Long-term field experiment was established in 1978 on a coastal paddy soil to determine the effect of applicationof pig manure, rice straw and chemical N fertilizer on the physical property and humus characteristics o...Long-term field experiment was established in 1978 on a coastal paddy soil to determine the effect of applicationof pig manure, rice straw and chemical N fertilizer on the physical property and humus characteristics of soil . Resultsshowed that the porosity, the microstructural coefficient, the reactivities of organic C and N, the ΔlogK value, thedegree of oxidation stability, the contents of O-alkyl C and alkyl C, and the ratio of aliphatic C to aromatic C ofhumic acid from soils received organic manure increased, whereas, the ratio of < 10 μm to >10 μm ofmicroaggregates, the humification degree of humus, the degree of organo-mineral complexation, the number-averagemolecular weight, the C/ H ratio. the contents of carboxyl and aromatic C of HAs in them decreased. These resultsindicated that the application of organic manure not only improved the physical property of the paddy soil but alsomade the HA more aliphatic in structure and younger in origin.展开更多
Chemical characteristics of humic substances in soils with different mineralogical characteristics and under different utilization patterns in Zhangpu, Fujian Province,together with two pairs of cultiwted soils in Nor...Chemical characteristics of humic substances in soils with different mineralogical characteristics and under different utilization patterns in Zhangpu, Fujian Province,together with two pairs of cultiwted soils in North China Plain were studied by chemical analysis,visible and IR spectroscopy and 13C NMR spectrometry.For soils in Zhangpu the HA/FA ratio and both the aromaticity and the degree of hundfication of HA were higher in soils with montmorillonite as the predominant clay mineral than in thO6e with kaolinite as the predominant clay mineral, provided these soils were under the same utilisstion pattern. While for eaCh pair of soils with similar mineralogical characteristics the HA/FA ratio was higher and the C/H ratio and the content of carboxyl group of HA were lower in paddy soil than in upland soil.Among the upland soils(or paddy soils) studied the HA/FA ratio of soil in Zhangpu with kaollnite as the predominant clay mineral was the lowest,and that of soil in Zhangpu with montmorillonite aa the predominant clay mineral was the highest.It was concluded that the presence of moatmorillonite favored the formation and maturation of humic acid.展开更多
Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize diffe...Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.展开更多
文摘Long-term field experiment was established in 1978 on a coastal paddy soil to determine the effect of applicationof pig manure, rice straw and chemical N fertilizer on the physical property and humus characteristics of soil . Resultsshowed that the porosity, the microstructural coefficient, the reactivities of organic C and N, the ΔlogK value, thedegree of oxidation stability, the contents of O-alkyl C and alkyl C, and the ratio of aliphatic C to aromatic C ofhumic acid from soils received organic manure increased, whereas, the ratio of < 10 μm to >10 μm ofmicroaggregates, the humification degree of humus, the degree of organo-mineral complexation, the number-averagemolecular weight, the C/ H ratio. the contents of carboxyl and aromatic C of HAs in them decreased. These resultsindicated that the application of organic manure not only improved the physical property of the paddy soil but alsomade the HA more aliphatic in structure and younger in origin.
文摘Chemical characteristics of humic substances in soils with different mineralogical characteristics and under different utilization patterns in Zhangpu, Fujian Province,together with two pairs of cultiwted soils in North China Plain were studied by chemical analysis,visible and IR spectroscopy and 13C NMR spectrometry.For soils in Zhangpu the HA/FA ratio and both the aromaticity and the degree of hundfication of HA were higher in soils with montmorillonite as the predominant clay mineral than in thO6e with kaolinite as the predominant clay mineral, provided these soils were under the same utilisstion pattern. While for eaCh pair of soils with similar mineralogical characteristics the HA/FA ratio was higher and the C/H ratio and the content of carboxyl group of HA were lower in paddy soil than in upland soil.Among the upland soils(or paddy soils) studied the HA/FA ratio of soil in Zhangpu with kaollnite as the predominant clay mineral was the lowest,and that of soil in Zhangpu with montmorillonite aa the predominant clay mineral was the highest.It was concluded that the presence of moatmorillonite favored the formation and maturation of humic acid.
文摘Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.
