Soil samples were collected before planting vetiver grass to
determine chemical properties. Samples were taken at three points
in each experimental plot and mixed to form a representative soil
sample for each site.
Soil samples adjacent to vetiver roots were collected using a soil
auger from each plot in August (rainy season) 1 year after planting.
Two layers, one the upper level (0–30 cm) and the other the lower
level (30–60 cm), of the soil profile of the vetiver-planted and the
control plots (with no vetiver grass), were sampled separately for
analysis of biological and chemical properties.
Microbial populations of the rhizosphere soil samples were estimated using the dilution plate count method in enrichment and
selective media.
Analyses of cellulose decomposing microbes, that is, cellulolytic
bacteria (BC), cellulolytic fungi (FC) and cellulolytic actinomycetes
(AC) were made using the method ofMurao et al. (1979).
Azotobacterwere counted in a selective media, Azotobacter agar
modified I (Ronald, 1995)