concentration at almost all monitoring sites has exceeded the threshold of sensitive
plant growth. The results also suggest current O 3 is threatening human health and
ecosystem services. In Chap. 8, Yu and Duan overviewed the contribution of
reactive N to acid deposition, the acidification of soil and surface water,
acidification-buffering processes, and future prospects of acid deposition control in
China. The results indicate N deposition contributed increasingly to acid deposition
in China in recent decades. Surface waters across China are generally not sensitive to
acid deposition, while acidifying effect of N deposition on soil is likely more
important than S deposition due to N transformations.
1.4 The Impact of Nitrogen Deposition on Sensitive
Ecosystems in China
The enhancement of N deposition in China has aroused increasing concerns about its
effect on ecosystem health and function (Du et al. 2015). Forest covers more than
one-fifth of the national land area in China and provides fundamental ecosystem
services. In Chap. 9, Du et al. summarized current understanding of the N deposition
impacts on soil chemistry and N transformation, soil microorganisms and enzymes,
plant physiology and biodiversity, and ecosystem carbon balance in China’s forests.
Experimental results and modeling estimates generally indicate a fertilization effect
of N deposition on forest growth and consequent C sequestration. However, highlevel N deposition has been increasingly evidenced to cause N leaching loss, soil
acidification, nutrient imbalance, increased N 2 O emissions, and decreased soil CH 4
uptake, which likely offsets the positive effect on ecosystem C storage over time.
Meanwhile, N deposition likely changed both species composition and richness of
plant and soil microbial communities in China’s forests.
Grasslands account for 40% of national land area in China and have an essential
role in regional economic development and ecological security. In Chap. 10, Lü et al.
reviewed the impacts of N deposition on China’s grasslands by focusing the changes
of above- and belowground biodiversity and biogeochemical (carbon and nutrient)
cycling. The results indicate that N deposition can substantially increase soil N
availability, alter fluxes of greenhouse gases, and threat plant biodiversity in the
grasslands of China. The impacts of N deposition on other ecosystems, such as
deserts and lakes, were also assessed. In Chap. 11, Zhou X et al. overviewed the
response of China’s desert ecosystems to increasing N deposition. The results
indicate that desert ecosystems are sensitive to increasing N deposition, and the
effect of N deposition is strongly interacted with precipitation. Elevated N deposition
has significantly influenced aquatic ecosystems, especially with regard to their N
budgets and phytoplankton growth potentials. In Chap. 12, Zhou F et al. reviewed
the effect of N deposition on eutrophic lakes by taking Lake Dianchi as an example.
They estimated that annual N deposition accounted for 15.7–16.6% of total N loads
6
X. Liu and E. Du
plant growth. The results also suggest current O 3 is threatening human health and
ecosystem services. In Chap. 8, Yu and Duan overviewed the contribution of
reactive N to acid deposition, the acidification of soil and surface water,
acidification-buffering processes, and future prospects of acid deposition control in
China. The results indicate N deposition contributed increasingly to acid deposition
in China in recent decades. Surface waters across China are generally not sensitive to
acid deposition, while acidifying effect of N deposition on soil is likely more
important than S deposition due to N transformations.
1.4 The Impact of Nitrogen Deposition on Sensitive
Ecosystems in China
The enhancement of N deposition in China has aroused increasing concerns about its
effect on ecosystem health and function (Du et al. 2015). Forest covers more than
one-fifth of the national land area in China and provides fundamental ecosystem
services. In Chap. 9, Du et al. summarized current understanding of the N deposition
impacts on soil chemistry and N transformation, soil microorganisms and enzymes,
plant physiology and biodiversity, and ecosystem carbon balance in China’s forests.
Experimental results and modeling estimates generally indicate a fertilization effect
of N deposition on forest growth and consequent C sequestration. However, highlevel N deposition has been increasingly evidenced to cause N leaching loss, soil
acidification, nutrient imbalance, increased N 2 O emissions, and decreased soil CH 4
uptake, which likely offsets the positive effect on ecosystem C storage over time.
Meanwhile, N deposition likely changed both species composition and richness of
plant and soil microbial communities in China’s forests.
Grasslands account for 40% of national land area in China and have an essential
role in regional economic development and ecological security. In Chap. 10, Lü et al.
reviewed the impacts of N deposition on China’s grasslands by focusing the changes
of above- and belowground biodiversity and biogeochemical (carbon and nutrient)
cycling. The results indicate that N deposition can substantially increase soil N
availability, alter fluxes of greenhouse gases, and threat plant biodiversity in the
grasslands of China. The impacts of N deposition on other ecosystems, such as
deserts and lakes, were also assessed. In Chap. 11, Zhou X et al. overviewed the
response of China’s desert ecosystems to increasing N deposition. The results
indicate that desert ecosystems are sensitive to increasing N deposition, and the
effect of N deposition is strongly interacted with precipitation. Elevated N deposition
has significantly influenced aquatic ecosystems, especially with regard to their N
budgets and phytoplankton growth potentials. In Chap. 12, Zhou F et al. reviewed
the effect of N deposition on eutrophic lakes by taking Lake Dianchi as an example.
They estimated that annual N deposition accounted for 15.7–16.6% of total N loads
6
X. Liu and E. Du