Zöttl 1993; Lundström et al. 2003; Löfgren et al. 2009; Moore et al. 2012; Van der
Perre et al. 2012), a 7-year field liming experiment had been carried out at
Tieshanping site. The results showed that both calcite and magnesite application
led to a significant rehabilitation of the acidified soil with increasing trend of pH and
decreasing trend of dissolved Al in soil water (Huang et al. 2014). However, the
addition of calcite may further reduce the availability of Mg
2+ in soil water,
subsequently accelerating depletion of Mg
2+ in the acidified forest soils. Thus, the
effects of liming on the acidified forest soils needs further study.
Acid deposition has been a serious environmental issue in China during the last
decades and is expected to continue in the future, given the continuing economic
development and the increasing fossil fuel consumption. The recovery of acidified
soil and surface water requires additional abatement of emissions of all SO 2 , NO x ,
and NH 3 and applying more effective measures of remediation. In addition, lack of
long-term monitoring results in the impacts of acid deposition, and the acidification
processes of surface waters and soils on a national scale have limited the awareness
of acidification status, buffering mechanisms, and mitigation measures. Thus, more
efforts should be taken in the long-term monitoring.
8.7 Summary
In this chapter we have examined the contribution of N deposition to acid deposition,
the acidification of soil and surface water, buffering processes, and future prospects
of acid rain control. The N deposition has been an increasing contribution to acid
deposition in China in recent decades, and this situation will continue in the future.
So far, the acidification of surface water has seldom been reported, even under
chronically elevated acid deposition in China, especially for areas with acidic
soils. The sharp increase in N deposition has led to only a tiny enhancement of
NO 3
À concentration in surface waters, indicating much less contribution of N
deposition than S deposition to water acidification. On the contrary, soil acidification
has been commonly reported in China, characterized by the decline in soil pH and
the increase in Al mobilization and acid anion leaching. Currently, N deposition
seems to play a more important role in soil acidification than S deposition due to N
transformations, especially in the well-drained soils with low denitrification rate. The
acidification buffering mechanisms are shown to vary from different regions,
depending on climate, deposition characteristics (S, N, and BC deposition), and
soil types. In general, the high BC deposition, rapid weathering rate, and significant
sinks of N and S by denitrification and sulfate adsorption (probably reduction),
respectively, play an important role in acidification buffering under elevated acid
deposition. The reversal of acidification of soil and surface water needs more efforts
in emission abatements of SO 2 , NO x , and NH 3 and applying more effective measures
of acidification remediation in the future.
176
Q. Yu and L. Duan
Perre et al. 2012), a 7-year field liming experiment had been carried out at
Tieshanping site. The results showed that both calcite and magnesite application
led to a significant rehabilitation of the acidified soil with increasing trend of pH and
decreasing trend of dissolved Al in soil water (Huang et al. 2014). However, the
addition of calcite may further reduce the availability of Mg
2+ in soil water,
subsequently accelerating depletion of Mg
2+ in the acidified forest soils. Thus, the
effects of liming on the acidified forest soils needs further study.
Acid deposition has been a serious environmental issue in China during the last
decades and is expected to continue in the future, given the continuing economic
development and the increasing fossil fuel consumption. The recovery of acidified
soil and surface water requires additional abatement of emissions of all SO 2 , NO x ,
and NH 3 and applying more effective measures of remediation. In addition, lack of
long-term monitoring results in the impacts of acid deposition, and the acidification
processes of surface waters and soils on a national scale have limited the awareness
of acidification status, buffering mechanisms, and mitigation measures. Thus, more
efforts should be taken in the long-term monitoring.
8.7 Summary
In this chapter we have examined the contribution of N deposition to acid deposition,
the acidification of soil and surface water, buffering processes, and future prospects
of acid rain control. The N deposition has been an increasing contribution to acid
deposition in China in recent decades, and this situation will continue in the future.
So far, the acidification of surface water has seldom been reported, even under
chronically elevated acid deposition in China, especially for areas with acidic
soils. The sharp increase in N deposition has led to only a tiny enhancement of
NO 3
À concentration in surface waters, indicating much less contribution of N
deposition than S deposition to water acidification. On the contrary, soil acidification
has been commonly reported in China, characterized by the decline in soil pH and
the increase in Al mobilization and acid anion leaching. Currently, N deposition
seems to play a more important role in soil acidification than S deposition due to N
transformations, especially in the well-drained soils with low denitrification rate. The
acidification buffering mechanisms are shown to vary from different regions,
depending on climate, deposition characteristics (S, N, and BC deposition), and
soil types. In general, the high BC deposition, rapid weathering rate, and significant
sinks of N and S by denitrification and sulfate adsorption (probably reduction),
respectively, play an important role in acidification buffering under elevated acid
deposition. The reversal of acidification of soil and surface water needs more efforts
in emission abatements of SO 2 , NO x , and NH 3 and applying more effective measures
of acidification remediation in the future.
176
Q. Yu and L. Duan