X-ray photoelectron spectroscopy (XPS) was applied to examine the N structures of soil humic substances and some of their analogues. It was found that for soil humic substances XPS method gave similar results as those...X-ray photoelectron spectroscopy (XPS) was applied to examine the N structures of soil humic substances and some of their analogues. It was found that for soil humic substances XPS method gave similar results as those obtained by 15N CPMAS NMR (cross-polarization magic-angle spinning nuclear magnetic resonance) method. 70%～86% of total N in soil humic substances was in the form of amide, and 6%～13% was presented as amines, with the remaining part as heterocyclic N. There was no difference in the distribution of the forms of N between the humic substances from soils formed over hundreds or thousands of years and the newly formed ones. For fulvic acid from weathered coal and benzoqu inone- (N H-4 )-2 S O-4 polymer the XPS results deviated significantly from the 15N CPMAS NMR data.展开更多
In order to characterize various micromorphologic properties of two forest soils derived from different parent rocks in Lahijan, and use the data collected from micromorphological analysis to interpret dominant pedoge...In order to characterize various micromorphologic properties of two forest soils derived from different parent rocks in Lahijan, and use the data collected from micromorphological analysis to interpret dominant pedogenic processes. Two representative soil pedons, granite （P1） and andesitic basalt （P2） were selected in a mountain landform with northwest aspect. Samples for thin section preparation were taken from each horizon by Kubiena boxes or clods. Micromorphological analysis of soils derived from these two soil pedons in eastern part of Lahijan （northern Iran） were conducted based on the physicochemical and mineralogical data. Micromorphological properties were characterized using a polarized light microscope under plain and cross light. Thin section study indicated that the nature of the parent material clearly affected the content of clay formation. It also showed that clay accumulation in the Bt horizons was not only due to clay illuviation （argillan）, but that strong in situ weathering of primary minerals also contributed to the enrichment of clay in soils derived from andesitic basalt. Comparing the results of clay mineralogy obtained from X-ray diffraction （XRD） with microscopic studies revealed that birefringence fabric （b-fabric） of the groundmass was partly striated due to smectitic minerals in soil of andesitic basalt （Hapludalf）, whereas speckled birefringence fabric was dominant in soil of granite （Udorthent） because of the absence of these minerals. We speculate that pores of skeletal fragments or microcracks in P1 were a place for illuvial clay protection. However, the main factor for flluvial clay film disruption （striation anddeformation） was biological activity （faunal turbation and root pressure） in P1 and expandable minerals and faunal turbation in P2.展开更多
基金Project (No. 39790100) supported by the National Natural Science Foundation of China.
文摘X-ray photoelectron spectroscopy (XPS) was applied to examine the N structures of soil humic substances and some of their analogues. It was found that for soil humic substances XPS method gave similar results as those obtained by 15N CPMAS NMR (cross-polarization magic-angle spinning nuclear magnetic resonance) method. 70%～86% of total N in soil humic substances was in the form of amide, and 6%～13% was presented as amines, with the remaining part as heterocyclic N. There was no difference in the distribution of the forms of N between the humic substances from soils formed over hundreds or thousands of years and the newly formed ones. For fulvic acid from weathered coal and benzoqu inone- (N H-4 )-2 S O-4 polymer the XPS results deviated significantly from the 15N CPMAS NMR data.
基金supported by the Soil Science department, faculty of Agriculture,University of Guilan
文摘In order to characterize various micromorphologic properties of two forest soils derived from different parent rocks in Lahijan, and use the data collected from micromorphological analysis to interpret dominant pedogenic processes. Two representative soil pedons, granite （P1） and andesitic basalt （P2） were selected in a mountain landform with northwest aspect. Samples for thin section preparation were taken from each horizon by Kubiena boxes or clods. Micromorphological analysis of soils derived from these two soil pedons in eastern part of Lahijan （northern Iran） were conducted based on the physicochemical and mineralogical data. Micromorphological properties were characterized using a polarized light microscope under plain and cross light. Thin section study indicated that the nature of the parent material clearly affected the content of clay formation. It also showed that clay accumulation in the Bt horizons was not only due to clay illuviation （argillan）, but that strong in situ weathering of primary minerals also contributed to the enrichment of clay in soils derived from andesitic basalt. Comparing the results of clay mineralogy obtained from X-ray diffraction （XRD） with microscopic studies revealed that birefringence fabric （b-fabric） of the groundmass was partly striated due to smectitic minerals in soil of andesitic basalt （Hapludalf）, whereas speckled birefringence fabric was dominant in soil of granite （Udorthent） because of the absence of these minerals. We speculate that pores of skeletal fragments or microcracks in P1 were a place for illuvial clay protection. However, the main factor for flluvial clay film disruption （striation anddeformation） was biological activity （faunal turbation and root pressure） in P1 and expandable minerals and faunal turbation in P2.
