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Phosphorus (P) is an essential constituent for all living organisms, scarce with finite reserves. P is deficient in Sub Saharan Africa threatening primary production. That in part is due to the occlusion of Pin Fe and Al oxides in the weathered soils. This problem is aggravated by the high cost of P fertilizers, lack of both appropriate technologies for its application and government support to facilitate and strengthen its use in small-scale farming. Evaluation of soil P availability in the mixed-species plantations established on natural savannas in the Congolese coastal plains highlights that high C accretion involves low P availability in the mixed-species (50% acacia and 50% euca-lyptus) stands relative to others. P availability in 0-0.05 m in the mixed-species stands (6.94 +/- 0.45 mg kg(-1)) was lower than in acacia (8.07 +/- 0.63 mg kg(-1)) and eucalyptus (8.46 +/- 0.79 mg kg(-1)). C stock in the 0.25 m was higher in the mixed-species (17.8 +/- 0.7 t.ha(-1)) relative to acacia (16.7 t.ha(-1) +/- 0.4) and eucalyptus (15.9 t.ha(-1) +/- 0.4). However, afforesting the inherently nutrient-poor and sandy soils beneath savannas evidenced an improvement in soil P availability to plant, along with soil N status and C sequestration in both soil and biomass, with a potential impact on mitigating climate change. (C) 2019 Elsevier B.V. All rights reserved.