Forecasting of the impact of acidity on the content of mobile forms of potassium in the soils of forest-steppes of Ukraine

Abstract

The level of soil acidity (рН) has the significant impact on availability of potassium to plants. For almost the century, scientists have discussed the issue of acidity of soils. Till nowadays, it is known, that carriers of potential acidity are Н+ and АІ3+ ions, which are situated in the solid phase of soil in the exchanged and absorbed state, but soil solution is acidified as a result of exchange reactions during increase of concentration of electrolytes in it (for example, during application of fertilizes the soil). Our task was to explore the impact of acidity of soil solution on the movement of potassium in some soils of forest-steppes of Ukraine: typical chernozem, podzolized chernozem and meadow chernozem. In the laboratory conditions the soil samples were influenced by citrate-phosphate-borate buffer solution of different volumes of рН – from 2.8 till 9.5 units, and the potassium content was determined by flame photometry. Based on the research results, there were created mathematical models which predict the potassium content when changing soil acidity. An exponential functional relationship between potassium content in the soil solution and its pH is established. This functional dependence allows to predict the levels of transition of potassium to the soil solution in the conditions of lowering the pH.