ABSTRACT
A soil survey and fertility mapping of Okoko Item in Bende Local Government Area of Abia State,was carried out for efficient fertilizer use and crop production. The study was undertaken because Okoko Item is a major food producing community in the State The farmers are facing the challenges of scarcity and high cost of fertilizers as well the increasing declining soil fertility due to population pressure on the land and poor soil management. The study area covered 1, 885.5 ha. A free survey method of soil survey was adopted. The results showed that four soil mapping units ( Okoko 1, Okoko 11, Okoko 111 and Okoko 1V) were delineated and classified. Okoko 1 (1,202 ha) occupies a non gravel to gravelly level plain. The soils are shallow to moderately deep. Okoko 11 (230.5ha) are sandy to loamy and well drained and occours on elevation 116-209m above sea level. Okoko 111 (227.2ha) occupied loamy to clayey soils on undulating topography with rock outcrops. Okoko 1V (224.9ha) are deep, well drained coarse loamy that dominated by grssland vegetation. The soils are generally acidic, ranging from strongly acid while the (pH 5.00 – 5.50) to very strongly acid (4.50 – 5.00). Total N and exchangeable K ranged from low to medium (0.08 – 0.20 % N) and (0.06 – 0.24 cmol/ kg K) while available P ranged from medium to high (15 - 45 mg /kg P). Majority of the soils are arable Class II (1657.4ha) 128.1ha are non arable while soils occuring within the summit (128 - 137 m above sea level) belong to Class IV land. Three land capability units: Class IIew, Class IIen and Class Ives were delineated based on the degree of limitations (soil depth, rock out-crop and boulders; wetness, soil erosion and low nutrient) to sustainable crop production. Generally, it is concluded that the soils are arable but the choice of crops will differ based on the capability units. The soils at the northern end (towards Ugwueke) are of medium fertility while the soils at the southern end (towards Igbere) are of low fertility.The soils were characterized and classified using USDA Soil Taxonomy and correlated with World Reference Base (WRB). Four soil mapping units viz: Okoko I, Okoko II, Okoko III and Okoko IV were delineated and classified as Mollic Endoaquents (USDA); Eutric Gleysols (Humic)(WRB), Typic Rhodudults (USDA); HaplicAcrisols (Loamic)(WRB), Typic Plinthudalfs (USDA); Pisoplinthic Plinthosols (Clayic) (WRB) and Rhodic Paleudults (USDA); Haplic Acrisols (Loamic) (WRB), respectively The land capability map and soil fertility maps are recommended as visuals in extension education, as well as planning tools for agronomist, farmers and policy makers for sites selection for crop production, and as a guide for fertilizers use within Okoko Item community.
TABLE OF CONTENTS
Title
Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Tables
of Contents vi
List
of Tables ix
Lists
of Figures x
List
of Plates xi
Abstract xii
CHAPTER
1: INTRODUCTION 1
1.1 Background
of the Study 1
1.2 Statement of the Problem 3
1.3
Justification 4
1.4 Objectives
of the Study 4
CHAPTER 2: LITERATURE REVIEW 6
2.1 Sustainable Land Management 6
2.2 Land
Capability Classification (LCC) 7
2.3 Soil
Resource Literacy 11
2.3.1 Solution to soil resources illiteracy 12
2.4 Soil
Fertility Mapping 15
CHAPTER 3: MATERIALS AND
METHODS 17
3.1 Description
of the Study Area 17
3.1.1 Climate 17
3.1.2 Vegetation and land
use 19
3.1.3 Geology 19
3.1.4 Field study 20
3.2 Soil Laboratory
Analyses 23
3.2.1 Particle
size analysis 23
3.2.2 Chemical
analysis 24
3.2.3 Soil
pH determination 24
3.2.4 Organic
carbon 24
3.2.5 Total nitrogen 24
3.2.6 Available
phosphorus 25
3.2.7 Exchangeable
acidity 25
3.2.8 Total
exchangeable bases 26
3.2.9 Effective
