Table 2. Characteristics of soil used in this study.

Characteristics	Forest soil
pH [H2O]	4.9
pH [KCl]	4.2
Electric conductivity (mS/m)	5.4
Total carbon (%)	11
Total nitrogen (%)	0.68
Total humic substance (%)	19
Total phosphorus content (mg/kg)	1,100
Available phosphorus content (mg/kb)	2.0
Exchangeable cations
K (cmol (+)/kg)	0.48
Mg (cmol (+)/kg)	1.0
Ca (cmol (+)/kg)	3.8
Na (cmol (+)/kg)	0.096
Mn (cmol (+)/kg)	0.031
Al (cmol (+)/kg)	0.96