




































In ternationa l
Scholars
Journa ls

 

African Journal of Agricultural Marketing ISSN 2375-1061 Vol. 8 (9), pp. 001-008, September, 2020. Available online 
at www.internationalscholarsjournals.org © International Scholars Journals 

 

Author(s) retain the copyright of this article. 
 
 

 

Full Length Research Paper 

 

Effects of slash and burning on soil microbial 

diversity and abundance in the tropical rainforest 

ecosystem, Ondo State, Nigeria 

 
Adeduntan Sunday Adeniyi 

 
Department of Forestry and Wood Technology, Federal University of Technology, P. M. B. 704, Akure, Nigeria. 

E-mail: niyi_gbenga@yahoo.co.uk. Tel: 08063480727. 
 

Accepted 20 July, 2020 
 
This study was carried out to examine the effects of slash and burn on the diversity and abundance of soil 
microorganisms. Composite soil samples were collected from the study area before burning and two weeks after 
burning progressively for a period of three (3) months. The bacteria and fungi in the soil samples were isolated and 
identified. In addition, the pH, soil temperature and soil moisture content of the samples were determined. The results 
show that the diversity and abundance of the soil microorganisms decreased significantly (p 0.05) within the fourteen 
and twenty-eight days after burning. However, a significant increase in the abundance and diversity of the 
microorganism was recorded as from the forty-two days after burning. The soil pH was also observed to increase 
significantly between the fourteen and twenty eight days after burning. The results further revealed that there was 
significant (p 0.05) increase in bacteria and fungi abundance after burning. The relationship between soil pH and 
bacteria was significant, while there was no significant relationship between soil pH and fungi. The relationship 
between temperature, fungi and bacteria were not significant (R

2
 50%). Total microorganism abundance and diversity 

significantly increased following burning during the current study. 
 
Key words: Bacteria, fungi, mineralization, yield, species, soil. 

 
INTRODUCTION 

 
Slash and burn used to be a viable ecological strategy to 
sustain agriculture in the tropics. Farmers maintained 
different plots, resulting in a mosaic of plots under 
cropping and fallow, allowing natural processes of soil 
regeneration (Brandy and Weil, 1990; Altieri, 2002), but 
human activities of none sustainable agricultural practices 
disrupt this equilibrium.  

Slash and burn has long been considered to be the 
most adapted farming system in the humid forest zone 
(Brandy and Weil, 1990), especially in areas of low popu-
lation density. There is a nutrient flux during slash and 
burn; ash from burned biomass is incorporated into the 
soil resulting in an increase in soil fertility. Carbon and 
Nitrogen are largely volatilized but Phosphorus and 
cations are transferred from the biomass to ash and then 
into the soil. During subsequent rains, cations may be 
leached, but generally, soils are enriched by ash after 
rainfall (Nye and Greenland, 1990, Giardima et al., 2000). 
Farmers grow crops for a few years, until soil fertility, 

 
 
 

 
weed infestation and disease reduce crop yield below an 
acceptable level (Akobundu, 1987). 

In slash and burn farming system, the soil can only fully 
recover, if left undisturbed for many years during long 
fallow or in improved fallow system (Ahn, 1979). Fallows 
in this way help to re-establish the equilibrium that 
prevailed initially in the soil before the clearing of the 
forest. Unfortunately, some major external driving forces 
have led farmers to reduce the fallow period. Increasing 
population density in forest regions and the subsequent 
increasing demand for food, fibre and shelter, forced 
farmers to shorten follow length, hence jeopardizing the 
sustainability of this farming system (Eyasu and Scones, 
1998). The practice of slash and burn has been reported 
to negatively affect soil quality, thereby compromising the 
resilience of the system (Lai, 1997).  

