O. Fagbola et al., CONTRIBUTION OF ARBUSCULAR MYCORRHIZAL (AM) FUNGI AND HEDGEROW TREES TO THE YIELD AND NUTRIENT-UPTAKE OF CASSAVA IN AN ALLEY-CROPPING SYSTEM, Journal of Agricultural Science, 131, 1998, pp. 79-85
A field trial on alley-cropping was conducted at the University of Iba
dan research farm in the 1990/91 cropping season to assess the contrib
utions of arbuscular mycorrhizal (AM) fungi and hedgerow woody legumes
to the yield and nutrient uptake of cassava (Manihot esculenta Crantz
) as an intercrop in an infertile soil. The trial also investigated th
e influence of AM fungi on the interplanting of a nonnodulating woody
legume Senna siamea (syn. Cassia siamea) with a nodulating woody legum
e (Leucaena leucocephala). AM contributions to cassava were greater th
an the hedgerow contributions, which demonstrated that AM associations
are an essential component in the nutrition of cassava. In contrast t
o cassava, AM inoculation only influenced the leaf dry weight and upta
ke of nutrients of non-interplanted woody legumes but not the above-gr
ound biomass and P uptake of interplanted woody legumes. However, non-
inoculated interplanted Leucaena benefited more from indigenous AM fun
gi than the competing Senna. The negative contributions to the nutrien
t uptake (K, Ca and ME) of cassava by hedgerows and the lack of respon
se to AM inoculation in interplanted hedgerow woody legumes could be a
ttributed to root competition among the different plant species growin
g in close proximity to each other. The present results show that cass
ava benefits more from AM association than Leucaena which in turn bene
fits more than Senna in an alley-cropping system.