『Abstract
A sequential dissolution technique and a prolonged extraction
method were used to investigate aluminium (Al) release from 4
Haplic Acrisols in southeastern China. The results show that the
order of acidification of the 4 soils is: Tunxi soil＞Yongchun
soil＞Shengxian soil＞Ninghai soil. The amount of exchangeable Al
is directly proportional to the extent of soil acidification.
Al was released from both organically bound and inorganic Al pools
after acid input. During several initial cycles of extraction
the release of Al was mainly from the weakly organically bond
Al pool. After prolonged extraction, Al release from the inorganic
Al pool became more important to the total dissolved Al due to
a rapid depletion of the weakly organically bound Al pool. The
sizes of readily reactive Al pools in the Ninghai soil and Shengxian
soil are larger than in the Yongchn soil and Tunxi soil. Al released
from the inorganic Al pool in the Ninghai soil, Shengxian soil
and Yongchun soil after 20 cycles of extraction was higher than
from the organically bound Al pool, whereas the opposite was the
case for the Tunxi soil. A low saturation of Al binding on soil
organic matter (SOM) does not necessarily lead to a low Al release
as in the case of the Shengxian soil. Also a relatively high saturation
does not necessarily ensure a large Al release from the Al pool
as in the case of the Tunxi soil and Yonchun soil. Once both organically
bond and inorganic Al pools are depleted of readily reactive Al
phases due to high soil acidification, Al dissolution would be
small even under strong acid input. The high concentration of
aqueous Al after rapid Al release from the weakly organically
bound Al pool and subsequent depletion of the pool may have significant
ecological and environmental effects.』
1. Introduction
2. Materials and methods
2.1. Soils
2.2. Methods and analytical procedures
3. Results and discssion
3.1. AlKCl
3.2. Alp and Alox
3.3. ΔAlp and ΔAlox
3.4. The influence of mobility and depletion of Al pool on Al
release
3.5. Environmental implications of different mobilities of Al
pools
4. Conclusion
Acknowledgements
References