Molecular determinants of humic and fulvic acids in enhancing micronutrient availability in calcareous soils: a comparative study on Fe, Mn, Zn, and Cu dynamics.

ABSTRACT: Micronutrient deficiencies in calcareous soils, exacerbated by high pH and low organic matter, necessitate sustainable solutions. This study investigated the efficacy of humic (HA) and fulvic acids (FA) in enhancing the availability of Fe, Mn, Zn, and Cu across six calcareous soils, focusing on their molecular properties, application rates, and soil interactions. Purified commercial HA and FA samples were characterized via elemental analysis, FTIR, NMR, and functional group quantification. Incubation experiments assessed DTPA-extractable micronutrients after applying low (12.5 mg/kg) and high (1250 mg/kg) humic substances (HS) rates. Results revealed that conventional application rates of HA and FA had negligible effects (≤ 4-10%). Crucially, high FA application significantly increased Mn

SUBMITTER: Barzgar Z 

PROVIDER: S-EPMC12488940 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature