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UNIVERSITI PUTRA MALAYSIA
THE FINANCIAL FEASIBILITY OF RETAINING WALLS AND WINBREAKS AS MEASURES OF OIL CONSERVATION IN WADI
ZABID, YEMEN
ALLADEEN MOHAMAD ABDALLA AL-SHARJABI.
FH 2004 1
To all those people whom
I love, respect and in debt to.
Abstract of thesis presented to the Senate of Universiti Putra Malaysia in hlfilment of the requirements for the degree of Doctor of Philosophy
THE FINANCIAL FEASIBILITY OF RETAINING WALLS AND WINDBREAKS AS MEASURES OF SOIL CONSERVATION IN WADI
ZABID, YEMEN
BY
ALLADEEN MOHAMAD ABDALLA AL-SHARJABI
May 2004
Chairman: Associate Professor Awang Noor Abd. Ghani, Ph.D.
Faculty: Forestry
Wadi Zabid is one of the major agricultural areas of Yemen that faces serious soil
erosion (SE) problem caused by water and wind. Some of the farmers in the area
have constructed retaining walls (RW) and windbreak (WB) to conserve their
farmland soil but many do not. As the SE is becoming serious and soil conservation
activity is not progressing, there is a need to reveal the feasibility of soil conservation
investment, obstructions to soil conservation and farmers SE perception.
Data for this study were collected through questionnaires during the agricultural
season of 199912000. The total sample was 264 comprising four groups; i.e., "with"
and "without" RW and "with" and "without" WB. The financial benefit cost analysis
was the analytical technique and the decision criteria used were the net present value
(NPV), internal rate of return (LRR) and benefit cost ratio (BCR). Order logit and
logistic models have been applied to reveal farmers characteristics related to the
perception of the soil erosion and to the decision of soil conservation, respectively.
The study found that the farmer age, number of family working force and number of
permanent labourers all have positive relations with the serious perception of soil
erosion by water. However, the family size, RW length and farmer experience all
have shown negative relations. The model of RW adoption showed that farm-home
distance, neighbours complaints and the minor perception of soil erosion by water
have positive relation. On the contrary, the size of rented area and farm-market
distance both have shown negative relations with RW adoption. In the perception of
wind erosion model, the farming period, numbers of WB, presence of demoplots and
awareness of soil conservation programmes all have shown positive relations.
However, the farmer experience, WB age and neighbours complaints all have shown
negative relations with the perception. Nonetheless, the farmer will not plant WB
unless he is aged, literate, has more family working force, asked by neighbours and
has attended the extension night gatherings. The size of the family and the size of
rented farm area have shown negative relations with the adoption of WB measure.
In addition, the study found that the investments in RW and WB have been
financially feasible. The farmer who has invested in RW has got Yemen Riyals
(YRs) 33,652 as NPV (US$l= YRs 150). In term of BCR and IRR the farmer returns
are 1.14 and 14 percent, respectively. The farmer who has invested in WB has got
YRs 54,190 as NPV and 1.8 and 27 percent as BCR and IRR, respectively.
Therefore, as RW and WB proved to be financially feasible then government
subsidies are justified and will attract more farmers to conserve their farmland soil. In
addition, as the determinants of the perceptions of water and wind erosion are not
identical then separate strategies and extension programmes are justified.
PERPUSTAKAAN SULTAN ABBUC SAMN) IJNIVERGITI PUTRA MALAYSlA
Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk Ijazah Doktor Falsafah
KEBERUNTUNGAN DINDING PENAMBAK DAN PERINTANG ANGIN BAG1 PEMULIHARAAN TANAH DI WADI ZABID, YEMEN
Oleh
ALLADEEN MOHAMAD ABDALLA ALSHARJABI
Mei 2004
Pengerusi: Profesor Madya Awang Noor Abd. Ghani, Ph.D.
Fakulti: Perhutanan
Wadi Zabid sebagai salah satu kawasan pertanian terbesar di Yemen, menghadapi
masalah hakisan tanah serius yang disebabkan oleh air dan angin. Hanya sesetengah
petani telah membina dinding sebagai penambak (RW) atau perintang angin (WB)
sebagai langkah kawalan, manakala sebahagian besar tidak berbuat begitu.
