The lack of available phosphorus in Burkina Faso’s tropical ferruginous soils led us to produce an organic fertiliser called «Neyma compost» using local materials. The Fischer block system of 4 treatments with 3 replicates was implemented during the 2023 growing season at the Kamboinsé Centre for Environmental, Agricultural and Training Research to evaluate the performance of compost on the availability of assimilable phosphorus in cowpea crops. The treatments were the control (T0); 2 t/ha of Neyma compost incorporated during ploughing (T1); 2 t/ha of Neyma compost applied to the seed holes 15 days after sowing (T2) and 1 t/ha of Neyma compost incorporated during ploughing followed by 1 t/ha applied to the seed holes 15 days after sowing (T3). The objectives of the study were to evaluate the rate of available phosphorus in soils according to application methods, determine the most efficient application method in terms of available phosphorus content, and determine the soil properties that control phosphorus availability. The results showed that the assimilable phosphorus content was improved by approximately 21% overall through the application of Neyma compost, with the assimilable phosphorus content varying from 3.5 ppm to 6.1 ppm under the different compost application methodsThe greatest improvement in assimilable phosphorus content (56%) was achieved with the T1 application method. The availability of phosphorus varied according to the physical and chemical parameters of the soil. The methods of application and doses of Neyma compost were the main factors influencing the availability of phosphorus in the soil. Neyma compost may be a promising alternative for sustainable soil management in Burkina Faso by small-scale producers.