Physico-chemical characteristics of humic substances of major soil associations of Bihar (India) |
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Authors: | B Mishra L L Srivastava |
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Institution: | (1) Department of Soil Science and Agricultural Chemistry, Birsa Agricultural University, 834006 Ranchi, Bihar, India |
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Abstract: | Humic acid (HA) and fulvic acid (FA) extracted from fourteen surface soil samples (0–20 cms) belonging to nine major Soil
Association Groups scattered over different agro-climatic situations, were characterized by elemental and functional group
analysis, E4/E6 ratios, coagulation behaviour and distribution of carbon in different soil humus fractions. The E4/E6 ratio of FA extracted from different soils was wider than that of HA. The coagulation behaviour of HA and FA fractions and
also of cultivated and forest soils showed marked differences. The variations in the ratios of HAC:FAC (0.31 to 1.0) among
different soils were indicative of the degree of humification under the influence of vegetation and agroclimatic conditions.
The elemental composition of HA and FA, in general, indicated a higher carbon and nitrogen content and C/N ratio in the former
than in the latter fraction. On the contrary, the oxygen content of FA was higher compared to that of HA. The carbon contents
of HA extracted from the cultivated and forest soils of Hazaribagh were almost equal, as were also the carbon contents of
HA from the cultivated and forest soils from Ranchi. Total acidity of FA of the soils selected in the present study was higher
than that of HA. The functional groups such as carboxyl, phenolic hydroxyl and carbonyl were present in the two fractions
in varying proportions. |
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Keywords: | coagulation fulvic acid humic acid |
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