Work

High manganese levels promote soil ammonium nitrogen accumulation but suppress plant nitrogen uptake

Year: 2026

Type: article

Abstract: Manganese ion (Mn(Ⅱ)) toxicity in acidic soils is a global agricultural and environmental issue that severely constrains crop productivity and soil ecosystem functioning. Systematic understanding of the effects of Mn(Ⅱ) stress on soil nitrogen (N) transformation processes and their underlying mechanisms remains limited. A short-term pot experiment using sugarcane (Saccharum officinaru250-wordm) was conducted to investigate the effects of varying Mn(Ⅱ) concentrations on sugarcane N uptake, soil N transformation processes, and the underlying microbial mechanisms. High Mn(Ⅱ) concentrations (≥ 900 mg·kg⁻¹) significantly inhibited N uptake in sugarcane, reducing plant N accumulation by approximately 50%. Elevated Mn(Ⅱ) levels stimulated soil urease activity but suppressed ammonia monooxygenase (AMO) activity and nitrification potential. Concurrently, the concentration of soil soluble organic nitrogen dropped from 88.46 to 20.78 mg kg⁻¹ , whereas ammonium nitrogen (NH₄⁺-N) rose from 3.29 to 14.50 mg kg⁻¹ . This divergence suggests that nitrification was suppressed, leading to the accumulation of NH₄⁺-N. The α-diversity index of the soil bacterial community exhibited a U-shaped response to increasing Mn(Ⅱ) concentrations, although its composition remained relatively stable. Ammonia-oxidizing archaea (AOA) showed greater OTU richness and diversity than the ammonia-oxidizing bacteria (AOB). AMO activity correlated negatively with Nitrososphaera abundance but positively with Nitrosospira abundance. With increasing Mn(Ⅱ), Nitrosospira declined progressively while the tolerant genus Nitrosovibrio became dominant, reflecting community shifts under Mn stress. High Mn(Ⅱ) levels thus reshaped the AOB community structure, suppressed nitrification, and reduced plant N uptake efficiency. These findings offer a theoretical basis for improving nitrogen management and ecological remediation in Mn-contaminated acidic farmlands.

Source: Ecotoxicology and Environmental Safety

DOI: 10.1016/j.ecoenv.2026.120402

Authors: Jinlan Huang, Wenqiang Chen, Ziang Zhao, Yin Liang, Xuejiao Huang, Xiaofeng Li

Institutions: Guangxi University, State Key Laboratory For Conservation and Utilization of Subtropical Agro-Bioresources

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Zero hunger, Life on land

Open Access status: gold

Estimated APC paid: $3,650