TITLE:
Monitoring the Effect of Phosphogypsum Amendment Combined with Cow Manure on the Restoration of Saline Soils: The Case of the Kobongoye Rice Valley, in the Municipality of Fimela, West-Central Senegal
AUTHORS:
Jean Henri Bienvenue Sene, Seynabou Seck, Alfred Kouly Tine, Daniel Gomis, Tidiane Diop
KEYWORDS:
Saline Soils, Phosphogypsum, Rice Cultivation, Heavy Metals, Kobongoye
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.16 No.9,
September
21,
2026
ABSTRACT: The Kobongoye rice valley, located in the municipality of Fimela (Fatick region, west-central Senegal), faces a major challenge of soil salinization and/or acidification. To restore fertility to the valley’s rice paddies, an organo-mineral amendment composed of 0.4 t/ha of phosphogypsum and 0.5 t/ha of cow manure was applied. This before-and-after field study evaluates whether a combined phosphogypsum and cow-manure amendment improves saline rice soils while assessing Pb and Cd accumulation. Soil samples from 29 grid locations were analyzed for physicochemical properties and trace metals, with PCA and spatial interpolation used to examine variability. The soil samples were taken with an auger at a depth of 0 - 30 cm, based on systematic sampling in July 2023 before amendment and in May 2024 after amendment at the same location. The study reports lower EC, modest pH improvement in much of the site, and higher Pb and Cd concentrations that remain below the cited soil thresholds. Organic matter, nitrogen, phosphorus, and potassium contents did not change substantially but did exhibit spatial variation. In light of these results, the use of phosphogypsum appears to be a promising technology, but it requires particular attention to trace metal elements.