Memandangkan masalah hakisan tanah menjadi semakin serius dan tiada usaha untuk
menghalangnya, maka adalah perlu di kaji potensi pelaburan bagi pemuliharaan
tanah, halangan pemuliharaan tanah dan persepsi petani terhadap status hakisan
tanah.
Data kajian telah dikumpul melalu sessi soalselidik pada musim pertanian
199912000. Sejumlah 264 petani daripada empat kumpulan respoden merangkumi
kumpulan 'dengan' dan 'tanpa' dinding penambak, dan 'dengan' dan 'tanpa'
perintang angin. Teknik yang digunakan adalah analisis faedah kos sementara kriteria
pemilihan adalah melalui nilai bersih semasa (NPV), kadar pulangan dalaman (IRR)
dan kadar faedah kos (BCR). Model order logit dan logistic digunakan untuk
menentukan ciri-ciri petani berkenaan persepsi terhadap hakisan tanah dan keputusan
berkenaan pemuliharaan tanah.
Secara ekonominya, kajian mendapati kedua-dua pelaburan untuk dinding penambak
dan perintang angin adalah wajar. Petani yang melabur di dalam (RW) beroleh Yrs
33652, 1.14 dan 14 peratus masing- masing bagi NPV, BCR dan IRR. Petani yang
menganggap hakisan air adalah serius berada dalam kumpulan berumur, tenaga ke rja
keluarga yang ramai, pekerja kekal yang lebih dan mempunyai RW yang kurang di
ladangnya. Bagaimanapun petani tidak akan membina RW kecuali dia mempunyai
dan menyewakan kawasan ladang yang kecil, jauh dari tempat tinggal tetapi dekat
dengan pasar, menganggap hakisan sebagai ancaman kecil, tidak rnengambil
bahagian didalam program pengembangan malam dan mendapat gesaan dari jiran.
Petani akan menganggap hakisan angin sebagai serius jika dia berpengalaman,
ladangnya dekat dengan pusat pengembangan dan plot demonstrasi, sedar akan
program pemuliharaan, mendapat gesaan jiran, mempunyai lebih WB dan telah
menanam WB untuk jangkamasa yang lama. Bagaimanapun, keputusan untuk
memilih WB ditentukan oleh faktor umur petani, celik huruf, jumlah tenaga kerja
keluarga, keluasan ladang, jumlah sessi pengembangan yang dihadiri, jarak ke pusat
pengembangan dan pasar, keselamatan hakrnilik tanah dan gesaan jiran. Petani juga
cenderung untuk membina WB jika bilangan ahli keluarga kurang dan menganggap
hakisan tanah sebagai masalah kecil.
Memandangkan RW dan WB satu pelaburan yang menguntungkan, maka sejumlah
kecil subsidi kerajaan dikira wajar dan akan menarik lebih ramai petani untuk
memulihara tanah pertanian mereka. Selain itu, strategi berasingan dan program
pengembangan untuk kedua-dua jenis hakisan yang berbeza adalah perlu
memandangkan perbezaan faktor-faktor yang berkaitan persepsi terhadap hakisan dan
langkah-langkah adoptasi pemuliharaan tanah.
vii
ACKNOWLEDGMENTS
Firstly and foremost, all praises and thanks are due to Allah; and peace and blessings
are upon His Trustworthy and Honest Messenger. I would like here to state my deep
thanks to the Chairman of my Supervisory Committee Associate Professor Dr.
Awang Noor Abd. Ghani for his guidance, advices and constructive criticism
throughout the course of this study. My thanks and gratitude are also due to the
members of the Supervisory Committee Associate Prof. Dr. Rush Bin Mohd and Dr.
Khamuruddin Mohd Noor for their valuable comments, guidance and constructive
thoughts. My thanks are extended also to the Independent Examiner Prof. Dr.
Dudung Darusman, the Chairman of the Examination Committee Prof. Dr. Ahmad
Said Sajap, the Internal Examiners Assoc. Prof. Dr. Ahmad Husni Bin Mohd. Hanif
and Dr. Jamaluddin Basharuddin for their valuable comments and suggestions.
I would like to thank Prof. Dato' Dr. Sheikh Omar Abdul Rahman and Assoc. Prof.
