Pedosphere 5(4): 315--323, 1995
ISSN 1002-0160/CN 32-1315/P
©1995 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Fixed ammonium contents and NH4+ fixation capacities of some cultivated soils in China |
| WEN Qi-Xiao, CHENG Li-Li and ZHANG Xiao-Hua |
| Institute of Soil Science, Academia Sinica, Nanjing 210008 (China) |
| ABSTRACT |
| Fixed ammonium contents and NH4+ fixation capacities of some representative cultivated soils collected from 16 provinces of China were studied. Results showed that the contents of fixed ammonium in soils ranged from 35 to 573 mg N kg-1, with an average of 198 mg N kg-1. The content of fixed ammonium correlated very significantly with mica content for tropical and subtropical soils, whereas this was not the case for soils in the temperate zone. At the end of K-exhausting experiment the fixed ammonium content increased in most soils studied. However, it decreased in some temperate soils. Generally, fixation of added NH4+ could not be found either before or after K-exhausting experiment for highly weathered soils, including tropical soils and soils derived from granite-gneiss or Quaternary red clays in the subtropic zone, while for most soils in the Yangtze River dalta the NH4+ fixation capacity was rather high and increased significantly in the K-exhausted soils. |
| Key Words: clay minerals, fixed ammoninm, mica, NH4+ fixation capacity |
| Citation: Wen, Q. X., Cheng, L. L. and Zhang, X. H. 1995. Fixed ammonium contents and NH4+ fixation capacities of some cultivated soils in China. Pedosphere. 5(4): 315-323. |
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