In dry areas, salinisation is one of the main causes of soil degradation. To limit this impact on crops, organic amendments can be used. ISFERALDA project proposes to use residues of date palm (Phoenix dactylifera L.) cultivation, one of the main crops in the arid agro-ecosystems of North Africa, to prevent soil degradation and improve soil fertility. This study focuses on the properties of biochar produced by pyrolysis of palm date residues. Traditional production methods don’t allow precise control of the oxygen level during pyrolysis, although this content can influence the properties of the biochar produced. The oxygen level can however be controlled by laboratory technics. Experiments have been performed with biochar produced at different oxygen levels (0%: BC0, 3%: BC3 and 7%: BC7) to assess the ability of the biochar to retain the sodium present in the soil solution and limit soil salinisation. The three biochars were rinsed with ultrapure water before adsorption experiments resulting in a significant release of K, Ca, Mg and Na into solution, which could increase soil salinity in the field. The adsorption experiments performed on rinsed biochars at five different concentrations of Na (between 50 mg.L-1 and 1600 mg.L-1) evidenced low quantities of Na adsorbed regardless of the biochar considered with the lowest proportions retained for BC0 (around 11%). Following adsorption experiments, desorption was studied with ultrapure water. For the highest quantity adsorbed (around 8000 mgNa.kg-1) the proportion desorbed represents between 30 and 40% of the quantity adsorbed for the three biochars. This study showed that biochar produced from date palm residues had a relatively low Na retention capacity and that the presence of oxygen, which is difficult to control in traditional systems, had very little impact on the composition and reactivity of the biochar.