ABSTRACT
This study was conducted to evaluate the soils of
Ibiono Ibom Local Government Area in Akwa Ibom State, Nigeria, through a
comprehensive soil survey and land suitability analysis for selected arable and
tree crops. The main aim was to characterize, classify, and assess the
suitability of the soils for the cultivation of cassava, maize,
plantain/banana, rice, cocoa, oil palm, and rubber. Fieldwork involved
delineating three major soil mapping units based on topography and elevation
gradients: 0–50 m (unit 1), 51–100 m (unit 2), and above 100 m (unit 3). Soil
profile pits were excavated in representative locations, and samples were
collected for detailed laboratory analysis. Laboratory procedures included both
physical and chemical analyses. Particle size was determined using the
Bouyoucos hydrometer method; chemical properties such as pH, total nitrogen,
organic carbon, available phosphorus, exchangeable acidity, and total
exchangeable bases were analyzed using standard procedures. Results indicated
significant variations in soil properties across the mapping units, reflecting
differences in drainage, texture, fertility status, and topographic position.
Soil mapping unit 1 was classified as Typic Epiaquept (Gleyic Cambisol), unit 2
as Aeric Epiaquept (also Gleyic Cambisol), and unit 3 as Typic Hapludult (Haplic
Acrisol). Land evaluation based on the parametric method revealed that all
mapping units were marginally suitable (S3) for plantain/banana and oil palm.
Cocoa was not suitable (N1) in any of the units due to acidity and fertility
limitations. Cassava was moderately suitable (S2) in unit 3 and marginally
suitable (S3) in units 1 and 2. Maize was highly suitable (S1) in unit 3,
moderately suitable (S2) in unit 2, and marginally suitable (S3) in unit 1.
Wetland rice was best suited to unit 1 (S2), marginal in unit 2 (S3), and not
suitable (N1) in unit 3. Rubber was only marginally suitable (S3) in unit 3. The
major limitations affecting suitability included poor soil fertility, drainage
challenges, and soil physical constraints, although climatic conditions were
generally favorable for crop production. It is recommended that soil fertility
management practices, including organic and inorganic amendments, be adopted to
improve crop performance. Strategic land use planning based on the suitability
classes can enhance sustainable agricultural productivity in the region.
TABLE OF CONTENTS
CHAPTER 1
INTRODUCTION
1.1
Background of the Study
1.2 Justification of the Study
1.3 Objective
CHAPTER 2
LITERATURE REVIEW
2.1 Concept of Soil Survey
2.2 Brief History on Soil Survey Development
In Nigeria
2.2.1 Purposes and uses of soil survey
2.2.1.2
Types of soil survey
2.2.1.3
Exploratory soil survey:
2.2.1.4
Reconnaissance soil survey
2.2.1.5 Detailed soil survey: Detailed soil surveys
identify more of the variation in soil
2.2.1.6
Intensive soil survey (Very detailed survey)
2.2.1.7 Soil
survey and mapping
2.2 Concept
of Land and Landuse.
2.2.3 Land use planning
2.2.4 Land utilization type
2.3 Soil Classification
2.3.1 Purpose of
soil classification
2.3.2 Soil classification
in Nigeria
2.3.3 Soil classification
in Akwa Ibom State
2.3.4 Land classification
and land use
2.4 Characterization
Of Soil
2.5 Land
Evaluation
2.5.1 Methods of land
evaluation
2.5.2 Parametric method
2.5.3 Qualitative
land evaluation
2.6 Soil
Suitability Evaluation
2.6.1 Methods
of evaluating land suitability
2.7 Land
Evaluation And Land Suitability
2.8 Physico-Chemical
Properties Of The Soil As Influenced By Different Land Use Systems
2.9.1 Soil texture
2.9.2 Soil bulk
and particle densities
2.9.3 Total
porosity
2.10 Soil Chemical Properties
2.10.1 Soil reaction (pH) and electrical conductivity
2.10.2 Soil organic matter and carbon
2.10.3 Total nitrogen
and carbon-nitrogen ratio
2.10.4 Available
phosphorus
2.10.5 Exchangeable
bases
2.10.6 Cations exchange capacity
2.10.7 Percentage
base saturation
2.10.8 Selected micronutrients
CHAPTER
3
MATERIALS
AND METHODS
3.1 Description
Of The Study Area
3.1.1 Location
of the study area:
3.1.2 Physiography
of the study area
