Growth and Phosphorus Uptake Responses of Bambara Groundnut (Vigna subterranea (L.) Verde) to Inoculation with Arbuscular Mycorrhizal Fungi in two Acid Soils

Abstract

The effect of arbuscular mycorrhiza on growth and nutrient uptake by bambara groundnut (Vigna subterranea) grown in two acid soils (Basachia series, a Haplustox and Udu series, a Gleyic Luvisol) was investigated in a phytotron. The aim was to determine the extent of infection in the roots of V. subterranea plants by indigenous arbuscular mycorrhizal fungi, and its effect on the uptake of phosphorus and dry matter production. The soils were analyzed to determine exchangeable cations, exchangeable aluminium ammonium, and nitrate nitrogen and available phosphorus. Arbuscular mycorrhizal fungal inoculum was produced from pot cultures of  mycorrhizal fungi indigenous to the soils using highly mycorrhizal onion plants in non-sterile samples of the soils. Bambara groundnut was planted in the soils with and without the application of inoculum. Inoculation of soils with arbuscular mycorrhizal fungi significantly enhanced the uptake of phosphorus in both soils. Dry matter production in mycorrhizal plants was significantly greater than non-mycorrhizal plants. The dependency of V. subterranea on the mycorrhizal condition for improved growth evaluated in Basachia series and Udu series soils, were 16.95% and 20% respectively. It is suggested that the arbuscular mycorrhizal association in bambara groundnut could be harnessed to improve the uptake of nutrients such as phosphorus in soils with marginal fertility to increase yields.

Keywords: Arbuscular mycorrhizal fungi, Vigna subterranea, mycorrhizal dependency, phosphorus uptake.