Pedosphere 1(3): 229--239, 1991
ISSN 1002-0160/CN 32-1315/P
©1991 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Characteristics of Humic Substances in Paddy Soils
Department of Soil Biochemistry, Institute of Soil Science, A cademia Sinica, P.O.Box 821, Nanjing
      In the present paper, the composition of humus and the charateHstics of humic acid from seven paddy soils were compared with those of upland (and/or natural) soils. Results show that :(1) in each group of the soil samples for comparison the HA/FA ratio of the humus of a paddy soil, in most cases, was appreciably higher than that of adjacent upland (and/or natural) soil derived from the same parent material; (2) the humic acid extracted from the paddy soils was characterized by a higher C/O ratio, a higher content of methoxyl groups, and a lower content of carboxyl groups than those from the corresponding upland (and/or natural) flooded soils, implying that the humic acid formed under rice cultivation is in a lower degree of humification than that formed under upland (and/or natural) conditions; and (3) the humic acid of paddy soils, however, was not always characterized by a lower aromaticity than that of the corresponding upland (and/or natural) soils.
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Citation: Ye, W. and Wen, Q. X. 1991. Characteristics of Humic Substances in Paddy Soils. Pedosphere. 1(3): 229-239.
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