3.1.3 Geology and
land forms of study area
3.1.4 Drainage
3.1.5 Climate
3.2 Vegetation And Land Use
3.3 Preliminary
Soil Mapping/Field Work
3.3 Sample
Preparation
3.4 Laboratory
Analyses
3.6 Soil
Classification
3.7 Data
Analysis
CHAPTER
4
RESULTS
AND DISCUSSION
4.1. Morphological
Characteristics of Soils of the Mapping Units
4.2. Physical Properties of Soils of the Mapping
Units
4.3 Chemical
Characteristics of Soils of the Mapping Units
4.4 Soil
Classification of the Mapping Units
4.10: Taxonomic Classification of Soils of the
Study Area
4.11 Land Evaluation
CHAPTER
5
CONCLUSION
AND RECOMMENDATIONS
5.1 Conclusion
5.2 Recommendations
References
Appendix 1: Profile
Pit Description
LIST OF TABLES
Table 3.1: Monthly
Rainfall of the Study Area (mm) 2006 to 2016
Table 3.2: Monthly
Mean Temperature (oC) of the Study Area (mm) 2006 to 2016
Table 3.3: Monthly and Annual Solar Radiation (MJm2 day-1) of the Study Area
(2006 -2016)
Table 3.4: Monthly
and Annual Relative Humidity (%) of the Study (2006 – 2016)
Table 3.6: Land quality and factor rating for
Cassava (Manihot Esculenta crantz)
Table 3.7: Land
quality and factor rating for maize (Zea Mays)
Table 3.8: Land quality
and factor rating for Plantain/Banana (Musa
spp) cultivation
Table3.9: Land quality and factor rating for wetland
rice (Oryza sativa)
Table 3.10: Land quality
and factor rating for cocoa (Theobroma
cacao) cultivation
Table3.11: Land quality
and factor rating for oil palm (Elaeis guinensis)
cultivation
Table 3.12: Land quality
and factor rating for Rubber (Havea brasiliensis)
cultivation
Table 4.1: Morphological characteristics of soils of
mapping unit 1 (IBOM 1)
Table 4.2: Morphological characteristics of soils of
mapping unit 2 (IBOM 2)
Table 4.3: Morphological characteristics of soils of
mapping unit 3 (IBOM 3)
Table 4.4: Physical characteristics of soils of mapping
unit 1 (IBOM 1)
Table 4.5: Physical characteristics of soils of mapping
unit 2 (IBOM 2)
Table 4.6: Physical characteristics of soils of mapping
unit 3 (IBOM 3)
Table:4.7: Chemical characteristics of soils of mapping
unit 1 (IBOM 1)
Table 4.8: Chemical characteristics of soils of mapping
unit 2 (IBOM 2)
Table 4.9: Chemical characteristics of soils of mapping
unit 3 (IBOM 3)
Table 4.11: Land
characteristics of the mapping units
Table 4.12: Suitability
Class Scores of the Soil Mapping Units for Cocoa (Theobroma cacao) Cultivation
Table
4.13: Suitability Class Scores of the
Soil Mapping Units for Plantain/Banana (Musa
spp) Cultivation
Table 4.14: Suitability
Class Scores of the Soil Mapping Units for Rubber (Havea brasiliensis) Cultivation
Table 4.15: Suitability
Class Scores of the Soil Mapping Units for oil palm (Elaeis guinensis) Cultivation
Table 4.16: Suitability
Class Scores of the Soil Mapping Units for cassava
(Manihot Esculenta crantz) Cultivation
Table 4.17: Suitability Class Scores of the Soil Mapping Units
for maize
(Zea Mays)
cultivation
Table
4.18: Suitability Class Scores of the
Soil Mapping Units for wetland rice (Oryza sativa) cultivation
LIST OF FIGURE
Figure 3.1: Map of Akwa Ibom State Showing the Study
Area
Figure 3.2: Map of Ibiono Local Government Area
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Soil
survey involves soil characterization, evaluation and soil mapping which
provides a powerful resource for the benefit of mankind especially in the area
of food security and environmental sustainability (Esu, 2004). Soil
classification is the systematic arrangement of soils into groups or categories
on the basis of their characteristics. Soil characterization studies are major
building blocks for understanding the soil, classifying it and getting the best
understanding of the environment. Characterization provides the information for
our understanding of the physical, chemical, mineralogical and microbiological
properties of the soil. Early
soil surveys were made to help farmers locate soils responsive to different
management practices and to help them decide what crops and management
practices were most suitable for the particular kinds of soil on their farms
(Soil Survey Staff, 1999).
