Design of a geographic information supported database for the management of pressurised irrigation systems at the plantation du Haut Penja, Cameroon

RESUME

La plupart des données relatives aux systèmes d'irrigation peuvent maintenant être caractérisés géographiquement. Une étude orientée vers la création d'une base de données géographiques (SIG) pour la gestion des systèmes d'irrigation sous pression a été effectuée à la "Plantation du Haut Penja". Le système d'irrigation de ce groupe devient très complexe et diversifié en raison de l'augmentation du nombre d'hectares de bananiers cultivés chaque année. Les objectifs spécifiques de l`étude étaient de: développer une base de données pour un accès rapide et un stockage méthodique des informations relative a ce système d'irrigation; développer des couches thématiques pour le SIG; évaluer les besoins en eau de chaque parcelle; évaluer le fonctionnement des réseaux et de représenter spatialement certains aspects du fonctionnement du système d'irrigation. La base de données sur le système d'irrigation a été créée à l'aide de Microsoft Access 2003 tandis que les différentes couches du SIG ont été créées à l'aide du logiciel MapInfo 8.0. Une connexion objet de base de données (ODBC) a été créé entre la base de données MS Access et le logiciel SIG MapInfo pour effectuer des requêtes sur le système d'irrigation et représenter certains éléments spatiaux du système d'irrigation. Un total de 35 tables, 10 formulaires et 17 requêtes ont été créés pour la base de données afin d'améliorer la saisie et la récupération des données. Le calcule de la probabilité de satisfaction des besoins en eau des cultures de 20 ans de données climatiques pour une profondeur effective des racines de 50 cm, ces besoins étaient de 40 mm/semaine pour une satisfaction des besoins en eau des cultures 1 an sur 20. En fonction de l'évapotranspiration des cultures et de l'efficacité des pluies de la veille, les demandes en eau des cultures seront ajustées dans la base de données. Les couches thématiques pour les SIG, telles : les variétés de cultures, la disposition spatiale des cultures, types de sols, le type de système d'irrigation, la répartition des précipitations et d'autres ont été créés dans la base de données. Certaines de ces couches ont été représentées spatialement en utilisant le logiciel MapInfo 8.0. L'analyse des débits, pressions, vitesses d'écoulement et d'autres propriétés hydrauliques du réseau a montré que les conditions limites d`écoulement dans les conduites sont respectées. Cela indique davantage qu`un accent devrait être mis sur la gestion de ce système ; d`où la nécessité d`un outil tel le SIG développé dans le cadre de la présente étude en vue d`améliorer la gestion du système.

ACKNOWLEDGEMENTS

Knowledge is like a cult which quickly withers away when there are no disciples, comforters nor supporters. It is in this like that I will like to appreciate those who have been instrumental to me during this period of scholastic rummaging. This list is a non exhaustible one which I`ll like to use to show appreciation:

To the Almighty God Who has given me the opportunity to become what I am today and who has guided and directed me all the days of my life.

To my supervisors, Prof. Fonteh Mathias who has always guided me in most of my academic work and Mr. Njila Roger who put efforts together to see that this work becomes a reality and for the time they visited me on the field. I`ll forever be grateful to them for the knowledge on database management they`ve imparted on me.

To my field supervisor, Mr. Boa Apollinaire, thank you wouldn`t just be enough for me to offer you. You gave in all you could for me to carry out my internship without stress and you were always in there to guide me, sometimes till late at night. This and many other things you did for me during this six month period are enough reasons for me to be thankful.

To Mr. Tsimi Hiliare Zoa, Director of Human Resources at PHP for the partnership created with the department of agricultural engineering which gave rise to this internship. This goes a long way to show the contribution of your company to the training of young Cameroonians in the agricultural sector.

To Mr. Jean Yves Regnier, Mr. Tchoumba Jules, Mr. Ndosse Robert, Mrs. Guenaelle Renovolt, Mr. Andjengo Emmanuel all senior workers of PHP, for the technical advice I received from them during this period and for all the logistics they provided me with.

To Dr Berinyuy Joseph and Mr. Tekounegning whose comments have always been very valuable, I owe much honour.

To the lecturers of the Faculty of Agronomy and Agricultural Sciences and especially those of the Department of Agricultural Engineering, who have inculcated into me much knowledge in the domain of agronomy.

To Mr. Marin Mahop, of the Department of Agricultural Engineering for his availability in giving us the technical advice we`ve always needed during this period.

