In order to learn how the organic manure application influences the structural characteristics of humic acids in soils, a comparative study was initiated by the method of 1H-NMR spectra of humic acids separated from the soils (brown soil, meadow soil and paddy soil) with and without organic manure applications (pig manure, corn stalk and rice straw) in field and incubation experiments. The results obtained are summarized as follows:In the solvent system of DMSO-d6, the absorption peaks of 1H-NMR spectra were 0.8, 1.2, 3.4, 3.7, 4.4, 6.7, 7.2 and 8.1 ppm. The absorption peaks of 0.8 and 1.2ppm were the contribution of-CH3 and polymethylene chain(-CH2-)n in saturated hydrocarbons respectively; the signals of 3.4, 3.7 and 4.4ppm were due to the H connected with the carbons in carbonhydrate (α-CH;and the peaks at 6.7, 7.2 and 8.1ppm were generally assigned to aromatic H and-COOH (Ac-H).In the solvent system of NaOH-d1, signals at 1.8, 2.1,and 2.4ppm. were found. It was suggested that these arise from protons attached to carbon a to aromatic ring or other unsaturated groups and α-CH or β-CH in indanes and tetralins of the humic acid.Application of organic manures led to the increase in the relative content of aliphatic H (ali-H).However, the methylene chains (n value) became shorter after organic manure application. On the other hand, the content of aromatic protons (Ar-H) and aromaticity (faH) in humic acids decreased because of organic manure application, which resulted in the increase in the ratio of aliphatic H to Ar-H in the humic acids. Results also showed that pig manure (PM) was more effective than corn stalk (CS) or rice straw (RS) in raising the proportion of aliphatic chain hydrocarbons in humic acids. Whereas CS and RS were more effective in increasing the relative content of carbohydrates in humic acids.
窦森,华士英.施用有机肥料对胡敏酸结构特征的影响─—胡敏酸的1H-核磁共振波谱[J].土壤学报,1997,34(3):225-234. DOI:10.11766/trxb199508210301 Dou Sen, Hua Shiying. EFFECT OF ORGANIC MANURE APPLICATION ON STRUCTURAL CHARACTERISTICS OF HUMIC ACIDS──1H-NMR SPECTRA OF HUMIC ACIDS[J]. Acta Pedologica Sinica,1997,34(3):225-234.复制