A
sustainable land management is the one that does not degrade the soil. The
success in land management to maintain soil quality depends on the
understanding of how the soil responds to land use. This is because the rate of
soil quality degradation depends on land use, the soil types, topography and
climatic condition among these factors, inappropriate land use system
aggravates degradation of soil physico-chemical and biological properties. In
Akwa Ibom State, soil degradation due to inappropriate land use is threatening
the livelihood of millions of people (Udo, 2008). This is because soil is a
critically important component of the earth’s biosphere.
Land
evaluation is mainly the analysis of data about land containing soils, climate,
vegetation, and so forth, in terms of realistic alternatives for improving the
use of the land. The role of land evaluation
and, more recently, the quantification of soil quality are highly important for
good land management and sustainable use of land resources. Although ‘soil
quality assessment’ is often used as a misnomer for ‘land evaluation,’ both
could be regarded as the interpretative phase of soil survey. While land
evaluation is concerned with the assessment of land performance when used for
specified purposes, soil quality is defined as ‘the capacity of a specific kind
of soil to function, within natural or managed ecosystem boundaries, to sustain
plant and animal productivity, maintain or enhance water and air quality, and support
human health and habitation.’ In considering productivity, environmental
quality, and health as major functions of soil, this definition requires that
values be placed on specific soil functions as they relate to the overall
sustainability of alternate land-use decisions.
The basic needs of man such as food, clean
water, fuel, clothing, shelter etc are provided by land, which is in limited
supply (Doran, 2012). Land is the part of the earth's surface which includes
all physical elements such as climate, soil, forests, minerals, mountains,
lakes and animals (Meyer and Turner, 1992). Soil, a major and essential
component of land supplies water and nutrients to plants and provides stability
for roots. Soil acts as a store of minerals, organic matter, water and energy
and diverse chemical compounds. Soil provides an important habitat for
organisms, spending either whole or part of their life cycles in the soil (Lal,
2002). Soil acts as natural filter for
groundwater/drinking water. During the process of filtration, solid substances
are mechanically filters out of the percolating water, and binds to soil solid
(humus and clay) (UEIS, 2012). Soil serves as the foundation for building and
act as an aquifer recharge. Soil function as a transformer of substances as can
be seen in the transformation of heavy metals within the soil (UEIS, 2012).
Conversion of natural forest land into
cultivated land decreases organic matter content and affects the soil physical
and chemical properties. Improper land-use and soil management systems cause
soil degradation (Saraswathy et al., 2017). Many researchers reported
that conversion of natural forest land to cultivated farmland, deforestation,
overgrazing and excessive mineral fertilization caused significant changes in
soil properties (Conant et al., 2013; Tate et al., 2014; Fraterrigo et
al., 2015, Saraswathy et al., 2017). Therefore, improper
land-use and poor soil management resulted in land degradation, soil
deterioration and reduction in crop productivity.
Proper land-use systems and soil management
practices play significant roles in the reduction of soil loss and restoration
of soil fertility (Lal, 2010). Land-use change from annual crops to permanent
crops reduces the detrimental effect of soil tillage and agrochemical usage.
Permanent crops bring a valuable number of benefits such as water conservation,
nitrogen cycling and carbon sequestration of more than 50% when compared to
conventional crops (Liu et al., 2010). Land use and soil
management practices influence the soil nutrients and related soil processes,
such as erosion, oxidation, mineralization, and leaching, etc (Celik,
2005). It modifies the processes of
transport and redistribution of nutrients. In non-cultivated land, the type of
vegetative cover is a factor influencing the soil organic carbon content (Liu et al., 2010). Thus, land use and type
of vegetation must be taken into account when relating soil nutrients with
environmental conditions (Liu et al., 2010). Low crop yield and
environmental degradation caused by improper land use is a worldwide problem
that has attracted attention in sustainable agricultural production systems
(Vangen et al., 2006). Based on these
findings, the land should be evaluated based on physical and environmental
conditions such as quality and characteristics.
Suitability is a measure of how well the
qualities of the land unit match the requirement of a particular form of land
use. Land evaluation indicates to the degree of suitability for a land use
without respect to economic condition. It emphasizes of a relatively permanent
aspect of suitability, such as climate and soil condition rather than
changeable ones, such as prices, therefore the evaluation of land qualities for
suitability for crops emphasizes the land suitability evaluation, and component
of land unit for each agricultural crop. (Liu et al., 2010).This has
necessitated a yearning for decision leading to the most beneficial use of
limited land recourses. Evidence based decision made for optimal benefits of
land recourses have considerable implication for conserving land resources for
the future (Abah, 2013).