It is important to understand the impact of slash and 

burn on soil microorganism, as they are crucial to the 

stability, regulation and functioning of all forest 

file:///C:\Users\user\Documents\REPUBLICATION\AGRICULTURAL%20SCIENCES\AppData\Local\Temp\www.internationalscholarsjournals.org


 
 
 

 

ecosystems (Reichle, 1997). Future use of fire in 
management of forest should be based on a sound 
knowledge of its potential impact upon components of the 
community. The examination of species changes 
following slash and burn is particularly, important for 
understanding the extent and duration of community 
alterations. Studies involving higher taxonomic level can 
however, provide clear indication that it is sensitive or 
robust taxa for inclusion in future studies. Long-term 
studies of the soil microorganism’s species composition 
of communities and their response to fire are urgently 
required. 

Soil quality and resilience have a profound impact on 
productivity and environmental quality. Soil quality refers 
to the soil capacity to produce economic goods and 
services and to regulate the environment (Lai, 1997), and 
its capacity sustain plant and animal productivity, 
maintain or enhance water quality and promote plant and 
animal heath. Soil quality is thus an ideal indicator of sus-
tainable land management (Lai, 1997). Soil resilience is 
the ability of the soil to restore its life support processes 
and environmental regulatory function after major 
anthropogenic perturbation, that is, its ability to absorb 
Agriculture practices are among the largest source of 
stress and disturbance of the environment. Soil biological 
processes contribute to soil fertility enhancement by 
increasing the amount and efficiency of nutrient acqui-
sition and recycling, the regulation of the retention and 
flow of water and nutrients, and the maintenance of good 
soil physical structure. Soil biological processes influence 
ecosystem functioning through nutrient cycling, organic 
mater transformation, microbial decomposition and 
nutrient retention.  

Through their feeding and nesting activities, soil 
organism generates and maintains soil chemical, physical 
and biological characteristic within the ecosystem. 
Bacteria can directly or indirectly modify soil properties 
through their feeding activities, burrowing and casting 
(Ahn, 1979).  

Burning removes the vegetation and may release a 
pulse of nutrient to fertilize the soil. Ash also increases 
the pH of the soil, a process that makes certain nutrients, 
(especially phosphorous) more available in the short 
term. Burning also drives off, temporarily, soil micro-
organism, pests and established plants along enough for 
crops to be planted in the ashes. Before artificial fertile-
zers were available, fire was one of the most widespread 
methods of fertilization. The aim of this study is therefore, 
to find the effects of slash and burn on soil microbial 
diversity and abundance in the tropical rainforest 
ecosystem in Ondo state, Nigeria. 
 

 
MATERIALS AND METHODS 
 
The study area 
 
This study was carried out at Obanla natural forest, which is a 

 
 
 
 

 
portion of the forest left behind during land clearing for the 
establishment of the Federal University of Technology, Akure 
(FUTA) Ondo State, Nigeria. The forest was formerly part of Akure 
Forest Reserve. It is located on Longitude 050 18E and Latitude 
070 17 N, along Akure-Ilesha Road. The forest is about 9.34 ha in 
size, translating into 1.5% of total land mass. Generally, the 
vegetation zone is the tropical humid lowland forest ecosystem. The 
ecological zone has been described in details by Nwoboshi (1982), 
Okojie (1996) and Adekunle (2002).  

The soil of the area is well drained and classified as ferruginous 
soil on crystalline rocks of basement complex. The soil is also 
classified in terms of soil texture as sandy clay loam. The pH varies 
between 6.7 and 7.2 indicating a neutral soil reaction. The mean 
monthly temperature is about 28°C. The precipitation is heavy and it 
varies between 1500 and 2500 mm per annum. The mean monthly 
relative humidity is about 74%. The fairly moderated daily 
temperature is as a result of cloudiness and heavy precipitation. 
 
 
Method of soil collection 
 
In the forest habitat, one hectare (100 × 100 m) land area was 
centrally established. This was further divided into 25 sample plots 
of 20 × 20 m where five plots were randomly selected (12.5% 
sampling intensity). In each of the selected plots, soil samples were 
collected at a depth of 0 - 10 cm from five points before and two 
weeks after burning. The soil samples were taken to the laboratory, 
where isolation of microorganisms was carried out. 

