Microbial mechanisms in nitrogen fertilization : Modulating the re-mobilization of clay mineral-bound cadmium in agricultural soils

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Soil cadmium (Cd) can affect crop growth and food safety, and through the enrichment in the food chain, it ultimately poses a risk to human health. Reducing the re-mobilization of Cd caused by the release of protons and acids by crops and microorganisms after stabilization is one of the significant technical challenges in agricultural activities. This study aimed to investigate the re-mobilization of stabilized Cd within the clay mineral-bound fraction of soil and its subsequent accumulation in crops utilizing nitrogen ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N), at 60 and 120 mg kg-1. Furthermore, the study harvested root exudates at various growth stages to assess their direct influence on the re-mobilization of stabilized Cd and to evaluate the indirect effects mediated by soil microorganisms. The results revealed that, in contrast to the NO3--N treatment, the NH4+-N treatment significantly enhanced the conversion of clay mineral-bound Cd in the soil to NH4NO3-extractable Cd. It also amplified the accumulation of Cd in edible amaranth, with concentrations in roots and shoots rising from 1.7-6.0 mg kg-1 to 4.3-9.8 mg kg-1. The introduction of NH4+-N caused a decrease in the pH value of the rhizosphere soil and stimulated the production and secretion organic and amino acids, such as oxalic acid, lactic acid, stearic acid, succinic acid, and l-serine, from the crop roots. Furthermore, compared to NO3--N, the combined interaction of root exudates with NH4+-N has a more pronounced impact on the abundance of microbial genes associated with glycolysis pathway and tricarboxylic acid cycle, such as pkfA, pfkB, sucB, sucC, and sucD. The effects of NH4+-N on crops and microorganisms ultimately result in a significant increase in the re-mobilization of stabilized Cd. However, the simulated experiments showed that microorganisms only contribute to 3.8-6.6 % of the re-mobilization of clay mineral-bound Cd in soil. Therefore, the fundamental strategy to inhibit the re-mobilization of stabilized Cd in vegetable cultivation involves the regulation of proton and organic acid secretion by crops.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:926

Enthalten in:

The Science of the total environment - 926(2024) vom: 20. Apr., Seite 171809

Sprache:

Englisch

Beteiligte Personen:

Wang, Jun-Feng [VerfasserIn]
Liu, Can [VerfasserIn]
Xu, Zhi-Min [VerfasserIn]
Wang, Fo-Peng [VerfasserIn]
Sun, Yun-Yun [VerfasserIn]
Huang, Jia-Wei [VerfasserIn]
Li, Qu-Sheng [VerfasserIn]

Links:

Volltext

Themen:

00BH33GNGH
Accumulation
Cadmium
Clay
Journal Article
Metabolomic
Metagenomic
Minerals
N762921K75
Nitrogen
Organic Chemicals
Re-mobilization
Soil
Soil Pollutants
T1FAD4SS2M

Anmerkungen:

Date Completed 17.04.2024

Date Revised 17.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.scitotenv.2024.171809

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM370034171