To Prof. Ajaga and family, Dr. Focho and Family, Fonteh`s Family, Dr. Ayissi and family for their wise counsel, advice and for moral encouragements.

To my mates and friends of the 12^th batch of FASA and particularly those of the department of agricultural engineering, for the wise complements and advice bestowed on each other during these years we`ve spent together.

To my very dear friends Muyang Achah, Etubo Constance, Ngalim Olive, Chiato Maryben, Eseinei Paul, Tenkang Ernest, Kilain Fru, Lebaga Eloy, Tarla Divine, Fointama Nyongo, with whom I had much joy and struggles during my course period in Dschang.

To Mr. Ewome Hardison for the hospitality he showed me all through my stay with him in Njombé. Mr. Fongoh Wilson and Family, Mr. Fonbah Cletus, Mr. Fondi Emmanuel for making me not feel homesick during this period of intense stress.

DEDICATION

To my parents Mr. and Mrs. Azah who have relented none of their efforts in seeing me
through my educational career and to whom I owe much

To my brothers, Teku Elvis and Boubga Clifford and my sister, Wansho Gilda for the

love and solidarity that we express towards each other

To Late Dr. Ambe Fokwa, for all the advice I received from him during my years of work with him at the Department of agricultural Engineering and may He find Profound Peace in the Almighty

