ISO 14388-3:20 14规定了一套用于测定酸性硫酸盐土壤净酸度的方法。ISO 14388-3:20 14规定了测定1 mol/l氯化钾土壤悬浮液（pHKCl）pH值的方法，并在需要时测定可滴定的实际酸度（TAA）。随后，测定氯化钾可萃取硫(SKCl)、钙(CaKCl)和镁(MgKCl)。在单独的测试部分上，在用30%过氧化氢消化后，测定过氧化物pH(pHOX)、可滴定过氧化物酸度(TPA)和过量酸中和能力(ANCE)。随后，测定过氧化硫(SP)、钙(CaP)和镁(MgP)。在存在黄钾铁矾或pHKCl<4,5的样品上，在过氧化物消化后剩余的土壤残留物上测定残留酸溶硫（SRAS）。然后通过差值测定可滴定硫化物酸度(TSA)、反应钙(CaA)、反应镁(MgA)和过氧化物可氧化硫(SPOS)。对于含有大量有机硫的泥炭样品，SPOCAS套件通常不适合估计硫化物含量，应使用可还原铬程序套件。

ISO 14388-3:2014 specifies a suite of methods used to determine net acidity in acid sulfate soils. ISO 14388-3:2014 specifies a method for the determination of pH in a 1 mol/l potassium chloride soil suspension (pHKCl) and where required, titratable actual acidity (TAA). Following this, potassium chloride extractable sulfur (SKCl), calcium (CaKCl) and magnesium (MgKCl) are determined. On a separate test portion, following digestion with 30 % hydrogen peroxide, peroxide pH (pH_OX), titratable peroxide acidity (TPA) and excess acid neutralizing capacity (ANC_E) are determined. Following this, peroxide sulfur (S_P), calcium (Ca_P) and magnesium (Mg_P) are determined. On samples where jarosite is present, or where pH_KCl is < 4,5, residual acid soluble sulfur (S_RAS) is determined on the soil residue remaining after peroxide digestion. Titratable sulfidic acidity (TSA), reacted calcium (Ca_A), reacted magnesium (Mg_A) and peroxide oxidizable sulfur (S_POS) are then determined by difference. For peat samples containing substantial levels of organic sulfur, the SPOCAS suite is generally unsuitable for estimating sulfide content, and the chromium reducible suite of procedures should be used instead.