Vegetation uptake of nitrogen and base cations in China and its role in soil acidification.
Vegetation uptake of nitrogen and base cations may be an important source of soil acidity. In this study, the uptake rate of nitrogen and base cations was estimated for each major vegetation type in China. Although the uptake rates of most vegetation types are lower than 2.0 keq ha(-1) a(-1), great variations exist because of the significant differences in net primary productivity and elemental composition. Uptake rates decreased gradually from southeast to northwest, except for the wide-distributed agricultural areas in the east of China, where the nitrogen and base cation uptake rates are near zero. It is evident that this pattern coincides well with the distribution of the annual mean precipitation. However, the geographical distribution of the base cation uptake rate is not entirely the same as that of nitrogen, which indicates the importance of soil conditions in determining the chemical component and hence the uptake rate of different vegetation. The acidity input caused by vegetation uptake is quite high (>0.5 keq ha(-1) a(-1)), and even higher than the current acid deposition and the alkalinity produced by soil weathering in some areas, which indicates that the growth of the plants may contribute significantly to the soil acidification problem in China.
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, PR China. lduan@tsinghua.edu.cn
Lei
L
Duan
Yongmei
Y
Huang
Jiming
J
Hao
Shaodong
S
Xie
Min
M
Hou
D002681:China; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000737:chemistry / Q000493:pharmacokinetics*; D063245:Plant Development; D012987:Soil
D012987:Soil; D009584:Nitrogen