Effectiveness of limestone particle size in neutralizing soil acidity

Abstract

Two field microplots experiments were conducted on Haplohumox and Paleudult soils to study the effectiveness of six particle size fractions of commercial limestone in neutralizing soil acidity. Three lime levels were applied and the microplots were fourteen-liter plastic vessels buried at the soil surface level. Soil samples were taken from 3 to 99 months after liming in the Haplohumox soil and from 3 to 78 months in the Paleudult soil to determine: pH in water and in 10-²M KCl extracts. The relative effectiveness (RE) of limestone particles were compared to those of carbonate in neutralizing soil acidity. For particles ranging front 2.00 to 0.84 nun in diameter, RE was 31.5% on average for both soils, considering a two-year-period. For the 0.84 to 0.30 mm fraction the average effectiveness was 68.0%, on the same period, assuming a normal particle size distribution. Limestone particles smaller than 0.30 mm showed on average a 100% effectiveness for both soils.