 

Bacteria isolation, identification and counting 
 
The standard procedures for determining the total number of soil 
microbes were adopted for bacteria and fungi (Alexander, 1997). 
Suspension of the soil samples was prepared with sterile water and 
a serial dilution of five factors was made for accurate counting. 
Then 1 ml of the appropriate dilution was carefully transferred to 
sterilized petri dishes containing sterile molten nutrient agar at 
about 37°C. This was mixed and allowed to solidify. It was then 
incubated for 24 h. The bacteria that grew into colonies were sub-
cultured to obtain pure culture for easy identification. Identification 
was done according to Bergey’s manual of determinative 
bacteriology. 

Fungi culturing involved serial dilution of the suspension using 
molten malt extract agar. This was kept in an incubator at 30°C for 
5 days. Fungi that grew were sub-cultured to obtain pure culture for 
easy identification and they were identified with the criteria of 
Rhode and Hartman (1980). 

 

Soil pH determination 
 
The soil pH was determined with the aid of glass electrode pH 

meter in the soil solution of 0.01 mol L
-1

 calcium chloride. 

 
Soil moisture content determination 
 
The oven dry method was used to determine the moisture content 
of the soil samples. 100 g was weighed and placed in an oven 
maintained at 105 ± 2°C for a period of 24 h. Thereafter, the soil 
samples were removed from the oven, and allowed to cool in a 
desiccators containing silica gel and then reweighed. The samples 
were returned into the oven to dry for another 30 min and allowed to 
cool again in the desiccators. Oven drying and cooling were 
repeated until constant weight was obtained. The moisture content 
was then calculated using the formula: 



 
 
 

 
MC= (Mn - Mo) ⁄ Mn × 100 
 
Where: MC = Moisture Content, Mn = Weight of soil with moisture 

(wet weight), Mo = Weight of soil without moisture (oven dry weight) 

 

Methods of data analysis 
 
The data on bacteria and fungi count obtained were subjected to 
repeated analysis of variance (ANOVA) . Regression was done to 
find out the type of relationship between soil pH, bacteria and fungi 
count; between soil moisture content, bacteria and fungi count and 
the one existing between soil temperature, bacteria and fungi in the 
study area. SPSS statistical package was employed to analyze the 
data 

 

RESULTS 

 

Effects of slash and burn on bacteria diversity and 

abundance in the study area 
 
The diversity of bacterial obtained in the study is 
presented in Table 1. The results revealed that Bacillus 
cereus, Proteus vulgaris, Clostidium sporogenes, 
Aeromana hydrophylla and Vibro anguillarum, were 
encountered in both the burn and un-burnt plots which 
implies that they are resistance to burning.  

The species and the relative abundance of bacteria 
obtained in this study are presented in the Table 2. The 
counts are expressed as Colony Forming Unit per gram 

(cfu/g) with factor of 10
6
. This shows that burning dras-

tically reduced the abundance of bacteria. However, the 
abundance of bacteria increases from fifty-six days after 
burning until it reaches eighty-four days after burning. (It 

increases from 1.48 x 10
6
 to 3.02 x 10

6
 in plot 1, from 

1.21 x 10
6
 to 2.78 x 10

6
 in plot 2, from 2.17 x 10

6
 to 2.48 

x 10
6
 in plot 3 and 2.64 x 10

6 to
 2.74 x 10

6
 in plot 4).  

Table 3 shows that burning has devastating effect on 
diversity of fungi. Only species that were resistant to fire 
survived the fire incidence, these species include; 
Rhizopus stolonifer, Candida albidum and Trichoderma 
uridea. However, the diversity began to increase from 6 
weeks after burning. It was observed that at 42 days after 
burning, species that were not present before burning 
were introduced, which makes the number (diversity) of 
fungi species to be more than what was obtained before 
burning.  

