Effects of rockphosphate and arbuscular mycorrhizal fungi on growth and nutrition of Sesbania sesban and Gliricidia sepium

A greenhouse experiment was conducted to evaluate the effects of different indigenous arbuscular mycorrhizal (AM) fungi on the mobilization of phosphorus from Senegalese natural rock phosphate (NRP) for growth of Gliricidia sepium and Sesbania sesban seedlings. Levels of tested NRP were compatible with high AM fungal proliferation but modified pattern of root colonization according to plant cultivar and fungal species. NRP applications and AM inoculation positively stimulated growth parameters and shoot mineral mass of G. sepium and S. sesban after four months cultivation. More than 200% of weight gains in S. sesban were recorded with all AM fungi combined with 600 or 800 mg NRP. With Gliricidia, only Glomus aggregatum in presence with these high NRP levels  induced the same tendency. Glomus fasciculatum enhanced twice height growth of Sesbania in presence of 400, 600 and 800 mg NRP. The impact of dual application of AM fungi and NRP on nutritional content was more marked with Sesbania than in Gliricidia seedlings.   Key words: Rock Phosphate, AM fungi, Ghricidia sepium, Sesbania sesban.