An Integrated Approach to Remediate Saline Soils and Mining Waste Using Technosols and Pasture Development

Reclaiming marginal lands such as saline soils or mining waste for livestock grazing through Technosols and phytostabilisation can provide a solution to the growing food demand. This study evaluated the enhancement of soil properties by two Technosol constructions, along with pasture development. The experimental set-up consisted of gossan waste (G), Fluvisol (VF), Technosol/gossan (TG), and Technosol/Fluvisol (TVF), both Technosols consisting of G and VF, respectively, mixed with organic and inorganic amendments. These substrates were sown in pasture in pots (1.5 dm3) that was cut one and two months after sowing to simulate grazing. Both Technosols improved soils properties, with the acidity of G neutralising in TG. Yet, in TVF, a 65% reduction in salinity and a 60% drop in exchangeable Na occurred compared with VF. Nutrient pool, aggregate stability, and microbiological activity were also improved. Dehydrogenase activity was practically 0 in G, while in TG it was 15 times higher, and with pasture it increased 6-fold. In FV, some activity was already present, but in TVF it was six times higher and even increased with pasture. Finally, these improvements allowed the establishment of a healthy pasture, with twice the biomass and less accumulation of potentially hazardous elements in TG, and considerable growth in TVF. Thus, the co-application of Technosols and pasture may be effective in converting marginal lands into productive areas (grazing, foraging, biomass energy).