Efficiency of Various Agricultural Lime Materials On Georgia Soils.

The University of Georgia Soil, Plant, and Water Laboratory (SPW) uses a  lime recommendation equation that includes a multiplier of 1.5 to account for the less reactivity of agricultural lime (aglime) compared to reagent-grade CaCO₃.  Although research has been conducted with aglime to arrive at this efficiency factor, it has not been conducted using Georgia soils or with aglimes available in Georgia that may differ in their reactivity and purity from others tested previously.  The efficiency of five aglimes commercially marketed in Georgia was compared to reagent-grade CaCO₃ powder on two GA soils with different chemical properties and lime buffering capacities (LBC).  Both soils exhibited an overall increase in pH over the 12-month incubation period, but pH also increased in low LBC soil with no aglime treatment (control). Overall, the final pH values were higher in low LBC soil than high LBC soil. Further evaluation of  aglime efficiency factor in high LBC soil indicated multipliers of 1.17, 1.16, 1.48, 1.34, and 1.73 for aglimes 1 through 5, respectively, with an average multiplier of 1.38.  For practical purposes, a multiplier of 1.5 is suggested.