A modification to Schoonover's method of gypsum requirement determination of soil

Abstract

During laboratory studies it was noted that water-soluble carbonate plus bicarbonate interferes with the determination of gypsum requirement (GR) by Schoonover's method and has significant correlation with the latter (r = 0.89). The interference of carbonate and bicarbonate can be eliminated through their precipitation as magnesium carbonate. A modified method to this effect is suggested hereby, and values of GR determined by this method are quite close (r = 0.99) to those of exchangeable sodium and give a fair approximation to it.