Dr. Mohd Azmi Omer for their unlimited generosity, continuous support and
assistant. I would like to thank to all members of the Faculty of Forestry in UPM but
special thanks are for Associate Prof. Dr. Ahmad Ainuddin and Associate Prof. Dr.
Lai Food Sea for their cooperation and permission that allow me to use the space in
the Hydrology laboratory. I also want to thank Mr. Mahmoud Yousif and Ahmat Bin
Madsoum for their cooperation and assistance. I would like to thank, as well, the
Directorate of Forests and Desertification Control, the Ministry of Agriculture and
Irrigation in Yemen and the Food and Agriculture Organisation for nominating me
and administrating my fellowship.
. . . V l l l
I have special thanks and good prayers to my late father, whom I lost during the
course of this study. My thanks are also due to all of my family members starting
with my mother and ending with the lovely baby, Yaser. Last but not least, I have
special thanks and prayers to my brothers Abdulrahman, Abdulhafeed and Abdullatif,
my cousin Dr. Ahmad Shamsan, my dear friends Dr. Mohammed Ugool and Eng.
Fahmi Qaid, Ali Alsaleemi, Yahyia Alsurabi, Eng. Mohamad Alassar and Eng.
Mohamad Hassan, whom I indebt a lot for their support and assistances in all
possible ways.
1 certify that an Examination Committee met on 5" May 2004 to conduct the final exmination of Alladeen Mohamad Abdalla Al-Sharjabi on his Doctor of Philosophy thesis entitled "The Financial Feasibility of Retaining Walls and Windbreaks as Measures of Soil Conservation in Wadi Zabid, Yemen" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows:
AHMAD SAID SAJAP, Ph.D. Professor Faculty of Forestry Universiti Putra Malaysia (Chairman)
AHMAD HUSNI BIN MOHD, Ph.D. Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Member)
JAMALUDDIN BASHARUDDIN, Ph.D. Lecturer Faculty of Forestry Universiti Putra Malaysia (Member)
DUDUNG DARUSMAN, Ph.D. Professor Laboratory of Forestry Socb-economics and Policy Faculty of Forestry Kampus Institut Pertanian Bogor (IPB) Darrnaga Indonesia (Independent Examiner)
School of ~ r i d u a t e Studies Universiti Putra Malaysia
Date: 9 > \ ~ \ 0 1
This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as hlfilment of the requirement for the degree of Doctor of Philosophy. The members of the Supervisory Committee are as follows:
AWANG NOOR ABD. GHANI, Ph.D. Associate Professor Faculty of Forestry Universiti Putra Malaysia (Chairman)
RUSLI MOHD, PH.D. Associate Professor Faculty of Forestry Universiti Putra Malaysia (Member)
KHAMURUDDIN MOHD NOOR, Ph.D. Lecturer Faculty of Forestry Universiti Putra Malaysia (Member)
AINI IDERIS, Ph.D. Professor/ Dean School of Graduate Studies Universiti Putra Malaysia
Date: 1 6 AUG 2004
DECLARATION
I hereby declare that the thesis is based on my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.
- ALLADEEN MOHAMAD ABDALLA AL-SHARJABI
Date:
xii
LIST OF ABBREVIATIONS
ADB
BCA
BCR
CBCA
c o s
CP
CS
cv
EBCA
ES
EV
FA0
FBCA
GDFDC
INB
IRR
MA1
NARR
NPV
PBP
PPI
PS
Asian Development Bank
Benefit cost analysis
Benefit cost ratio
Conventional benefit cost analysis
Consumer surplus
Cut-off period
Compensating surplus
Compensating variation
Economic benefit cost analysis
Equivalent surplus
Equivalent variation
Food and Agriculture Organisation of the United Nations
Financial cost benefit analysis
General Directorate of Forests and Desertification Control
Incremental net benefit
Internal rate of return
Ministry of Agriculture and Irrigation
Net average rate of return
Net present value
Pay-back period
Potential Pareto-improvements
Producer surplus
. . . Xlll
SBCA
SC
SCM
SE
SRTDA
sv
TDA
UNDP
WB
WRW
WTA
WTP
WtRW
WtWB
WWB
YRs
Per unit area
Retaining wall
Sensitivity analysis
Social benefit cost analysis
Soil conservation
Soil conservation measure
Soil erosion
Southern Region of Tihama Development Authority
Switching value
Tihama Development Authority
United Nations Development Programme
Windbreaks
With retaining wall
Willingness to accept
Willingness to pay
Without retaining wall
Without windbreaks
With windbreaks
Riyal of Yemen
xiv
TABLE OF CONTENTS
Page
DEDICATION ABSTRACT ABSTRAK ACKNOWLEDGEMENTS APPROVAL DECLARATION LIST OF ABBREVIATIONS LIST OF TABLES LIST OF FIGURES