TABLE OF CONTENTS

LIST OF TABLES xii

LIST OF FIGURES xiii

LIST OF ABBREVIATIONS, ACRONYMS AND SYMBOLS xiv

CHAPTER I INTRODUCTION 1

1.1 Background of the Study 1

1.2 Problem Statement 3

1.3 Objectives of the Study 4

1.4 Importance of the Study. 5

CHAPTER II LITERATURE REVIEW 7

2.1 Banana 7

2.1.1 Introduction 7

2.1.2 Ecology 8

2.2 Definition of some Terms and Concepts related to Irrigation 10

2.3 Evapotranspiration 13

2.3.1 Measurement of evapotranspiration 15

2.3.2 The Penman-Montheith equation 15

2.3.3 Meteorological factors determining evapotranspiration 16

2.4 Maximum Production 18

2.5 Pressurized Irrigation Systems 19

2.5.1 Sprinkler irrigation systems 19

2.5.2 Micro irrigation systems 20

2.6 Irrigation Scheduling and Management 21

2.6.1 Irrigation management 21

2.6.2 Irrigation scheduling 21

2.6.3 Importance of irrigation scheduling 24

2.7 Geographic Information Systems 24

2.7.1 Data acquisition and representation 26

2.7.2 Advantages and disadvantages of vector and raster data 28

2.7.3 Steps used for the putting in place of a GIS project 29

2.8 Databases 30

2.8.1 Database management systems 32

2.8.2 Relational databases 33

CHAPTER III MATERIALS AND METHODS 36

3.1 Description of the Study Area and Experimental Site 36

3.1.1 Geographical Location 36

3.1.2 Relief 36

3.1.3 Hydrology 36

3.1.5 Vegetation 39

3.1.6 Climate 39

3.1.7 Soils 40

3.2 Description of the Irrigation System at the PHP Group 40

3.2.1 Pumping station 41

3.2.2 The main line (Pipes) 41

3.2.3 Distribution network 43

3.3 Development of the Database for the Irrigation System 44

3.3.1 Data review 45

3.3.2 Entity and attribute identification 45

3.3.3 Table and key creation 46

3.3.4 Definition of relationships and referential integrity 47

3.3.5 Creation of data entry and retrieval forms 48

3.4 Development of thematic layers for the GIS 50

3.5 Calculation of the water requirements in each plot 51

3.5.1 System requirements 51

3.5.2 Crop requirement 52

3.6 Evaluation of the Functioning of the Network 53

3.6.1 Calculation of flow rates 54

3.6.2 Calculation of flow velocity and head losses. 54

3.6.3 Determination of available and required pressures 55

3.6.4 Calculation of piezometric elevations 57

3.7 Spatial Representation of some Aspects on the Irrigation System 58

CHAPTER IV RESULTS AND DISCUSSIONS 60

4.1 Database for the Irrigation System 60

4.1.1 Physical model 60

4.1.2 Creation of forms 62

4.2 Thematic layers for the GIS 63

4.3 Water requirements in each plot 66

4.3.1 System requirements 66

4.3.2 Crop water requirements 67

4.4 Simulation of the Functioning of the Network 69

4.5 Spatial Representation of some Queries on the Irrigation System 70

4.5.1 Spatial representation of crop coefficients 70

4.5.2 Spatial representation of some plot valves 71

4.5.3 Theissen polygon for rainfall heights on the plantation 72

CHAPTER V: CONCLUSIONS AND RECOMMENDATIONS 74

5.1 Conclusions 74

5.2 Recommendations 75

5.2.1 Improvement of the system 75

5.2.2 Further research 75

REFERENCES 76

APPENDICES 82

LIST OF TABLES

Table 2.1	Length of crop growth developmental stages for various planting periods	Pages
	and Climatic regions	14
2.2	Monthly KC values of Banana for tropical climate	15
2.3	Set of related fields in an irrigation system which form a record	31
2.4	Comparing DBMS and Relational DBMS (RDBMS) terms	32
3.1	Average annual precipitation of Njombé (2004-2008)	39
4.1	Thematic layers needed for water balance calculations	63
4.2	Thematic layers for non-descriptive data	64
4.3	Thematic layers for non-descriptive data ...	65
4.4	Probability of satisfaction of irrigation requirements (requirements in mm)	68
4.5	Irrigation dose (mm) for two irrigation systems.	69

LIST OF FIGURES

Figure		Pages
2.1	Morphology of a banana plant...	8
2.2	One-to-one relationship of databases.	35
2.3	One-to-many relationship of databases.	35
3.1	Geographical location of Njombé	37
3.2	Aerial view of PHP cultivation areas in the Njombé Plantations	38
3.3	Monthly rainfall histogram for Njombé in 2008	40
3.4	Principal Irrigation Pipes at the PHP group	42
3.5	Architecture of the GIS database	45
3.6	Creation of table in design mode in MS access	46
3.7	Definition of relationships in the physical data model	.48
3.8	Selecting fields to be included in the production plot form under the form
	assistant mode	..49
3.9	Irrigation map for a production plot developed with AUTOCAD 2004	51
3.10	Query created in MS access to obtain the water requirements of the system	52
4.1	Presentation of the physical model of data as developed in MS Access	.61
4.2	Form for data entry and retrieval for the production plot	.62
4.3	System water requirement as calculated in MS access	.66
4.4	Sensibility of various plots to water stress with respect to Kc	71
4.5	Plot valves for two irrigation plots ...	...72
4.6	Repartition of rainfall depths in the plantation	73

LIST OF ABBREVIATIONS, ACRONYMS AND SYMBOLS

BLOB: Binary Large Object

cp: Specific heat of the air

CSQL: Compact Standard Query Language

D: Zero plane displacement height [m],

DBMS: Database Management System

e_a : Actual Vapour Pressure [KPa]

e_s: Saturation Vapour Pressure[KPa]

ESRI: Economic and Social Research Institute

G: Soil heat flux

GIS: Geographic Information System

INGRES: Intelligent Graphic Relational System

JPEG: Joint Photographic Experts Group

P: Depletion factor

PHP: Plantations du Haut Penja

PS: Photosynthesis

r_a: Aerodynamic Resistance [sm^-1],

RAW: Readily Available Water

RDBMS: Relational Database Management System

RGB: Red, Green, Blue

R_n: Net solar radiation

r_s: Bulk? Surface Resistance

SPM : Société des Plantations de Mbanga

SQL: Standard Query Language

TIF: Tagged Image File

ã: Psychometric Constant

Ä: Slope of the saturation vapour pressure temperature relationship

ñ_a: Mean air density at constant pressure

Z_m height of wind measurements [m],

Zh height of humidity measurements [m],

Zom: roughness length governing momentum transfer [m],

Zoh: roughness length governing transfer of heat and vapour [m],

K: Von Kerman`s constant, 0.41 [-],

U_z: wind speed at length at length z [ms^-1].

CHAPTER I
INTRODUCTION

1.1 Background of the Study

Bananas are presently the world`s fourth most important food commodity in terms of gross value of production (Lemeilleur et al., 2003). Banana cultivation is a major source of foreign exchange and continues to be one of the principal agricultural activities for most developing countries of Africa, Latin America and the Caribbean. World production of bananas (dessert and plantain bananas) is estimated at some 40 to 60 million tons. Some 7-8 million tons (mostly dessert bananas) are exported to the developed countries yearly (Pedro et al., 2003). The banana industry has been designed and oriented almost exclusively towards the export market (Yamileth, 1998). As merchandise for exportation, bananas contribute principally to the economy of a number of countries with low income, such as Ecuador, Honduras, Guatemala, Cameroon, Ivory Coast, and the Philippines (Pedro et al., 2003).

