Sorption of vapors of some organic liquids on soil humic acid and its relation to partitioning of organic compounds in soil organic matter

1988 ◽  
Vol 22 (3) ◽  
pp. 298-303 ◽  
Author(s):  
Cary T. Chiou ◽  
Daniel E. Kile ◽  
Ronald L. Malcolm
2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.


RSC Advances ◽  
2014 ◽  
Vol 4 (45) ◽  
pp. 23658-23665 ◽  
Author(s):  
A. Nebbioso ◽  
A. Piccolo ◽  
M. Lamshöft ◽  
M. Spiteller

Humeomics encompasses step-wise chemical fractionation and instrumental determination to fully characterize the heterogeneous molecular composition of natural organic matter.


1991 ◽  
Vol 46 (11-12) ◽  
pp. 982-988 ◽  
Author(s):  
R. Fründ ◽  
H.-D. Lüdemann

Abstract In a systematic study the organic carbon content of typical Germ an soils was studied by solid state C-13 CPM AS spectroscopy.In order to check the quantitative validity of the standard sodium hydroxide extraction procedure, which fractionates soil organic matter into hum in, humic acid, and fulvic acid also the high resolution solid state spectra of these fractions were determined.The chemical information obtained from these spectra is discussed.


2019 ◽  
Vol 99 (2) ◽  
pp. 195-207 ◽  
Author(s):  
Yu Tan ◽  
Wanqin Yang ◽  
Xiangyin Ni ◽  
Bo Tan ◽  
Kai Yue ◽  
...  

The formation of soil organic matter via humification of plant litter is important for long-term carbon sequestration in forests; however, whether soil fauna affects litter humification is unclear. In this study, we quantified the effects of soil fauna on the optical properties (i.e., ΔlogK and E4/E6) of the alkaline-extracted humic acid-like solutions of four foliar litters by removing soil fauna via litterbags with different mesh sizes in two subtropical evergreen broad-leaved forests. Litterbags were collected at the leaf falling, budding, expanding, maturation, and senescence stages from November 2013 to October 2015 to assess whether the effects of soil fauna on litter humification vary in different plant phenology periods. The results showed that soil fauna significantly reduced the ΔlogK and E4/E6 values in the leaf expanding stage of oak litter and in the leaf falling stage of camphor and fir litters. The richness index of soil fauna explained 21%, 55%, 19%, and 45% of the variations in the E4/E6 values for oak, fir, camphor, and pine litters, respectively. The effects of litter water content on these optical properties were greater than that of temperature. These results indicated that soil fauna plays a key role in litter humification in the leaf expanding and falling stages and are potentially involved in soil carbon sequestration in these subtropical forests.


Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 337-353 ◽  
Author(s):  
Femke H Tonneijck ◽  
Johannes van der Plicht ◽  
Boris Jansen ◽  
Jacobus M Verstraten ◽  
Henry Hooghiemstra

Volcanic ash soils (Andosols) may offer great opportunities for paleoecological studies, as suggested by their characteristic accumulation of organic matter (OM). However, understanding of the chronostratigraphy of soil organic matter (SOM) is required. Therefore, radiocarbon dating of SOM is necessary, but unfortunately not straightforward. Dating of fractions of SOM obtained by alkali-acid extraction is promising, but which fraction (humic acid or humin) renders the most accurate 14C dates is still subject to debate. To determine which fraction should be used for 14C dating of Andosols and to evaluate if the chronostratigraphy of SOM is suitable for paleoecological research, we measured 14C ages of both fractions and related calibrated ages to soil depth for Andosols in northern Ecuador. We compared the time frames covered by the Andosols with those of peat sequences nearby to provide independent evidence. Humic acid (HA) was significantly older than humin, except for the mineral soil samples just beneath a forest floor (organic horizons), where the opposite was true. In peat sections, 14C ages of HA and humin were equally accurate. In the soils, calibrated ages increased significantly with increasing depth. Age inversions and homogenization were not observed at the applied sampling distances. We conclude that in Andosols lacking a thick organic horizon, dating of HA renders the most accurate results, since humin was contaminated by roots. On the other hand, in mineral soil samples just beneath a forest floor, humin ages were more accurate because HA was then contaminated by younger HA illuviated from the organic horizons. Overall, the chronostratigraphy of SOM in the studied Andosols appears to be suitable for paleoecological research.


2015 ◽  
Vol 39 (4) ◽  
pp. 1068-1078 ◽  
Author(s):  
José Alberto Ferreira Cardoso ◽  
Augusto Miguel Nascimento Lima ◽  
Tony Jarbas Ferreira Cunha ◽  
Marcos Sales Rodrigues ◽  
Luis Carlos Hernani ◽  
...  

Improper land use has lead to deterioration and depletion of natural resources, as well as a significant decline in agricultural production, due to decreased soil quality. Removal of native vegetation to make way for agricultural crops, often managed inadequately, results in soil disruption, decreased nutrient availability, and decomposition of soil organic matter, making sustainable agricultural production unviable. Thus, the aim of the present study was to evaluate the impact of growing irrigated mango (over a 20 year period) on the organic carbon (OC) stocks and on the fractions of soil organic matter (SOM) in relation to the native caatinga (xeric shrubland) vegetation in the Lower São Francisco Valley region, Brazil. The study was carried out on the Boa Esperança Farm located in Petrolina, Pernambuco, Brazil. In areas under irrigated mango and native caatinga, soil samples were collected at the 0-10 and 10-20 cm depths. After preparing the soil samples, we determined the OC stocks, carbon of humic substances (fulvic acid fractions, humic acid fractions, and humin fractions), and the light and heavy SOM fractions. Growing irrigated mango resulted in higher OC stocks; higher C stocks in the fulvic acid, humic acid, and humin fractions; and higher C stocks in the heavy and light SOM fraction in comparison to nativecaatinga, especially in the uppermost soil layer.


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