Mitigation of sodium risk in a sandy agricultural soil by the use of natural zeolites.

Na+ contamination of irrigation waters represents a global environmental issue for soil structure and plant production. Notwithstanding several techniques for the reduction of Na+ have been proposed in recent years, they generally exhibit disadvantages, including low recyclability and relatively high operational/maintenance costs. In this paper, we propose a natural and eco-friendly solution for the reduction of Na+ risk in coastal agricultural sandy soil (SS), vulnerable to salinity stress. A series of column leaching experiments have been conducted to assess the influence of Italian zeolite-rich tuff (natural zeolites, NZ) addition to soil (NZSS) on Na+ removal, SAR, and CROSS index, under three different salinity scenario. Result showed that the Na+ removal efficiency varied between 46.4 and 54.3% in soil amended with NZ, and analogously SAR index was significantly reduced from 7 to up 13 points. SAR and CROSS indexes resulted better correlated in SS rather than NZSS due to the influence of K+ released by NZ. In conclusion, soil amendment with NZ represents a natural and eco-friendly solution for increasing sandy soil resilience to Na+ risk.