Mean fungi abundance obtained in the study area is 
presented in the Table 4. The ANOVA for the bacterial 
count shows that there were significant differences in the 
bacterial count in the study area due to burning (Table 5). 
The mean separation shows that abundance of bacterial 
was significantly higher (p 0.05) at 12th weeks after 
burning, followed by 10th and 8th weeks after burning 
respectively (Table 6). 

 

Soil pH analysis 

 

It was observed that the pH of the soil samples 

 
 
 
 

 

significantly increased 2 weeks after burning (Tables 7 
and 8) and this could be as a result of the ash added to 
the soil from burnt biomass. The soil pH was high at 4th 
(5.16) and 6th weeks after burning (5.15). But there were 
reductions from the 8th week after burning.  

The ANOVA Table (Table 9) shows that there was 
significant difference in the fungi count in the study area 
due to burning. The result of the mean separation shows 
that the abundance of Fungi was significantly (p 0.045) 
higher at 8th weeks after burning, followed by 6th and 
12th weeks after burning (Table 10). 

A summary of the results of the regression analysis 
between soil pH and bacterial is presented in Table 11. 
The correlation co-efficient shows that the value of R is 
positive in the study area, suggesting that there was 
significant correlation between soil pH and the number of 
bacterial. This implies that, an increase in the pH 
increases the diversity and abundance of bacteria in the 
study area. Also, the regression analysis between soil pH 
and fungi shows a positive and significant correlation. 
However, the regression analysis between soil tempe-
rature and fungi in the study area shows that the value of 

R
2
 is positive, suggesting that there is significant corre-

lation between the soil temperature and fungi. Likewise, 
the regression analysis between soil temperature and 
bacteria shows that the value of R is also positive, 
suggesting that there is significant correlation between 
the soil temperature and bacteria abundance.  

The implication of this observation is that most species 
of soil microbes are poorly adapted to survive the period 
of high temperature. But the regression analysis between 
soil moisture content, bacteria and fungi in the study 
habitat, shows a negative relationship, suggesting that 
there was no significant correlation between the soil 
moisture content and the soil microbes in the study area. 
The implication of this is that as the soil temperature 
increases, the soil moisture content reduces, and this 
tends to affect the physical, biological and the chemical 
processes in the soil. 
 

 

DISCUSSION 
 

The results show that the abundance of soil micro-
organism significantly increased in the study area forty-
two days after burning (Tables 1 and 2). This suggests 
that many soil organisms survived during burning by 
moving down the soil profile. These are the true soil 
organisms with suitable morphological attributes, such as 
size and shape, for fast movement through inter-ped 
spaces.  

Burning has great effect on diversity of bacteria. Only 
species that are resistance to burning survived the effects 
of burning, these species include Bacillus cereus, Proteus 
vulgaris and Clostridium sporogenes. The diver-sity 
increases as from the 6th week after burning. It was also 
observed that the 8th, 10th and 12th weeks after burning 
witnessed an increase in bacteria diversity. This 



 
 
 

 
Table 1. Bacteria diversity in the study area.  

 
   

Before 
14 days 28 days 42 days 56 days 70 days 84 days 

 

 S/N Name after after after after after after  

 
burning  

   burning burning burning burning burning burning  

    
 

