Site description
This study was conducted at the Guanzhuang National Forestry Farm,
Sanming City, Fujian Province, South China (117°43′E, 26°30′N). This
region has a subtropical monsoon climate with a mean annual temperature
ranging from 18.8 to 19.6 °C and a mean annual precipitation ranging
from 1,606 to 1,650 mm (Wu et al. 2013). The Farm contains a
5173-ha
Chinese
fir (Cunninghamia lanceolata ) planation, which was planted in
1992 (Fan et al. 2014). The test soil is classified as a mountain
red soil. Annual average wet N deposition (including soil nitrate and
ammonium nitrogen) resulting from rainfall in the Sanming region was
reported to range from 4.2 to 5.7 g N m-2year-1 (Fan et al. 2014).