Seasonal dry deposition and canopy leaching of base cations in a subtropical evergreen mixed forest, China.

摘要

We evaluated the dry deposition and canopy leaching fluxes of base cations in the growing and the dormant seasons using the Na-ratio method based on the 4-year (2000–2003) monitoring data in Shaoshan subtropical evergreen mixed forest, China. The dry deposition of base cations in the growing seasons was lower than that in the dormant seasons, while the canopy leaching of base cations was higher in the growing seasons than that in the dormant seasons. The precipitation quantity and H+ significantly impacted the canopy leaching processes. The annual canopy leaching of K+, Ca2+ and Mg2+ accounted for 88, 46 and 38% of net throughfall flux, respectively. The canopy retention of proton (H+ and NH4+) is close to the canopy leaching of base cations calibrated by weak acids, indicating that the canopy cations leaching is neutralizing acid precipitation.