 1 Actinomyces spp + - + + - + + 
 

 2 B. cereus + + + + + + + 
 

 3 Streptococcus feacalis + - - - - + + 
 

 4 Escherichia coli + + + - - - - 
 

 5 P. vulgaris + + + + + + + 
 

 6 Micrococcus leutus + - + - - - - 
 

 7 Salmonella spp. + - - - - - - 
 

 8 C. sporogenes + + - + + + + 
 

 9 Micrococcus lactis + - - - + + + 
 

 10 Pseudomonas aeniginosa - - + + - + + 
 

 11 Klebsiella scleromalacia + - - + + + + 
 

 12 Aeromonas hydrophyila + + - + + + + 
 

 13 V. anguillarum + + + - + + + 
 

 14 Shigella dysentenae + - - - + + - 
 

 15 Bacillus subtilis - + - - + - + 
 

 16 Aerococcus viridians + + + + + - - 
 

 17 Streptococcu lactis + - - + + + + 
 

 18 Branbamella catlarhelis - - - + - - - 
 

 19 Rhizobium japomicum - - - - + - + 
 

 20 Bacillus megaterium - - - - + - + 
 

 21 Azotobacter spp. - - - - + - + 
 

 22 Erwinia herbicola - - - - + + + 
 

 23 Alcaligenes feacalis - - - - + + + 
 

 24 Erwinia amylovora - - - - - + + 
 

 25 Streptomyces spp. - - - + - + + 
 

  Total 15 8 8 11 16 16 17 
  

Key: + = Present; – =Absent. 
 
 

 
Table 2. Bacteria abundance (CFU/g) in the study area.  

 
 S/N Soil sample Mean of burnt plot over time Unburnt plot over time 

 1 Before burning 1.88 × 10
6
 2.34 × 10

6
 

 2 14 days after burning 1.37 × 10
6
 2.42 × 10

6
 

 3 28 days after burning 1.45 × 10
6
 1.96 × 10

6
 

 4 42 days after burning 1.75 × 10
6
 1.44 × 10

6
 

 5 56 days after burning 1.93 × 10
6
 2.75 × 10

6
 

 6 70 days after burning 1.93 × 10
6
 2.68 × 10

6
 

 7 84 days after burning 2.76 × 10
6
 3.11 × 10

6
 

 
 

 

could be as a result of an increase in the soil pH after 
burning, which reflected changes in chemical properties 
of the soil such as the cation exchange capacity, which 
now favour some species of microorganisms that were in 
the habitat before burning. The chemical composition of 
soil often determined the abundance and distribution of 
microorganism. Similar observation was made by 

 
 

 

Seasted (1980), who reported that, burning, causes the 
mineralization of litter and vegetation, with an increase in 
a number of nutrients including nitrogen, phosphate, 
potassium, calcium, sodium and magnesium. Fungi diver-

sity increased greatly in the 56
th

, 70
th

 and 84
th

 days after 
burning.  

The regression analysis shows that the effect of soil pH 



 
 
 

 
Table 3. Fungi diversity in the study area.  

 
   

Before 
14 days 28 days 42 days 56 days 70 days 84 day 

 

 S/N Name after after after after after after  

 
burning  

   burning burning burning burning burning burning  

    
 

 1 Actinomyces sp. - + - + + - + 
 

 2 Aspergillus flavus + - - + - + - 
 

 3 Aspergillus fumigatus - - - + + + + 
 

 4 Aspergillus niger + - - + + + + 
 

 5 A. rapens - - - + + - - 
 

 6 Aureobasidim pathulana - - - + + - + 
 

 7 Botrytis cinrrea -  - + + + + 
 

 8 Candida albidum + + - + + + + 
 

 9 Chrysospium sp. - - - + + + + 
 

 10 Gonatobotrys simplex + - - + + + + 
 

 11 Mucur mucedo + - - + + + - 
 

 12 Mycotypha sp. - - - - + - - 
 

 13 Neurospora crazza - - - + + + + 
 

 14 Peniciluma italicum + - - + - + - 
 

 15 Rhizopus nigricans + - - + + + + 
 

 16 R. stolonifer + + - + + + + 
 

 17 Starchybotrys sp. - - - - + - + 
 

 18 Trichoderm uridea + + + + + + + 
 

 19 Umbelopsis sp. - - - - + - - 
 

 20 Varicospium elodeae - - - + + + + 
 

 21 Wardomyces anomalis + - - - + + + 
 

  Total 10 4 1 16 18 15 16 
 

 
Key: += Present, - = Absent. 

 

 
Table 4. Fungi abundance in the study area.  

