Abstract
The effects of dry deposition, canopy leaching, precipitation ion concentration, and precipitation H
+
concentration on net throughfall flux (NTF, throughfall minus bulk precipitation) were evaluated on a seasonal basis by using a multiple regression analysis approach based on an observation period of 4 years in Shaoshan subtropical mixed evergreen forest, south-central China. Regression analysis results indicated that the estimated canopy exchange flux was the dominant factor regulating the NTF and the calculated dry deposition was a minor term. The seasonal dry deposition of base cations accounted for 15%-43% of the NTF. The NTF analysis showed that K
+
, Ca
2+
, Mg
2+
, Na
+
, and weak acids in throughfall were derived from foliar leaching and the canopy uptakes of H
+
, NH
4
+
, and NO
3
−
were from precipitation. The retention rate of proton (H
+
and NH
4
+
) in the canopy was close to the canopy leaching rate of base cations when corrected for weak acids because weak acid-induced canopy leaching did not exchange with protons, which suggested that the canopy leaching processes neutralized acid precipitation in Shaoshan forest.