Study of extracted humic acid from the soil of Naharhoran forest in Gorgan

Humic acid is a fertilizing factor of soil. Its composition and actual structure, however, has been unknown up to now. The objective of this present investigation is the study the humic acid structure. In this study, the humic acid was extracted from the soil of a forest in north Iran, according to IHSS protocol. The IR spectrum of this sample was in complete agreement with that of J.L. Gardea. Furthermore, the existence of benzoic-carboxyl and phenol functional groups in it was confirmed. GC-MS analysis showed its structural composition. The XRD pattern of this humic acid indicated the presence of amorphous phases in the sample containing particles. The scanning electronic microscopy image revealed the size of these particles to be about 0.20 mu m. Thermal analysis of the sample (TG and DSC) provided the complementary information about its structure. The CHNS experiments indicated that the extracted humic acid from the soil of Naharhoran forest in Iran contained fertilizing factor.