 
 S/N Soil sample Mean burnt plot over time Unburnt plot over time 

 1 Before burning 0.41 × 10
4
 1.21 × 10

4
 

 2 14 days after burning 2.45 × 10
4
 0.91 × 10

4
 

 3 28 days after burning 0.01 × 10
4
 0.04 × 10

4
 

 4 42 days after burning 0.11 × 10
4
 0.25 × 10

4
 

 5 56 days after burning 0.08 × 10
4
 1.11 × 10

4
 

 6 70 days after burning 0.13 × 10
4
 0.07 × 10

4
 

 7 84 days after burning 0.14 × 10
4
 1.24 × 10

4
 

 
 
 

Table 5. ANOVA table showing the influence of burning on bacterial count.  
 

Source of variation SS DF MS F F-Calculated 

Days after burning and un-burn treatment 0.346348 6 0.024096 * 2.44 2.39 

Within group 0.67468 28    

Total 1.021029 34    
 

* = Denotes significant (p > 0.05). 
 

 

on bacteria abundance and diversity gave a positive 

correlation in the study area, which implies that there is 

significant positive interaction between the soil pH and 

 
 

 

bacteria counts in the plots. This means that the higher 

the soil pH, the higher the species of bacteria present and 

vice-versa. The fungi diversity shows that T. Uridea, 



 
 
 

 
Table 6. Mean separation of influence of burning on bacterial count.  

 
 Sources of variation Mean 

 2nd week after burning 6.11
b
 

 Before burning 6.26
a
 

 4th weeks after burning 6.15
b
 

 6th weeks after burning 6.23
ab

 

 8th  weeks after burning 6.28
a
 

 10th weeks after burning 6.30
a
 

 12th weeks after burning 6.39
a
 

 
*Figures with the same alphabet are not significantly different from each 

other. 
 
 

 
Table 7. ANOVA table showing the influence of burning on soil pH.  

 
 Source of variation SS DF MS F F-calculated 

 Days after burning and un-burn treatment 3.42970 6 0.571618 *6.72 2.44 

 Within group 2.37952 28 0.084983   

 Total 5.809229 34    
 

* = Denotes significant (p > 0.05). 
 
 

 
Table 8. Mean separation of influence of burning on soil pH.  

 
Sources of variation Mean 

Before burning 5.00
d
 

14 days after burning 5.73 
a
 

28 days after burning 5.16 
b
 

42 days after burning 5.15
c
 

56 days after burning 5.14
bc

 

70 days after burning 5.14
bc

 

84 days after burning 4.50
f
 

 
*Figures with the same alphabets are not significantly different from each other. 

 
 

 
Table 9. ANOVA table showing the influence of burning on fungi count.  

 
Source of variation SS DF MS F SIG 

Days after burning and un-burn treatment 2.480573 6 0.413429 *2.52 F-calculated 

Within group 4.250107 28 0.184787   

Total 6.73068 34    
 

*Denotes significant (p> 0.05) 
 
 

 

R. stolonizer and C. albidum were present before and 
after burning.  

The regression analysis shows that there is no signi-
ficant correlation between the soil pH and fungi count in 
the study habitat, as negative correlation was recorded. 
This is also supported by the works of Smith et al. (1994), 
who reported that soil fungi have a broader pH tolerance, 

 
 
 

 

but they might multiply at lower pH values. Also, the 
regression analysis between the soil temperature and the 
microorganisms shows that there was strong correlation 
between the soil temperature and the microbes. The 
implication of this is that most species of microbes are 
poorly adapted to survive the period of high temperature, 
particularly in moist forest environment, but could only 



 
 
 

 
Table 10. Mean separation of influences of burning on the fungi count.  

 
Sources of variation Mean 

Before burning 2.96 × 10
4de

 

14 days after burning 2.90 × 10
4e

 

28 days after burning 2.30 × 10
4f

 

42 days after burning 3.18 × 10
4b

  
   56 days after burning 3.23 × 10

4a
    

   70 days after burning 2.98 × 10
4d

    

   84 days after burning 3.05 × 10
4c

    

   *Variation in Alphabet shows significant differences.    

 Table 11. Summary of regression analysis.     
       

