Contribution to the identification of solution for the remediation of salt-affected soils of the high valley of Cochabamba in Bolivia : use of Gypsum, Sulphur and Suaeda foliosa

Abstract

Salt-affected soils can be found throughout the continents and are a major issue for agriculture. In order to evaluate the potential of rehabilitation of saline-sodic soils in the High Valley of Cochabamba in Bolivia, three different remediation techniques were tested: two by chemical amendments, gypsum and sulphur, and one by phytoremediation with the native halophyte Suaeda foliosa. An experiment was carried out in pots containing saline-sodic soil in a greenhouse to evaluate the effect of these management techniques on the saline properties of the soil. Two different doses of the gypsum requirement (GR) and sulphur requirement (SR) were tested, 100% of the GR/SR and 50% of the GR/SR. As for the phytoremediation treatment plants of 1-2 months and of 3-4 months were put to trial. Treatments with chemical amendments managed to decrease Exchangeable Sodium Percentage (ESP) from 70% down to 27%, 43%, 52% and 58% for the 100% - GR, 50% - GR, 100% - SR and 50% - SR respectively. For all the chemical treatments, the electrical conductivity (EC) was reduced by more than 50% and the pH was significantly reduced. Even though, EC, pH and ESP was reduced after the chemical amendment treatments, they are still above the threshold values for the soil to be characterised as non-saline-sodic. The results for the phytoremediation treatments weren’t as promising with increased values of ESP and EC. A longer-term experiment should be carried out to continue the evaluation of the reclamation by chemical amendments and the phytodesalination capacity of Suaeda foliosa.