CHAPTER
INTRODUCTION General Background Problem Statement Justification of the Study Objectives of the Study Organization of the Thesis
GENERAL BACKGROUND OF YEMEN Introduction Geographical Situation and Population Climate of Yemen
Soil Temperature Rainfall
Socio-economic Activities Agriculture Livestock and Grazing Fishing
The Problem of Soil Erosion The Soil Conservation Efforts The Yemen Economy
Characteristics of Yemen Economy Development Plans Economic Problems and Reforms
LITERATURE REVIEW Introduction Population and Resources
The Poverty Link Population and Soil Degradation Link Population and Food Scenarios
. . 11 ... 111
v . . . V l l l
X
xii . . . X l l l
xix xxii
Soil Resource and Threats Sustainable Agricultural Development Desertification and Land Degradation Causes of Soil Degradation The Impacts of Soil Erosion Mechanism of Soil Erosion
Soil Conservation Aspects Techniques of Soil Conservation Policy of Soil Conservation Role of Incentives and Subsidies Criteria of Successful Soil Conservation Projects
Investment in Soil Conservation The Feasibility of Soil Conservation Models Used for Conservation Feasibility Implications of Benefit Cost Analysis
Soil Conservation and Farmers Behaviours Dependent Factors in Soil Conservation Models Independent Factors in Soil Conservation Models
Summary
BENEFIT COST ANALYSIS: A Theoretical Background Introduction History of Benefit Cost Analysis The Social Welfare Foundations of BCA
Consumer Welfare Theory Consumer Welfare Measure Producer Welfare and Producer Surplus Social Welfare Measures and Choice
Types of Benefit Cost Analysis Conventional Benefit Cost Analysis Social Benefit and Cost Analysis
Benefits and Cost Determination Calculation of Benefit and Cost Sources of Errors in BCA Conceptual Strength of BCA Critics and Limitations of BCA
Economic Decision Criteria Benefit-Cost Ratio Net Present Value Internal Rate of Return
Summary
RESEARCH METHODS Introduction The Conceptual Framework The Study Design
The Study Site Population Sample Selection Sampling Procedure
xvi
VII
Computation of Costs and Benefits The Cost of Retaining Walls The Costs of Windbreaks Benefits of RW and WB The "With and "Without" Approach Cash Flow
Modelling Farmer's Behaviours on Soil Conservation Farmer's Perception of Soil Erosion Farmer's Decision on R W N B Adoption Description of the Models' Variables
Data Collection Questionnaire Design, Pre Testing and Reliability Structured Interview
Data Analysis Descriptive Statistics t- Test INB and "With" and "Without" Approach Sensitivity Analysis and Switching Value
FARMING CHARACTERISTICS AND SOIL CONSERVATION BEHAVIOURS Introduction Farmers Socio-economics Characteristics
The Household Age Profile The Household Size Household Working Force Literacy Farming Experiences
Farm and Farming Characteristics Farm Size Ownership Farming Period Size of Rented and Shared Farm Area Rent and Share Justifications Farming Characteristics of Wadi Zabid Agricultural Requirements and Soil Conservation Enthusiasm Farmers' Willingness to Conserve the Agricultural Soil Justifications for Loan Objections
The Farmers' Behaviours Towards Soil Conservation The Perception of the Water Erosion Severity The Determinants of Adoption of the RW Measure The Perception of Wind Erosion Severity The Determinants of Adoption of WB Measure
THE FINANCIAL FEASIBILITY OF SOIL CONSERVATION IN WADI ZABID Introduction Benefits and Costs of Soil Conservation Measures
Benefits of Retaining Walls
xvii
Benefits of Windbreaks Analysis of the Soil Conservation Cost
Analysis of the Investment in Soil conservation in Wadi Zabid
Performance of Farms "WRW" versus Farm "WtRW Performance of Farms "WWB" versus Farm "WtWB"
Sensitivity Analysis The RW Sensitivity Analysis for The WB Sensitivity Analysis for
Switching Values Analysis The RW Switching Values The WB Switching Values
VIII CONCLUSION AND POLICY IMPLICATIONS Introduction Prospects of Soil Conservation Investment Policy Implications
Soil Conservation Policy Implication for Soil Conservation Extension Implication for Research in Soil Conservation
Limitation of the Study
REFERENCES APPENDICES BIODATA OF THE AUTHOR
