Implementation of Soil Lime Requirement by a Single-Addition Titration Method.

Buffers for determining a soil's lime requirement (LR) sometimes contain hazardous chemicals. Our objective was to implement a single-addition titration with calcium hydroxide [Ca(OH)2] to determine the LR of soils. The soil pH buffering capacity is calculated from the rise in pH from a single addition of base. The LR is calculated from the soil pH buffering capacity, the target pH, and initial soil pH. The LR of 531 randomly selected client samples determined by single-addition titration were slightly higher than by the Adams-Evans (AE) buffer procedure when LRs were less than 1800 lb per acre. The new procedure recommended about 11% less lime than AE at LRs greater than 1800 lb per acre. Independent evaluations of samples that gave the most widely different LR revealed that the single-addition titration was more accurate and more precise than the AE buffer. [ABSTRACT FROM AUTHOR]