 S\N Regression type Regression equation R R2 Not significant 

 1 Between soil pH and bacteria -0.3866X + 7.591 0.4134 0.7719 0.488 

 2 Between soil pH and fungi -0.0234X + 5.3318 0.0731 0.0053 0.907 

 3 Between soil temperature and bacteria 0.3395X + 31.695 0.0686 0.631 0.913 

 4 Between soil temperature and fungi -5.07342X + 64.833 0.3490 0.533 0.565 

 5 Between soil moisture content and bacteria -12.1163X + 113.3511 0.8435 0.2115 0.073 
 6 Between soil moisture content and Fungi -3 .3714X + 45.5143 0.6904 0.4767 0.197 
 
NS= Not significant. 
 
 

 

survive within narrow ranges of climatic or microclimatic 
variation. According to Alexander (1997), microbial 
processes are influenced markedly by soil temperature 
change. Temperature also greatly affects physical, biolo-
gical and chemical processes in the soil. The regression 
analysis between soil moisture content and the micro-
organisms shows that there is negative correlation. This 
is supported by the works of Whelan et al. (1980), who 
reported that low moisture content levels and high 
temperature decreases the prevalence of dormant forms 
of microorganisms. Survival of some microorganisms 
subsequent to burning could be due to a variety of biotic 
and edaphic factors. Important biotic components include 
food source (plant or prey), competition, predation 
(including parasites) and the relationship with other 
species. Edaphic factors that are important to soil 
organisms include weather (precipitation, insolation, 
temperature and wind), microclimate (soil temperature, 
humidity), chemical (nutrients) and physical soil proper-
ties (soil texture and structure). Post burning activation of 
dormant microorganisms and hatching of eggs may 
significantly contribute to increase in microorganism’s 
abundance after burning. Many microorganisms survive 
unfavourable conditions by entering a dormant or 
resistant state (diapause or aestivation) in which develop-
ment is arrested, as reported by Huhta (2001). He further 
noted that the activation of these states is controlled by 
external stimuli such as temperature, humidity, and/or 
photoperiod which bring about an alteration in hormonal 

 
 
 

 

levels of the organisms. 
Increased abundance of some species of micro-

organisms after burning in this study may also have been 
affected by the periodic litter fall in the natural forest. 
Litter fall is characterized by periodic increase coinciding 
with bark fall. Plant re-growth and accumulation of litter 
after burning represents an increase in resources with 
time after burning, and may differ from the pre- burning 
resources in terms of quality and quantity. Atlas (1984), 
reported that the speed of reinvasion by soil 
microorganisms after burning, was associated with the 
accumulation of leaf litter under tree and with the 
regeneration of herbs and shrubs in exposed areas. An 
increased growth of fungi was recorded after the burning.  

The decrease in the soil microorganisms 2 and 4 weeks 
after burning coincided with the onset of high temperature 
and increased exposure of the study area to climatic 
extremes that was created artificially by setting the study 
area on fire. Most soil inhabitants are poorly adapted to 
survive the periods of low moisture and high 
temperatures, particularly, in moist forest environments. 
Many soil microorganisms have poor control of water loss 
because they lack an impermeable cuticle particularly, 
some fungi species like Aspergillus rapens, Umbelopsis 
spp., Starchybotrys spp. and mycotypha spp. 
(Vanwansen et al., 1998) which were present in the study 
area. Future use of fire in management of forest should 
be based on a sound knowledge of its potential impact 
upon components of the community. Both short and long 



 
 
 

 

term studies of the soil microorganism’s species com-

position of communities, and their response to fire, are 

urgently required. 
 

 

CONCLUSIONS AND RECOMMENDATION 

 

1. Microorganism (bacteria and fungi) abundance 
increases from forty-two days after burning. 
2. An increase in soil pH values increases the diversity 
and abundance of bacteria. 
3. Agroforestry farmer should ensure they slash and burn 

their farmland forty-two days before planting in other to 
enable the soil to fully regain their microorganisms and 

fertility back. 
 