Land use evaluation determines land use option
which is important for land use planning. In Akwa Ibom state in general, and in
Ibiono Ibom in particular, increasing demographic pressure, ecological
problems, particularly soil erosion, in addition to oil spillage and
accelerated rural urban industrialization diminish available good agricultural
land.
Ibiono Ibom local government area in Akwa Ibom
State is located within the tropical rain forest belt which is often evergreen
in nature, and is characterized by tall trees and hard tropical trees with
thick ground cover. But on the contrary, urbanization and unsustainable
environmental practices have resulted in the disappearance of this ideal
vegetation type. Few of the tropical trees encountered in the suburbs are
either planted in homestead gardens or in abandoned farmlands. The area is now
in the modified rain forest locally known as the oil palm bush (Okon, 2018).
This vegetation type is dominated by wild growing palm trees, tall grasses and
secondary re-growth in abandoned farmlands for soil fertility restoration. Even
this vegetation type is fast disappearing as it is constantly being cleared for
road construction, building of houses and other land requirements of
urbanization. In fact, more than 70% of vegetation has disappeared while the
remaining 30% is found in small areas especially the periphery of the city
(Okon, 2018). Compound farmland is common in the area and is characterized by
annual farming with mixed and sequential cropping or monoculture (CRBDA, 1978).
This form of land use is found mostly in
Ibiono and Itu axis of the area, scattered trees including cocoa, oil palm,
mango and papaya make up this land use type. The area is used for annual
cropping with very short fallow periods. Crops planted include maize, plantain,
yam, banana, cassava and sweet potato (Ituen, 2017). Fresh water swamp forests
are largely found but not restricted to watercourses, which are made up of a
mosaic of grass plains, palm swamp, scrub and forest on water logged and
seasonally flooded soil. The prominent land use in this area is farming; human
intervention through agriculture, construction, environmental modification and
quest for fuel wood, timber, no timber forest product has greatly altered the
vegetation. This system has led to serious soil erosion particularly gully
development, hence, decline in soil productivity due to degradation of soil
physical and chemical property. It affects the soil structure and structural
indices including bulk density, total porosity and pore size distributions,
infiltration rate, aggregate stability among others. Therefore, there is
special need for soil survey and land evaluation in Ibiono Ibom Local
Government Area to ensure sustainable crop cultivation, high crop productivity,
reduction in land degradation and increased in environmental safety. Such
evaluation may be for selected arable and permanent crops commonly cultivated
in the area. This would promote effective land-use planning.
1.2 JUSTIFICATION OF THE STUDY
Improper land-use and soil management systems
cause’ soil degradation and inability of soil to perform effectively its
ecosystem functions (Saraswathy et al., 2017). Rapid decrease in
agricultural lands due to urbanization and industrialization is a phenomenon
which is observed worldwide, including Akwa Ibom State. The construction of
industrial establishments, roads, sports facilities and entertainment centres
etc, on fertile agricultural lands resulted in rapid decrease in agricultural
lands. The use of agricultural land for non-agricultural purposes generally
takes place on the fertile agricultural lands which are generally Class I to
Class IV agricultural lands. In these classes of given land-use where any plant
can grow, they are plain, well-drained, and the soil depth is high. In this
way, urbanization, one of the most serious threats for the world’s
biodiversity, permanently alters land use in Nigeria. Also, agricultural land-use
and soil management systems have been generally adopted without recognizing
consequences on soil properties, soil fertility and environmental quality, and
therefore significant decline in agricultural soil quality has occurred (Imeson
et
al., 2016).
The
results of exploiting land-use systems without consideration of the
consequences on soil quality have cause much environmental degradation. Other
non-agricultural uses, such as industrial and urban uses, also have important
negative consequences on soil quality, due to local contamination, soil
sealing, and changes in the dynamics of the landscape systems (Imeson et
al., 2016). The preservation of soil quality lies in practicing sustainable
land use and soil management systems, to balance productivity and environmental
protection. Hence, there is need to investigate the suitability of soils of
Ibiono Ibom Local Government Area for selected arable and tree crops
cultivations for effective land-use planning select and adopt the best land-use
options.
1.3 OBJECTIVE
The main
objective of the study is to conduct soil survey and land evaluation of Ibiono
Ibom L.G.A for arable and tree crop production.
Specific
objectives were to:
(i) characterize and classify soils of
Ibiono Ibom Local Government Area of Akwa
Ibom State
(ii) evaluate
the suitability of the soils for production of four arable crops (cassava,
maize, plantain/banana, rice) and
three tree crops (cocoa, oil palm and rubpber)
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