Table 1 Chemical properties of humic acids
From: Potential alteration of iron–humate complexes by plant root exudates and microbial siderophores
Sample | C (%) | H (%) | N (%) | Ash (%) | Acidity (meq g−1) | Complexed Fe (%) | ||
|---|---|---|---|---|---|---|---|---|
Total | Carboxyl | Phenolic | ||||||
HA1 | 50.8 | 4.2 | 2.3 | 1.0 | 10.7 | 4.7 | 6.0 | 7.57 |
HA2 | 64.2 | 3.5 | 1.5 | 1.5 | 9.3 | 4.4 | 4.9 | 6.83 |