4. Soil hydrolytic acidity CH3COONa+H2O- CH3COOH NaoH H-Colloid=Al 4CH3 COoNa- Na-Colloid-3Na Al(oh+4CH COoH Oxide -oH+ Ch CooNa-Oxide-o-Na*+ CH COoH
4. Soil hydrolytic acidity CH3COONa + H2O CH3COOH + NaOH H-Colloid Al + 4CH3COONa Na-Colloid 3Na + Al（OH）3 +4CH3COOH Oxide -OH + CH3COONa Oxide-O-Na++ CH3COOH
表9-2几种土媒中的交换性酸量和水解性酸量的比较 道交换性酸水解性酸 土壤 cd()/kg土 黄壤(厂西)3682 6.81+ 黄壤(四川)206 2.94 黄棕壤〔安徽 0.20 1.97 黄棕(湖北)0 0.44 红壤(广西)1.48 9.14
二、 Soil alkalinity (- The cause of soil alkalinity 1, Calcium carbonate hydrolysis Caco, +H,0 Ca2++HCo3-+OH CO+HO- HCO3-+H 2 Sodium carbonate hydrolysis ()2NaHCO Na.,+,o+co (2)Na2SiO3+ H2CO3- Na2CO3+SiO2+H2O ()CaCO3+NaCl -CaCl2 Na2CO3 CaCO3 Na2SO4 CasO4+ Na2 CO3
二、Soil alkalinity （一） The cause of soil alkalinity 1、Calcium carbonate hydrolysis CaCO3 + H2O Ca2+ + HCO3- + OHCO2 + H2O HCO3- + H+ 2、 Sodium carbonate hydrolysis (1)2NaHCO3 Na2CO3+H2O + CO2 (2)Na2SiO3 + H2CO3 Na2CO3 +SiO2+H2O (3)CaCO3 +NaCl CaCl2 + Na2CO3 CaCO3 + Na2SO4 CaSO4+ Na2CO3
3. Exchangeable Sodium hydrolysis nAt Colloid 2+ 4Na Collo1d2Nat Cat+ 2+ Colloid XNa+yH20+CO2 ColloR y) Nat nAoh ( Affect the factors of soil alklization 1. Climatic factor 2. Biological factor 3. Parent factor
3、 Exchangeable Sodium hydrolysis Ca2+ 2Na+ Mg2+ + 4Na+ 2Na+ + Ca2+ + Mg Colloid Colloid 2+ xNa + yH2O +CO2 （x-y）Na+ + yNaOH yH+ Colloid Colloid （二） Affect the factors of soil alklization： 1．Climatic factor 2．Biological factor 3．Parent factor