三、 Affect the factors of soil acidity 1 Base saturation 2, CO2 differential pressure in the soil air 3 Soil moisture content 4 Condition of soil redox Acid soil (yunnan Province People s Republic of China)三、 Affect the factors of soil acidity 1,Base saturation 2, CO2 differential pressure in the soil air 3, Soil moisture content 4, Condition of soil redox Acid soil (Yunnan Province, People's Republic of China)