Leaching of Saline Calcareous Soil under Laboratory Conditions

Abstract

Soil salinity is a major problem in Kerman pistachio (Pistacia vera) orchards which caused low pistachio’s productivity in recent years. Farmers excessively use gypsum and sulfuric acid amendments to remediate saline soils in their pistachio orchards overcoming this problem. The aim of this study was to investigate type of amendments and the pore volumes of water (PVs) required to efficiently leach excessive salts from saline-calcareous soil. Laboratory experiments were conducted using soil columns that were collected from a pistachio orchard near Kerman city. Four treatments, including irrigation water (control), sulfuric acid, gypsum, and dissolved gypsum were applied to remove salt from these soil columns with using different PVs of water. The concentrations of removed cations and salt from the soil columns were measured by analysis of effluent continuously. The results demonstrated that the effect of chemical amendments in removing soluble salts, sodium, magnesium and calcium was similar to irrigation water and did not differ significantly. Thus, irrigation water removed 62% of the total sodium, 73% of magnesium, and 70% of soluble salts from the soil column up to 1.5 PVs of effluent. Application of chemical amendments was not beneficial to infiltration rate in comparison with irrigation water. Thus, the efficiency of only 1.5 PVs of irrigation water without any amendments can be recommended as the appropriate strategy for practical reclamation of the studied soil.