Advances in knowledge of processes in soil–tree–crop interactions in parkland systems in the West African Sahel: A review By Jules Bayala, Josias Sanou, Z. Teklehaimanot, Sibiri J. Ouédraogo, Kalinganire Antoine, Ric Coe, Meine Van Noordwijk Tagged with: Ecosystem services, Management, Modeling, Productivity, Sub-Saharan Africa, Sustainability