Chemical Composition and Structural Characteristics of Humic Acids Extracted from Organic Fertilizers Composted by Different Materials

the chemical composition and structure characteristics of humic acid in three kinds types of organic fertilizers (T1, corn stalk:cow dung:rapeseed cake=60:50:30; T2, corn stalk:tobacco waste:cow dung:rapeseed cake=35:25:40:30; T3, tobacco stem:tobacco waste:pig dung:rapeseed cake=30:30:40:30) are were studied using elemental analysis, Ffourier transform infrared spectroscopy (FT IR), solid ¹³C nuclear magnetic resonance (NMR) and electron microscope scanning. The results showed that (1) C, H, N, O contents of organic humic acid were in T3 > in T2 > in T1; (2) The FT-IR analysis showed that H-H and benzene H in humic acid in T3 were higher than> in T1 and T2. The absorption intensity at 1050 cm^-1 of T2 is was relatively strong. Absorption intensity at 1710 cm^-1 of the T3 sample is was the most strongest among the 3 treatments, which containing the most carboxyl and carbonyl functional groups. (3) The solid ¹³C-NMR analysis results showed that the fat content of carbon (δ0~50) in T3 and the carbon oxygen fat (δ50~110) content in T1 and the aromatic carbon (δ110~160) content in T2 arewere the highest among the three treatments respectively, and that the carboxyl and carbonyl (δ160~230) carbon contents were in T3=in T2 > in T1; (4) the The electron microscope scanning results showed that there are were vascular structures and space surfacepores on the surface of humic acid particles, with the number of vascular structures of T3 > of T2 > of T1, and the number of gap pores in the reversed orderon the contrary. In summary, significant difference was observed inThe results showed that the chemical composition and structure characteristics of the three kinds types of humic acid has obvious difference.