Abstract

Comparative rhizosphere microbiological and physicochemical properties of Arachis Hypogeae (Groundnut) and Hibiscus Esculentus (Okro)

Author(s): O.A.Oyewole, I.N.Okoliegbe, E.E.Akwu

The rhizosphere microbiological and physicochemical properties of Hibiscus esculentus (okro) and Arachis hypogeae (groundnut) were examined for eight weeks. Samples from rhizosphere and non-rhizosphere soil (control) were collected and analyzed using standard microbiological and physicochemical methods. The mean total aerobic bacterial count (cfu/g) of rhizosphere and non-rhizosphere soil for weeks 4, 6 and 8 ranged from 8x109 - 2x1010 and 4x109 - 3x1010 in rhizosphere of okro and groundnut respectively while non-rhizosphere soil had count of 3x108 cfu/g. The mean total anaerobic bacteria count (cfu/g) of rhizosphere and non-rhizosphere soil for weeks 4, 6 and 8 ranged from 1x109-1x1010 and 4x108- 2x1010 in rhizosphere of okro and groundnut respectively while non-rhizosphere soil had a count of 2x108 cfu/g. The mean total fungal count (cfu/g) of rhizosphere and non-rhizosphere soil for weeks 4, 6 and 8 ranges from 1x107 and 2x107- 3x107 in rhizosphere of okro and groundnut respectively while the non-rhizosphere soil had a count 4x106 cfu/g and the mean total actinomycetes count (cfu/g) of rhizosphere and non-rhizosphere soil for weeks 4, 6 and 8 ranged from6x109 - 8x109 and 1x109 - 7x1010 in rhizosphere of okro and groundnut respectively while the non-rhizosphere soil a count of had 2x108 cfu/g. Microorganisms isolated from rhizosphere soils were species of Bacillus, Micrococcus, Streptococcus, Alternaria, Aspergillus, Mucor, Penicillium, Fusarium, Actinomyces, Streptomyces and Norcardia while the microorganisms isolated from the non-rhizosphere soil were species of Bacillus, Micrococcus, Aspergillus, Mucor and Actinomyces. The results of the physicochemical analysis revealed that there were significant differences (P<0.05) in the mean electrical conductivity, potassium, phosphorus, nitrogen, organic carbon (%), organic matter (%), moisture (%) and sulphur between weeks 4, 6 and 8 but there was no significant difference (P>0.05) in their mean pH and sodium. There was also a significant difference (P<0.05) between the microbiological and physicochemical properties of rhizosphere compared with non-rhizosphere soil. The result of this study revealed the presence of several microorganisms in the rhizosphere of okro and groundnut that can serve economic importance.