Influence of Source and Particle Size on Agricultural Limestone Efficiency at Increasing Soil pH

Abstract

Core Ideas Liming materials' fineness affected the effectiveness and economics of lime use. There is little information about pelleted lime's efficiency at increasing soil pH. This study assessed the effectiveness of calcitic and dolomitic agricultural limestone (aglime) particle sizes. Calcitic aglime was more efficient than dolomitic aglime at similar particle sizes. Pelleted lime was more effective than calcitic and dolomitic aglime. The chemico‐physical characteristics of liming materials determine their capacity to neutralize soil acidity. This study evaluated how calcitic and dolomitic agricultural limestone (aglime), pelleted calcitic lime, and different particle sizes of both aglime sources increased soil pH. Both aglime sources were fractionated to pass different Tyler mesh sizes (4–8, 8–20, 20–60, 60–100, or 100+). The equivalent of 8.97 Mg CaCO3 ha–1 of each material or powdered CaCO3 was mixed with three acidic soils and incubated for 7, 21, 35, 70, 105, 140, 175, and 210 d. All sources increased soil pH. Differences among soils were minor compared with source differences. The efficiency of lime sources at raising pH relative to CaCO3 increased with incubation time and fineness, and was lower for dolomitic than for calcitic aglime. Pelleted lime, calcitic aglime, and dolomitic aglime efficiencies across all incubation periods were 60 to 90, 47 to 65, and 12 to 47% respectively. Calcitic aglime's efficiency across the incubation periods was –1 to 29, 17 to 39, 24 to 61, 47 to 81, and 70 to 97% for material passing mesh sizes 4 to 8, 8 to 20, 20 to 60, 60 to 100, and 100+, respectively; whereas dolomitic aglime's efficiency was 2 to 12, 4 to 21, 12 to 43, 50 to 66, and 60 to 86%, respectively. The study demonstrated the value of distinguishing between particle sizes passing mesh sizes 60 to 100 and finer, and between calcitic and dolomitic aglime in aglime assessments and agricultural recommendations.