AMELIORATION OF A BROWN SOLODIZED SOLONETZ SOIL BY A SURFACE APPLICATION OF GYPSUM PLUS AMMONIUM NITRATE

Abstract

Combined applications of ammonium nitrate (449 kg/ha) and gypsum (4.48 tonnes/ha) were added annually to a bromegrass sod for 4 yr. The soil was a Brown Solodized Solonetz with an exchangeable sodium percentage (ESP) of 17 and 33 in the Ap and Bnt horizons, respectively. The significant effects of the combined applications were to reduce exchangeable Na, increase water infiltration and depth of Ca penetration, and provide small increased yields over that of ammonium nitrate alone. Analysis of columnar peds from the Bnt horizon showed that inped penetration of Ca had occurred at the expense of Na. These studies indicate a synergistic effect, whereby the solubility and penetration of gypsum are enhanced by ammonium nitrate.