773-026-00657-1
AB - The global prevalence of geogenically derived cadmium (Cd) enrichment poses significant risks to agricultural sustainability and food security. Micronutrients such as selenium (Se) usually co-occur with Cd in such regions but exhibit low bioavailability in soils, further causing a “hidden hunger” of nutrient depletion in the food supply chain. Through controlled field experiments, we tested strategically designed biochar-based amendments (clay-, manure-, and iron-enriched variants) at 5–20 t ha−1 on limestone-derived paddy soils to synchronously mitigate Cd mobility while enhancing grain Se accumulation. Biochar amendments decreased grain Cd bioaccumulation by 42.3–85.4% and increased grain Se bioaccumulation by 91.6–357.5% across both growing seasons, with a better effect observed in synergy with yield increase in the second growing season, reflecting longer-term soil conditioning and progressive weathering of the amendments. Among the three amendments, BC-ZVI at 10–20 t ha−1 achieved the fastest and most consistent Cd immobilization, lowering grain Cd below the national safety threshold (0.2 mg kg−1) in both growing seasons while increasing grain Se by 91.6–357.5%. BC-Clay and BC-Manure required the second season to reach comparable Cd performance across all application rates. Elevations in soil pH, CEC, and available phosphorus may have accounted for the (im)mobilization effect. Field and literature data further indicated a decoupling between soil total Cd-Se co-enrichment and their mobile or plant-accumulated pools. Findings from this study demonstrate a practical and effective strategy for producing Se-enriched, low-Cd rice in regions with elevated geogenic Cd-Se background. Graphical Abstract
SN - 2524-7867
SN - 2524-7972
ER -