Pedosphere 6(1): 39--45, 1996
ISSN 1002-0160/CN 32-1315/P
©1996 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Formation and water stability of aggregates in red soils as affected by organic matter |
| ZHANG Ming-Kui1, HE Zhen-Li1, CHEN Guo-Chao1, HUANG Chang-Yong1 and M. J. WILSON2 |
1 Department of Land Use and Applied Chemistry, Zhejiang Agricultural University, Hangzhou 31O029 (China)
2 Soils and Soil Microbiology Division, Macaulay Land Use Research Institute, Aberdeen, AB9 2QJ (UK) |
| ABSTRACT |
| The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements, and the mechanisms responsible for the formation of water-stable soil aggregates were studied. The results showed that the water stability of soil aggregates declined with increasing size, especially for the low organic matter soils. Organic matter plays a key role in the formation of water-stable soil aggregates. The larger the soil aggregate size, the greater the impact of organic matter on the water stability of soil aggregates. Removal of organic matter markedly disintegrated the large water-stable aggregates (> 2.0 mm) and increased the small ones (< 0.25-0.5mm) to some extent, whereas removal of free iron(aluminium) oxides considerably destroyed aggregates of all sizes, especially the < 0.25-0.5 mm classes. The contents of organic matter in water-stable aggregates increased with aggregate sizes. It is concluded from this study that small water-stable aggregates (< 0.25-0.5 mm) were chiefly cemented by Fe and Al oxides whilst the large ones (> 2.0 mm) were mainly glued up by organic matter. Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils. |
| Key Words: aggregate, free oxides, organic matter, red soil, water stability |
| Citation: Zhang, M. K., He, Z. L., Chen, G. C., Huang, C. Y. and Wilson, M. J. 1996. Formation and water stability of aggregates in red soils as affected by organic matter. Pedosphere. 6(1): 39-45. |
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