Comparative Study of Selected Soil Properties Following Introduction of Broad‐Leaf Trees into Clear‐Felled Chinese Fir Forest

After clear‐cutting of the first generation Chinese fir (Cunninghamia lanceolata) planted forest, five management models, viz. mixture of Chinese fir and Kalopanax septemlobus (MCK), mixture of Chinese fir and Alnus cremastogyne (MCA), pure Kalopanax septemlobus stand (PKS), pure Alnus cremastogyne stand (PAS), and pure Chinese fir stand (PCS), were established in 1983. The effects of these management models on soil were evaluated by measuring physico‐chemical parameters and soil solution chemistry 20 years after planting. Both broadleaf monocultures and mixtures of broadleaf and conifer exerted a favorable effect on soil fertility. The concentrations of the mainly atmospherically derived ions, including SO4 2−, Cl−, Na+, and Mg2+, were significantly higher under conifer than under broadleafs and under mixtures of broadleaf and conifer. Whereas the concentrations of ions that were mainly controlled within system processes such as K+ and NH4 + varied little among various management models, with the exception of NO3 −, which was significantly higher below PAS than below the others. The concentrations of H+ and Al3+ were also highest under the conifer. In addition, the aerosol sulfate and SO2 deposition did not result in a net loss of base cations (on an area basis) from the broadleaf monocultures and mixtures of broadleaf and conifer. However, slight decreases in forest floor bases were observed under the conifer. The observed evidence from this study also suggests that the principal factor for forest soil acidification may be the N deposition and nitrification of NH4 +, but not S deposition in this region.