cation exchange capacity 26
3.2.10 Percentage
base saturation (BS) 26
3.2.11 Soil
classification 26
3.3 Data Analyses 27
CHAPTER
4: RESULTS AND DISCUSSION 28
4.1 Soil
Mapping Units 28
4. 1 .1 Morphological
properties 30
4.2 Particle
Size Distribution of the Soils 35
4.3 Chemical Properties 38
4.4 Soil Classification 49
4.5 Land
Capability Classification 52
4.6
Soil Fertility Mapping 55
CHAPTER 5: SUMMARY, CONCLUSION AND
RECOMMENDATIONS 62
5.1 Summary 62
5.2 Conclusion 63
5.3 Recommendations 63
References
Appendix
LIST OF TABLES
PAGE
4.1: Morphological Properties of the soils 32
4. 2: Morphological
Properties of Mapping Unit Okoko III and Okoko IV 33
4.3: Particle
Size Distribution of Soils 37
4.4: Chemical
Properties of Mapping Unit Okoko
I 39
4.5: Chemical
Properties of Mapping Unit Okoko
II 41
4.6: Chemical
Properties of Mapping Unit Okoko
III 45
4.7: Chemical
Properties of Mapping Unit Okoko
IV 47
4.8: Taxonomic Classification of the Soils 51
LIST OF FIGURES
PAGE
3.1: Map of the Study area (Okoko Item) 18
3.2: Map
Showing Profile Pit Locations 22
4.1: Soil
Map of Okoko Item Showing Soil Mapping Units. 29
4.2: Land
Capability Classification Map of Okoko Item 54
4.3: Soil pH Map of Okoko Item 56
4.4: Total
N fertility map of Okoko Item 57
4.5 Available
P map of Okoko Item 59
4.6 Map of Ecxhangeable K of Okoko Item 60
LIST OF PLATES
PAGE
A:
Profile Pit of Okoko I 72
B: Profile
pit of Okoko II 75
C:
Profile Pit of Okoko III 78
D:
Profile pit of OKIT IV 81
E: Gravel,
stones and boulders in Okoko IV 82
CHAPTER 1
INTRODUCTION
1.1
BACKGROUND OF THE STUDY
Soil
is the foundation of every living thing (Chukwu, 2016). It's
a standard property resource, that serves man in many ways whether during a
comparatively undisturbed state or during a extremely disturbed state. Soils
are referred to as the last resting place throughout the rites of passage for
earthly bodies. Alternative functions of soil include: Other functions of soil include;
- sustaining activity, diversity and
productivity (habitat and gene pool, food and fibre production) of soil
biological components
- filtering, buffering,
immobilization, and removing toxic organic and inorganic substances storing, and cycling of nutrients and other substances;
- providing support for
socioeconomic structures like buildings, roads, etc, and acts as a
narrator of events in physical and cultural environment
- source of raw materials;
- acting as carbon pool to mitigate climate
change, and vi. Protection
of anthropological and earthly treasures related to human habitation
(Karlen et al., 1997; Costantini
and Giovanni, 2010).
Natural
classification of soils is very helpful in understanding and remembering the
behaviour and properties of soils. It also plays a crucial role in
communication among soil scientists and between them and other stakeholders in agricultural land use
within a community, and from one location to another. However, taxonomic
classification of the soils conveys little or no information to many land users
such as farmers, agronomists, agricultural extension specialists, etc. These land users are more interested in
how the soil will respond to management and manipulation. According to Ogunkule
and Babalola (1986) they want to know the following:
- i the use for which a piece of land
is best suited for or the relative suitability of the land or parts of it
for alternative uses:
- the important crops that can be grown
for profit, and
- limitations for one use or several alternative
uses and how they can be overcome.
Land
capability classification groups soils for arable crop production based on
their limitations and inherent capabilities and helps to assess suitability of
land for the cultivation of crops.
