Rock phosphate and vesicular-arbuscular mycorrhiza effects on growth and nutrient uptake of Faidherbia albida (Del) seedlings in an alkaline sandy soil

Response of Faidherbia albida (Del.) to five levels of Kodjari rock phosphate (KRP) application (0, 310, 620, 1240 and 2480 ppm P, equivalent to 0, 775, 1550, 3100 and 6200 kg P/ha) and vesicular-arbuscular mycorrhizal fungi (VAMF) Glomus manihotis Howeler, Sieverding & Schenck or Glomus aggregatum Schenck & Smith emend. Koske was evaluated in an alkaline sandy soil. The F. albida seedlings grew poorly without mycorrhizal colonization and without KRP applications. For non-VAM Faidherbia, the maximum growth response and both P and N uptake in shoots was achieved with the 620 ppm P. However, even without KRP application, VAM plants achieved better results in terms of biomass. VAM plants with G. manihotis and G. aggregatum improved plant growth and increased nutrient contents at any KRP application rate. Although mycorrhizal colonization was comparable at all levels of KRP application, the impact of nutrient content of the shoot varied. Finally, VAM plants did not accumulate more biomass than non-VAM plants at 620 ppm P and above. Growth response and mycorrhizal dependency decreased as KRP applied levels increased. These results suggest that VAM Faidherbia seedlings take up more P from soil and KRP than non-VAM.