PONTO DE EFEITO SALINO NULO E CARGAS ELÉTRICAS DE SOLOS DO ESTADO DA PARAÍBA

Abstract

The soil fertility and plant nutrition are influenced by electrochemical reactions occurring on the surface of soil colloids. The point of zero salt effect (PZSE) is an important parameter to study the surface charge of those colloids, since, it allows to determine the net surface charge of soil particles. This paper aimed to determine the PZSE and the net electrical charge of twelve soils from Paraíba State, which samples were collected at the depth of 0-30 cm. The point of zero salt effect was determined using program computational PZSE for Windows version 1.0. The method adopted was the potentiometric titration with different ionic strength using electrolyte NaCl in concentrations 0.1; 0.01 and 0.001 M. The use of the program has a better analysis and accuracy of the values obtained for the PZSE, which ranged from 3.06 to 5.41. All soils had values of PZSE smaller than the pH in water, being, therefore, electronegative. All soils had the potential and the electrical charge negative, possibly due to the effect of organic matter once it presented significant correlation with PZSE.