PubMed · 2026-06-08
Adding phosphogypsum (a calcium-rich soil amendment) to severely salt-damaged farmland in Ethiopia, combined with a salt-tolerant wheat variety, more than doubled grain yields compared to untreated plots. The optimal combination — phosphogypsum at 150% of the calculated gypsum requirement plus variety ETBW-5879 — also meaningfully reduced soil sodium levels and pH, making the soil healthier long-term.
Applying phosphogypsum at 150–200% of the calculated gypsum requirement reduced soil pH from 8.16 to 7.91–7.93 and cut exchangeable sodium percentage from 34.3% down to 7.9–11.0%.
The combination of phosphogypsum at 200% gypsum requirement with salt-tolerant wheat variety ETBW-5879 increased grain yield by 107% over untreated plots of variety Gambo and by 224% over untreated Dande'a.
Even a lower phosphogypsum rate (100% gypsum requirement) paired with ETBW-5879 outperformed the highest phosphogypsum rate (200%) used with the non-tolerant variety Gambo by 6%, showing that variety choice matters as much as amendment rate.
