Buffer pH

Buffer pH (also called lime buffer capacity) is determined by mixing soil with a buffering solution and measuring the resulting pH. While soil pH tells you how acidic the soil currently is, buffer pH reveals the soil's resistance to pH change — essentially how much lime is required to correct the acidity. Soils with high organic matter or clay content have greater buffering capacity and require more lime per unit of pH change. Common buffer methods include the SMP, Sikora, and Woodruff procedures, with the choice varying by region. Buffer pH is indispensable for making accurate lime recommendations and avoiding both under- and over-liming.