xviii
LIST OF TABLES
Table
2.1 Climatic Regions of Yemen
2.2 Land uses Classifications and Percentage
2.3 Yemen Cultivable and Cultivated Areas (000 ha)
2.4 Main Crops and Quantity of Production (000 tomes)
2.5 Livestock Resources (000 heads)
2.6 Annual GDP in Percentage for 1996-2001 (as percentage)
2.7 Yemen Gross Domestic Product and Gross National Product
2.8 Balance of Trade 199 1-2000 (000 YRs)
2.9 Financial and Monetary Indicators (as Pct of GDP)
4.1 Conventional and Social Benefit Cost Analysis
5.1 A Tally of Farms in Wadi Zabid Agricultural Centres
5.2 Sample Size According to Centre and SCM
5.3 Classification of Centres according to the Type of Erosion
5.4 The RW Construction Costs
5.5 WB Species, Numbers and Seedlings Costs
5.6 Cost of Windbreaks Planting and Equipment
5.7 Windbreaks Irrigation Frequency and Costs
5.8 Annual Costs of Windbreaks Maintenance
5.9 The Benefit of Crop Production Increment
5.10 Windbreaks Pole and Firewood Production
Page
2.4
2.8
xix
Table
5.1 1 Descriptions of the Models' Variables
Distribution of Wadi Zabid Farmers' Age
Distribution of Household Size in Wadi Zabid
Distribution of Family Working Force in Wadi Zabid
Distribution of Literacy Among Wadi Zabid's Farmers
Page
5.32
6.5 Distribution of Farmers' Farming Experiences 6.7
6.6 Distribution of Farm Size Ownership 6.9
6.7 Distribution of Farming Period in Wadi Zabid 6.1 1
6.8 Distribution of the Size of Rented and Shared Farm Areas 6.1 1
6.9 Distribution of the Justifications for Farmland Renting and Sharing 6.12
6.10 Major Characteristics of Farming Activities in Wadi Zabid 6.14
6.1 1 Farmers' Agricultural Requirements in Wadi Zabid 6.19
6.12 Distribution of Farmers Willingness in Soil Conservation
6.13 Justifications to Reject Loans for Soil Conservation
6.14 Reasons to Refrain fiom Government Soil Conservation Project
6.15 The Determinants of the Perception of severe Water Erosion
6.16 The Determinants of the Adoption of RW Measure
6.17 The Determinants of the Perception of severe Wind Erosion
6.18 The Determinants of the Adoption of WB Measure
7.1 Banana Land Preparation Costs (YRs)
7.2 Land Preparation Costs for Sorghum Crop (YRs)
7.3 Land Preparation Costs for Banana Production (YRs)
7.4 Differences in Quantity of Crops Production (Kglmaad)
Table
7.5 CottonISorghum Land Preparation Costs (YRs)
7.6 Differences in Quantity of Crops Production (Kgmaad)
7.7 Windbreaks Pole and Firewood Production
7.8 RW Establishment Costs
7.9 WB Establishment Costs
Page
7.7
7.10 Cash Flow for the Farm b'With" and "Without" Retaining Wall 7.15
7.1 1 The Net INB for the Retaining Walls at Different Economic Criteria 7.16
7.12 Cash Flow for the Farm "With" and "Without" WB 7.18
7.13 The Net INB for the Windbreaks at Different Economic Criteria 7.19
7.14 The RW Sensitivity Analysis 7.22
7.15 The WB Sensitivity Analysis 7.25
7.16 The RW Switching Values 7.29
7.1 7 The WB Switching Values
xxi
LIST OF FIGURES
Figure
2.1 Geographical Situation of Yemen
2.2 The Average Monthly Rainfall Distribution in Yemen
2.3 The Rainfall Map of Yemen
2.3 The Vegetation Map of Yemen
4.1 Dupuit Surplus
4.2 Consumer Surplus
4.3 The Four Measures of Welfare Change
4.4 The Producer Surplus
5.1 Soil Erosion and Conservation Framework
Page
2.2
xxii
CHAPTER I
INTRODUCTION
General Background
Soil is an essential natural resource for the production of food that supports human
life. However, the soil resource is exposed to many threats that lowered its potential
for food production. One of the greatest problems that the soil resource is facing is
the soil degradation. Oldeman (1994) defined soil degradation as human induced
phenomenon that lowers the current andlor future capacity of the soil to support
human life. The major forms of soil degradation are the soil erosion that initiated by
water and wind actions. Usually, it is hard to draw a line that would segregate the
term of soil erosion from soil degradation as the terms are interchangeably used to
describe the same thing. However, Morgan (1 995) defined soil erosion as the process
that detrimentally affects the soil essential properties and subsequently reduces crop
production and the farmer income.
