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DOI: 10.14738/tmlai.91.9824
Publication Date: 08th March, 2021
URL: http://dx.doi.org/10.14738/tmlai.91.9824
Volume 9 No 1
Evaluation of Soil Quality Status under Different Forest Tree
Species in Nigeria
Akanbi Olorunfemi Sunday Ojo1
, Onawumi Olufisayo Olayinka2 and Edibo, Gabriel Ojodale3
1 Soils and Plant Nutrition Section, Cocoa Research Institute of Nigeria,Ibadan, Oyo State, Nigeria. 2 Forestry Reseach Institute of Nigeria, Jericho, Ibadan, Oyo state, Nigeria
3
Agronomy Section, Cocoa Research Institute of Nigeria, Ibadan, Oyo State
akanbioso2008@gmail.com
ABSTRACT
A study was carried out at Forestry Research Institute of Nigeria, Ibadan, South -western, Nigeria in the
second quarters of 2018 to evaluate the current status and the distribution of some soil quality factors of
study area. The study also aimed at suggesting strategies for efficient management of the soil quality
factors in the study areas. Soil samples were collected under six (6) different forest trees species
plantations. The samples were subjected to routine laboratory analytical protocol for the determination
of both physical and chemical properties of the samples. Results implicated that the soil organic matter
(SOM) of the study area varied from one forest plantation to the other. However, SOM was found to be
highest under natural forest (NF) with a mean value of 3.90% while open field had the least with a mean
value of 1.62%. Similar results were observed for soil total nitrogen (N). There was a significant
(p<0.05)difference in the amount of exchangeable K contents (0.008cmol/kg) in soils under open field
with less ground cover and forest tree species relative to soils under NF, Nauclea dideirichi (ND) and
Mangifera indica (MI) respectively. Soils under NF significantly recorded the highest exchangeable Ca
compared to open field and others. It can therefore be concluded that good agricultural management
practises that will enhance soil quality factors and multi forest species cultivation be encouraged for
effective and efficient nutrient management systems in the forest ecosystems for enhancement of bio
diversities of both micro and macro organisms. However, due to population pressure on the available land
for other non-agricultural purposes coupled with annual bush burning, inadequate rainfall, lack of good
agricultural practices and non-availability of natural forest for farming, it has become imperative that
agroforestry system of farming in which trees or shrubs are grown in association with crops is advocated.
Keywords: Ecosystems, Forest, Nutrient, Soil quality factors.
1 Introduction
Soil according to FAO portal is defined as the natural medium for the growth of plants, a natural body
consisting of layers that are composed of weathered mineral materials, organic material, air and water:
an end product of the combined influence of climate, topography, organisms (Flora, Fauna and humans)
on parent materials (original rocks and materials) over time. Soil quality however, is the ability of soil to
provide, supply the required materials to planting and its ability to maintain and improve moisture and
air within the soil and support human being needs (Doran, Coleman, Bezdicek, and Stewart 1994).
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Transactions on Machine Learning and Artificial Intelligence Volume 9 , Issue 1, Feb 2 0 2 1
Copyright © Society for Science and Education United Kingdom 13
A major problem facing tropical agriculture is the inherently low fertility status of moist of the soils
because of the predominantly low activity kaolinitic clay type and soil organic matter. Soil fertility
according to young (1997) is the capacity of the soil to support plant growth under given climatic
conditions. Soil fertility maintenance therefore has been as concern in tropical Africa particularly with the
rapid population increase occurring in the past few decades with its associated continuous land use soil
organic matter status has been identified as one of the most important indicator of soil quality factor.
However, due to population pressure on the available land for other non-agricultural purposes coupled
with annual bush burning, inadequate rainfall, lack of good agricultural practices and non-availability of
natural forest for farming, it has become imperative that agroforestry system of farming in which trees or
shrubs are grown in association with crops is advocated.
The contribution of soil organic matter to overall performance of agricultural production and is positive
influence on the fertility of soil cannot be over emphasised. The word organic matter generally refers to
naturally occurring compound found in the atmosphere, aquatic and soil environmental. This therefore,
implies that organic matter occurs in virtually all naturally systems, SOM usually occurs as about 1-5% or
more of the top soil depending on the location and type of soil.
Objectives:
1: To evaluate the current status and the distribution of some soil quality factors of study area.
2: The study also aimed at suggesting strategies for efficient management of the soil quality factors in the
study area.
