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,