Microbial population dynamics along a toposequence in the southern Guinea savanna zone of Nigeria. International Journal of Agriculture and Rural Development. 17(1): 1603-1612

Abstract

A study was carried out at the Soil Science Laboratory of the School of Agriculture and Agricultural Technology, Federal University of Technology, Minna situated at Bosso in the month of June, 2009. The aim was to evaluate the population of bacteria, fungi and actinomycetes along a toposequence under four different land use positions (Teak, Gmelina, Cashew and Fallow) at three soil depths (0 - 5 cm, 5 -10 cm, 10 - 15 cm) representing a 4 x 3 factorial experiment in a complete randomized design (CRD). Soil samples were collected with auger and sterilized after each collection. Soil samples from the same position and depth were bulked, mixed and labeled. One part was air dried for physico-chemical properties while the other part was refrigerated for microbial counts using the plate count methods. Results revealed that the interactive effect of land use and depth significantly affected microbial counts (cfu x 10n/g soil) at P = 0.05. Bacterial count (cfu x 108/g soil) and fungi count (cfu 104/g soil) decreased with depth in all the land uses. Fallow soils recorded the highest bacterial count, followed by Teak, Cashew and Gmelina in that sequence. Similarly, Fallow soils recorded the highest fungi count, followed by Teak, Gmelina and Cashew in that order. The trend observed for actinomycetes count (cfu x 107 / g soil) was same as those for bacteria and fungi counts, except that Gmelina soil was higher in actinomycetes count than Cashew soil. Present study clearly shows that land uses have significant effect on microbial population. Further studies should be carried out to include other forms of land uses in order to detect detrimental ecosystem changes and possibly prevent further degradation.