 
REFERENCES 
 
Adekunle VAJ (2002). Inventory Techniques and models for yield and 

tree species. Diversity assessment in Ala and Omo Forest Reserves. 
S.W. Nigeria. Unpublished Ph.D. Thesis, 2002, Federal University of 
Technology, Akure, pp: 186.  

Ahn PM (1979). The optimum Length of Planted Fallow. In. Mongi, H.O. 
and Huxley, P.A. (Eds) Soil Research in Agroforestry. Proceedings of 
an expert Consultation held at the international council for Research 
in Agroforestry (ICRAF). Nairobi, Kenya.  

Akobundu IO (1987). Weed Science in the Tropics: Principles and 
practices. Wiley Interscience, New York.  

Alexander M (1997). Introduction to soil Microbiology, 2nd edition, New 
York, John Wiley and Sons Inc., Pg 467. 

Altieri MA (2002). Agroecology: the Science of natural resource 
management for poor Farmers in marginal Environment. Agric. 
Ecosyst. Environ., 93(1-3): 1-24. 

Atlas JS (1984). The Maturity index: an ecological measure of 
environmental Disturbance Based on soil microorganism species 
Composition, 83:14-19. 

Brandy P, Weil KE (1990). Earthworm activities and the soil system.  
Biol. Fertility Soil. 6:237-251. 

 
 
 
 

 
Eyasu E, Scoones J (1998). Perspective on soil fertility change: A case  

study from Southern Ethiopia. Land Degradation Dev., 10: 195 - 206.  
Huhta V (2001): Effects of Prescribed burning upon soil microbes, 

arthropods, Nematode Populations in coniferous forest soil, Acta 
Zoological Fennica, 4: 87-145. 

Giardiama CP, Sanford RL, Rersmith IC, Jaramillo VJ (2000). The 
effects of slash and burn on ecosystem nutrient during the land 
preparation phase of shifting cultivation. Plant Soil, 220: 247-260. 

Lai R (1997): Soil degradation effects on slope length and tillage 
methods on alfisols in Western Nigeria, soil physical properties. Land 
Degradation Dev., 8: 325-342. 

Nwoboshi LC (1982): Tropical Silviculture, principles and Techniques.  
Ibadan University Press, UI, Ibadan Nigeria.  

Nye PH, Greenland DJ (1990)): The soil under shifting cultivation. 
Technical Communication 51, Commonwealth Bureau of Soil, 
Harpenden, UK. 

Okojie JA (1996) Once upon a Forest. A masterpiece of creation. 
UNAAB Inaugural Lecture series, 1: 29. 

Reichle DE (1997): The role of Soil invertebrates in nutrient cycling, Soil 
organisms as Components of ecosystems. Ed. V. Lohm, and T. 
Person, Swedish Natural Science Research Council, Stockholm. 

Rhode AM, Hartmam BJ (1980) Investigation into possible feeding 
relationship between soil fauna and soil microbes. Pg. 25: 16-19.  

Seasted TR, Crossley DA (1980) Effects of microorganisms on the 
seasonal Dynamics of Mineralization process. Ann. Rev. Entomolol., 
29: 25-46. 

Smith CJ, People MB, Keerthisingle G, James TR (1994) Effects of 
surface Application of lime Gypsum and phosphogypsum on the 
alleviating of surface and sub-surface acidity in a soil under pasture 
(5): 995 ISSN 0004-9573.  

Vanwansen MB, Davis PR, Harris JRW, Longstaff BC (1998) A 
profusion of species? Approaches towards understanding the 
dynamics of the populations of the microorganisms in decomposer 

communities. The 20
th

, Symposium of the British Ecological society. 
London, Blackwell Sci. pubs. Oxford.  

Whelan RJ, Landedyk W, Pashby AS (1980). The effects of Wildfire on 

arthropod Populations in Jerrah Banksia Woodland, Western 

Australian Naturalist. 14: 214-220. 


