Carbon, nitrogen and phosphorus mineralization potential of native agroforestry plant residues in soils of Senegal.

The objectives of this study were to investigate Piliostigma reticulatum (shrub) and Cordyla pinnata (tree) residues for chemical composition, and C, N, and P mineralizationin Senegalese soils. Soil samples (Sols ferrugineux tropicaux) were collected from a native agroforestry system beneath and outside a C. pinnata canopy. Soils were incubated for 11 weeks with P. reticulatum (leaves), C. pinnata (stem, leaves or stem + leaves), peanut (Arachis hypogea), or pearl millet (Pennisetum glaucum) residues. Nitrogen and P mineralization for the soil-plant mixtures was determined by periodic leaching with a 0.01 M CaCl 2 solution. An additional separate incubation was conducted to investigate C mineralization. The results showed that only peanut residues caused net N mineralization, while N immobilization occurred in the remaining treatments in both the soils derived from beneath or outside the canopy. This indicates that, at least in the short-term, these agroforestry residues would not likely be a source of N ...