Phosphogypsum and Organic Matter: Sustainable Solution for the Rehabilitation of Saline Lands in the Saloum Delta, Senegal

Constituting the northern margin of all the “rivers of the South” which extend continuously on the Atlantic coast of West Africa, the Saloum Delta is full of important economic, cultural and ecotourist potentialities. Despite its importance, the area faces a variety of threats from a combination of natural and anthropogenic factors. The most important being the worrying phenomenon of salinization of agricultural land, which is seriously affecting the livelihoods of communities in the area. Faced with this situation, a technique for recovering salted rice land based on the use of phosphogypsum and organic matter such as cow dung and/or groundnut shell and poultry manure was tested at the level of abandoned production lands. This is composed of different stages such as the identification and characterization of the soils of the sites, the input supply, the ploughing and the monitoring of the evolution of the physico-chemical and agronomic parameters. The analysis of the results of the monitoring shows a high degree of effectiveness of the system for the recovery of rice-growing lands. Indeed, the electrical conductivity which is the main physico-chemical parameter followed has seen a very positive evolution. The seeded soils have been upgraded from class III to V of saline soils, to extremely saline, with electrical conductivity greater than 2000 μS/cm before the installation of the device in class I of unsaline soils with values well below 500 μS/cm. This decrease in salinity has generated very interesting yields, the average of which is estimated at 6.17 t/ha paddy rice for the variety Sahel 108. This, in relation to the 58 ha planted in the intervention area leads us to estimate the total production at 357.58 t. Given these spectacular results of the scheme on salt land abandoned for several decades, the need to develop a strategy for popularizing technology and building the capacity of actors in order to recover abandoned rice fields.