Reclamation of a saline/sodic soil by aquifer pumping, application of tillage and gypsum and reuse of saline groundwater

摘要

In the Goulburn Valley, at a site near Tongala, Vic., shallow perched watertables receded from 18 to 135 cm below the surface and the piezometric pressure was reduced from 16 to 180 cm below the surface in a saline/sodic soil 3 months from the start of pumping. Consequently soil salinity was reduced from ECe 12.3 to 7.3 dS/m in the top 30 cm under 1 15 mm ofrainfall. Further reduction in salinity to ECe 3 dS/m was achieved after 19 months. The presence of electrolytes in irrigation water preserved soil permeability during the irrigation season, while gypsum was beneficial during the winter rainfall season. Perennial pasture was established 11 months after pumping commenced. Weeds that originally dominated the site disappeared, while clover produced 70% of total dry matter.