Soil acidity investigation by potentiometric titrations

Barbara Simon1 -. László Tolner1 – Márk Rékási2 - Erika Micheli1

1Szent István University, Department of Soil Science and Agrochemistry, Gödöllő, Hungary

2Research Institute of Soil Science and Agrochemistry, Budapest, Hungary

Abstract

Potentiometric titration was used to investigate the buffering capacity in the A, E and B horizons of some acid mineral soils (2 Alfisols and 2 Inceptisols) in Hungary. For each horizon, a 0.1 M KOH base solution was added to the soil suspension at 0.025 ml every 0.3 seconds. The leached E horizon showed the highest sensitivity to the basic input. The B horizon showed the lowest sensitivity, in general, probably due to the large amount of clay that accumulated there. In most cases, the organic matter rich A horizon showed medium sensitivity due to the buffering effect of the accumulated organic matter. Results indicate that potentiometric titration is a good method to investigate soil acidity and soil sensitivity.