2 Materials and methods
The study which was conducted at Forestry Research Institute of Nigeria (FRIN) Idi-Ishin, Ibadan aimed at
evaluating soil quality status under different forest tree species in Nigeria. Idi - Ishin. Ibadan lies between
latitude of 070 101 N and longitude 030 521 E. It lies at an altitude of about 122 meters above the sea level.
It is in tropical rain forest zone. The total annual rainfall of about 1600mm was distributed over a period
between nine to ten months in a bimodal rainfall pattern. Early rain occurs between March to late July
and late rain occurs between August to October with five months dry season and a short day spell in
August (August break). The day season runs from early November to March with characteristic cool dry
northern wind and harsh scorching sun. The temperature of Ibadan is fairly high throughout the year with
minimum temperature usually ranges from 25.1o
C to 28o
C. Ibadan has a moderate high to very high
relative humidity throughout the year with a range of 46% to 89%. The soil temperature at Ibadan is
considered fairly high and ranges between 26o
C and 36o
C (Akanbi, 2016).
2.1 Soil sample collection techniques
Five different plantations contain each of tree species were selected for the study. The sites were
demarcated into two blocks depending on the shape, soil samples were collected on the demarcated
blocks in a stratified manner. Three soil samples were collected per augering points at nine different
locations per block in each of the plantation under study and adjacent plot (control) using bucket auger
at depths of 0 -15, 15 - 30 and 30 - 45cm at 25m apart. The sample were tagged, and dried, crushed and
allowed to pass through a 2.0mm mesh sieve. Sample collected from the adjacent open plot were equally
prepared same way and were subjected to both physical and chemical analysis. Mechanical analysis was
done using hydrometers method as describe by Bouyoucos (1957). PH was determined in water (1:2 soil:
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Akanbi Olorunfemi Sunday Ojo, Onawumi Olufisayo Olayinka and Edibo, Gabriel Ojodale; Evaluation of Soil Quality
Status under Different Forest Tree Species in Nigeria. Transactions on Machine Learning and Artificial Intelligence,
Volume 9 No 1 February (2021); pp: 12-18
URL:http://dx.doi.org/10.14738/tmlai.91.9824 14
water ratio) using a PH meter with glass electrode as described AOAC (1990). Organic carbon content was
determined using the Wakley - Black (Nelson and Somers, 1982) available Phosphorus determination was
done by Bray method described by Bray and Kurtz (1945). Total nitrogen (N) was determined by the
Kjedahl digestion procedure (Jackson 1962). Exchangeable bases were determined by extraction with
neutral ammonium acetate and the amount of K, Ca, Na in the filtrate were determined using Perkin
Elema Atomic Absorption Spectro - photometer (AAS). Exchangeable acidity was determined by soil
extraction with 1 neutral and titration with 0.05N NaOH using Phenolphthalein indicator as outlined by
IITA (1979).
2.2 Statistical analysis
The obtained data were subjected to analysis using Microsoft Office Excel for means and results presented
in charts with their error bars showing the differences in the treatments
3 Results and Discussions
The results of soil physical properties under the different plantations selected for the study indicated that
the %Sand contents ranged between 79.17 and 90.17 while the % clay and silt fractions ranged from 8.67
to 19.00% and from 1.17 to 6.50% respectively. The soil separates in the study area varied widely
indicating spatial differences in their parent materials. However, the textural classification was
predominantly sandy clay loam. The soils under MI; ND; GS and TS recorded the highest bulk densities in
descending order although the differences were not significant (p > 0.05). There were no significant (p <
0.05) differences in soil bulk densities found under OF; NF and IS but were significantly lower (p<0.05)
than the MI; ND; GS and TS. The relatively lowest bulk densities found under NF (0.38g/cm3
) and IS
(0.37g/cm3
) is an indication that NF and IS are able to loosen the soil under thereby creating more pore
spaces within the root rhizosphere thus creating more avenue for easy infiltration and aeration. This
observation agreed with Ziblim et al., (2012) who reported a lower bulk density under Teak grandis
relative to the other tree species and control.
3.1 Nitrogen (N)
Figure 1 presents the result of soil Nitrogen (N) under different forest tree species. The result indicated
that soil total N contents were highest under NF compared with other tree species and adjacent open
field. However, this was distantly followed by IS (0.89%) and ND (0.82%) respectively. Open forest and TS
recorded least N value of (0.53%) and (0.56%) respectively.
Figure 1: Soil Nitrogen under different forest tree species