An efficient method for determining the balanced solubility of lime in a predetermined time period

Abstract

The leaching of dissolved calcium (Ca) and magnesium (Mg) carbonates is the main cause for decalcination of soils. The efficiency of various limes in replacing the carbonates and stabilising the available Ca content depends on the dynamics of lime solubility. The latter depends on the material and the size of its particles: the finer the material, the sooner it will dissolve and leach. To reduce the leaching of the Ca into the soil and to stabilise the available Ca content, the particle-size distribution on the basis of the solubility of lime particles with different sizes was determined so that lime would dissolve equally in a balanced way during the anticipated time. While the solubility of limestone particles of different sizes was being assessed in distilled water, the pH of water was brought to 4.0 by adding potassium biphthalate C8H5O4K: it was discovered that the solubility dynamics of all the lime applied to the soil can be controlled by means of its particle-size distribution. In the field trial, the soil contained the available Ca after the application of limestone (particle-size distribution: <0.16 mm 7%, <0.5 mm 25%, <2 mm 76% and <4 mm 93%) both at the beginning of the trial and in its third to fourth year at an equal and optimum level for the growth of field crops (1.50 g kg−1, with the base saturation around 80%). Considering the importance of Ca in soil and the leaching of a notable part of it, it is possible, by means of regulating the limestone solubility dynamics by the particle-size distribution, to improve the resistance of limes to leaching and erosion and to stabilise the Ca content in soil.