四、 Adjustment of Soil acid- alkali and redox (- Adjustment of soil acidity The soil acidity can be adjusted by lime. The lime can be divided by three main categories, which are Calcium oxide(CaO), Calcium hydroxide ca(oh and Calcium carbonate(CacO3) 2+H0 HCO Ca(oh:+ 2H cO, P Ca(HCo,)+ 2H-0u caCO2+HCO2→Ca(HCO2) (9-51) 胶粒 H'+Ca(oH) 胶粒=ca+2H04 H ae A 胶粒 +a0m胶粒ca+210m)2 A Cas四、Adjustment of Soil acid-alkali and redox （一）Adjustment of soil acidity The soil acidity can be adjusted by lime. The lime can be divided by three main categories, which are Calcium oxide (CaO), Calcium hydroxide [Ca(OH)2 ] and Calcium carbonate(CaCO3 )