Soil erosion is a worldwide problem that goes back to the time when man began
cultivation of the land. The main factors of the soil erosion are wind and water, and it
has become widely accepted to use the terms of water and wind erosion to distinguish
between soil erosion that caused by water and wind, respectively. Nevertheless, water
erosion is a major problem in non-arid regions while wind erosion is the major
problem in the arid regions, because of the combined effects of drought and
overgrazing. However, it is not unusual to notice both types in a country of relatively
small area.
The soil erosion leads to the loss of topsoil and reduction in soil productivity;
however the data that quantify such reduction are varied in quality and relevance
(Schertz et al., 1989). The effects of severe forms of erosion such as desert
encroachment and gully erosion are easy to be identified, but a small change in the
topsoil layer caused by soil erosion action might go on for years without notice. The
use of fertilisers and improved seeds/seedlings varieties have in many times hidden
the effect of soil erosion and prolonged the time to realise the reduction in crop
productivity and loss of fertile topsoil. In addition, soil erosion deteriorates the soil
production potential by affecting its physical characteristics.
The impacts and losses caused by soil erosion are striking. Kovda (1983) reported
that 430 millions hectares of productive land worldwide have been destroyed by the
soil erosion process and every year there is a loss of 5 to 7 million hectares of land
due to soil erosion (Clarke, 1994). Unless efficient measures are applied to control
soil erosion, the world will face a difficult time to meet the increasing population
food requirement. The danger of soil erosion exaggerates when it is realized that the
rate of soil erosion and population growth rate both are high in developing countries
that already have many problems. These entails questions like: how would the
coming generations meet the demand for food? Is there is enough land to produce
sufficient food quantity? Does the existing land will continue to produce the same
food quantity? What are the chances for protecting and reclaiming the existing land?
Nonetheless, considering soil as a non-renewable resource then controlling erosion
would become an ethical obligation for this generation to the hture generations or an
expression of land stewardship.
Problem Statement
Due to the diversity in Yemen physiographic characteristics two major forms of soil
erosion; i.e., water and wind erosion, can be identified. Yet, the available old terrace
system has implied that soil erosion by the runoff water is an old problem compared
to the soil erosion by the wind action (Scholte et al., 1991). The problem of wind
erosion has advanced in recent decades due to incidences of drought, over-grazing
and tree over-cutting in the marginal lands. In contrast, the two major forms of soil
conservation measures in Yemen are retaining walls (RW) and windbreaks (WB).
The former, RW, is a form of terrace system to control soil erosion by runoff water.
The WB is a group of trees planted in certain arrangements to reduce the wind speed
and to protect the farm land soil from blowing wind.
The impact of soil erosion (SE), either by runoff water and/or wind, will be noticed
first at the farm level as the soil characteristics will experience gradual changes till it
become economically and ecological unsuitable to support crop production.
However, the uses of fertilisers have succeeded in compensating the loss of soil
nutrients but not the changes in the soil characteristics. Moreover, the SE impacts at
the macroeconomics level will be through the raising in the imported fertilizers and
food bills. In sever SE incidences, farmers will abandon their farm lands and quit
farming, which would mean that the rate of unemployment will proliferate then
negatively affect the society welfare.
The government efforts in controlling the SE have been initiated in the early years of
the 1980's. The government efforts have been in forms of technical assistant,
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