ISSN:
1573-5036
Keywords:
Black soil
;
Extractant
;
Humic substances
;
Laterite Soil
;
Metal-organic-complex
;
Polymer
;
Primary minerals
;
Red Soil
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Effect of sources, moisture levels and extractants on extraction, analytical properties, IR-spectra, macromolecular characteristics, interaction with cations and physiological properties of the extracted material (humic acid) were studied. Among the three variables, extractant influenced the degree of humification, IR-spectra, nature and properties of humic acids to a greater extent though the other two had significant contribution. Sodium pyrophosphate found to be an ideal extractant for humic acid. Reduced viscosity of humic acids increased with dilution particularly below 0.1 g/dl and decreased with increasing H+ concentration between pH 6.5 and 8.5 irrespective of source, moisture level and extractant. The amount of proton released and drop in initial pH of humic acids on addition of different metal ions indicated formation of mono-, di-hydroxy metal-HA complexes which broke down at pH 8.0 and above. HA-Fe2+ and HA-Cu2+ complexes were found to be most stable. Humic acids from different sources varied significantly in their effect on available nutrient status of soils though, the latter is main determining factor particularly for calcium and magnesium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02140667
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