Horizontal flushing: a promising ameliorative technology for hard saline-sodic and sodic soils

Highly dispersed hard saline-sodic soils are very important agricultural soils in Pakistan and elsewhere in the world. These soils are almost impermeable to infiltrating water. Conventional reclamation procedures using gypsum amendment followed by vertical leaching (GVL) resulted in uneconomical returns from these soils. A technique was developed and evaluated that involved mixing of gypsum with the soil in standing water with a cultivator followed by horizontal flushing of the standing water from the soil surface to a nearby drain and a second flushing repeated after 12 h (GFF). Rice production responded positively to the GFF technology compared to the conventional GVL practice. However, the differences for wheat production and soil reclamation were not so prominent. In a second field experiment, the GFF technique was modified by applying gypsum in between the two water flushings (FGF) and compared to the above mentioned treatments, with (GVL and GFF) or without gypsum (VL and FF). The FGF treatment produced superior results both in terms of soil salinity–sodicity amelioration and crop production.