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 ph osphate (KRP) application (0, 310, 620, 1240 and 2480 ppm P, equivalen t to 0, 775, 1550, 3100 and 6200 kg P/ha) and vesicular-arbuscular myc orrhizal fungi (VAMF) Glomus manihotis Howeler, Sieverding & Schenck o r Glomus aggregatum Schenck & Smith emend. Koske was evaluated in an a lkaline sandy soil. The F. albida seedlings grew poorly without mycorr hizal colonization and without KRP applications. For non-VAM Faidherbi a, the maximum growth response and both P and N uptake in shoots was a chieved 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 nutr ient contents at any KRP application rate. Although mycorrhizal coloni zation was comparable at all levels of KRP application, the impact of nutrient content of the shoot varied. Finally, VAM plants did not accu mulate more biomass than non-VAM plants at 620 ppm P and above. Growth response and mycorrhizal dependency decreased as KRP applied levels i ncreased. These results suggest that VAM Faidherbia seedlings take up more P from soil and KRP than non-VAM.