All these indicate high affinity between mundane world and soils, and establish contingencies for soil
awareness drive to access rural and urban
landscape, to arouse passion and longing
for their continuous use and
land management. This may deter
soil and land misuse and associated tragedy of the commons (Chukwu and Agugo,
2006). The
foregoing make pedological data fundamental in minimizing food insecurity
through appropriate use of sustainable soil management systems (Fasina et al.,
2015). Godfray et al.; (2010) predicted
that the requisite to feed 9 billion people by 2050 can partly be met by
closing the productivity gap and enhancing the production margin of
agriculture. As a consequence, information about soils of any area is cardinal
for successful and sustainable agriculture. Nigeria and other countries in sub Saharan Africa, cannot achieve
sustainable food security without sustainable land management. Ability to decipher the soil data
correctly will guarantee good land use planning and thorough application of
other inputs to attain sustainable soil management decisions, to intensify agro
- technology transfer, and overall agricultural development.
1.2 STATEMENT
OF THE PROBLEM
Although the agricultural policy of Nigeria
published in 1988 recognized the need to allocate land to its most suitable
uses, nevertheless, present land use does not take into consideration the best
use of land. Dudal (1987) emphasized that pedology facilitates international
communication, guides the development of new technologies and accelerates their
applications. These roles will continue to increase as demographic pressure
creates more demand on the soil resource base. There is a
widespread apathy for soil and inefficient soil management due to poor
knowledge of soil data interpretation (Chukwu et al., 2010). Quantitative
pedology is based on Soil Taxonomy (Soil Survey Staff, 1999) and the parameters
measured have been selected as necessary for classifying soils as natural
bodies. Through soil surveys, the pedon is
scaled up to appropriate spatial scales. Differences in quantitative pedology
are important to establish the broad picture of soils as natural bodies. The limitation of Soil Taxonomy is that it only
quantifies permanent soil attributes considered important for soil
classification. The Soil Taxonomy (ST)
ignores many inherent or dynamic attributes crucial to plant productivity and
important for soil fertility mapping (Carating,
2007).
Part of the aftermath is that despite large
expanse of land devoted to food crop production, the huge amount of resources
of labour, capital and management invested, outputs still remain low (Fasasi,
2007). According to the Federal Ministry for Agriculture (Ogbe, 2016) the current Agriculture Promotion Policy (APP)
(2016 – 2020) of Nigeria is a strategy by the Buhari administration to solve our inability to meet domestic food
requirements and an inability to export at quality levels required for market
success. The former problem is a productivity challenge driven by an input system
and farming model that is largely inefficient. According to National
Council on Agriculture and Rural Development (NCARD, 2016), the current system
of blanket fertilizer use results in a colossal waste of scarce fertilizer
investment because the soil is not well prepared to take the nutrients for root
interception within its short lifespan of arable cropping. Another problem is
that agricultural development is limited by a weak link between agricultural
research and farmers (Osborn, 1996).
Pedologists could strengthen
the linkage between researchers and farmers by translating soil survey reports
into interpretive soil maps such as soil fertility maps and land capability
maps, which are more easily usable by farmers (Chukwu and Okonkwo, 2015). Christoplos
(1995) described extension as communication. Consequently, such interpretive
soil maps are communication channels (visual aids) and important tools to
facilitate transfer of information from a source to a receiver. The maps are
simplified and self explanatory that most extension agents and literate farmers
can understand and use them unaided.
1.3 JUSTIFICATION
Soil fertility mapping based on soil map and using
soil profile sampling is advocated for areas that involve hundreds if not
thousands of hectares. The same profile sampling methodology can also be used
for geostatistical analysis through computer-assisted interpolation (kriging)
to come up with isarithmic map of the soil fertility factor if one desires to
dispense with the soil map as the basis of delineation (Carating, 2007). There is a dearth of information of
such interpretive soil maps at community levels in Nigeria and none exists for
Okoko Item.
1.4
OBJECTIVES OF THE STUDY
The major objective of the study was to produce
land capability map and soil fertility maps of Okoko Item for efficient soil management
and crop production.
The specific objectives were to:
i.
conduct a soil survey of the study area;
ii.
show the distribution of soils in the area,
iii.
present the characteristics of the soils of
the study area,
iv.
produce land capability map of the area for
sustainable crop production, and
v.
delineate
soil fertility maps of the area for efficient fertilizer use.
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