About 700 000 tons of bananas are produced annually in Cameroon by three main companies: the Plantation du Haut Penja? (PHP) Group, Del Monte, and the Société des Plantations de Mbanga? (SPM) (Anonymous, 1998). This production yielded 103 billion FCFA during the 2001-2002 financial years for an investment of 12 billion 108 million FCFA (Anonymous, 2003).

The production of this crop at an industrial scale entails the use of much water. Farms require water for irrigation in the dry season and packing stations use water for washing bananas. Fonteh and Assoumou (1996) describe irrigation as the supply of water to crops in a climate in which rainfall does not meet the crop water requirements during all or part of the growing season. Tiercelin (1997) defines irrigation as the artificial use of water to ameliorate yields or crop production. The same author states that more than one-third of the world`s food is produced through irrigated agriculture. About 280 million ha of land are irrigated around the world with an annual increase of four to five thousand hectares yearly (Rieul et al., 1992).

Irrigation could be total or supplemental. In total irrigation, provision is made for all plant water needs. This is the case in regions where no rainfall can be relied upon during all

or part of the crop growing season. Supplemental irrigation is practiced in areas where a crop can be grown by natural rainfall alone, but additional water improves yields and quality (Fonteh and Assoumou, 1996). The following are reasons why crops could be irrigated:

1. Supply water for plant growth where none could grow before or to get better growth or extend the growing season, all leading to increased yields.

2. To improve quality (Robinson, 1981).

3. As an insurance policy against drought such that if water will affect the returns on high investments on seeds, fertilizers, etc., then irrigation is planned for.

4. Sprinkler irrigation is used for temperature control:

· Frost protection: in very low temperatures, the water from a sprinkler on plants freezes, giving off the latent heat of fusion.

· Evaporative cooling: in hot weathers, water from sprinklers evaporates, absorbing the latent heat of evaporation form the atmosphere around the plants, leading to a drop in temperature.

5. To leach unwanted salts building up in the top soil.

6. Reduce soil strength at the start of the dry season for easy cultivation.

7. For the application of chemicals (chemigation) or fertilizers (fertigation). Robinson (1981) presents the following specific advantages of irrigating bananas:

· Well irrigated banana plants have turgid pseudostems, are vigorous, with a high resistance to wind and diseases;

· Irrigation favors the application of fertilizers especially during dry periods;

· The life span of an irrigated banana plot is higher than that of a non irrigated plot;

· Irrigation promotes the continuous production cycle of bananas;

· Irrigation improves the quality of fruits, increases the length and width of banana fingers, helps in obtaining higher grades and in the development of large bunches (15 to 18 hands).

In Cameroon, bananas are irrigated during the dry seasons. During these periods, there is little or no rainfall to provide the plant water requirements (Ewane, 2008). Irrigation is therefore resorted to as a means of supplying the crop water requirements and

to improve the yield and quality of bananas during these dry periods. Robinson (1981) showed that yields increase by 20-30 tons per hectare of banana in Natal, South Africa when additional water was supplied at fourteen days intervals. Further increase from 60-80 % in extra quality was recorded compared to non- irrigated banana plantations. Three forms of irrigation are currently practiced in banana plantations around the world namely; surface irrigation, sprinkler and drip irrigation (Stover and Simmonds, 1987). Trials in South Africa have shown that drip and micro sprinkler irrigation systems have each outperformed the others irrigation systems in yields and in water economy (Robinson and Alberts, 1987).

Many new technologies, such as remote sensing, geographic information system (GIS) and expert system, are now available for application to irrigation systems and can significantly enhance the ability of water managers (Mennati et al., 1995, Ray and Dadhwal, 2001).

There exists a global water crisis in the world in this century. Conscious of the situation of water crisis and other alarming statistics around the world, the Plantation du Haut Penja (PHP) attaches importance to the efficient management of its water resources. AQUASTAT (2009), for example, shows that, of the total water available on the earth`s surface, 97.5% is salt water and only 2.5% is fresh water. Of this 2.5% freshwater, 99% is locked up in glaciers, icebergs or underground and only 1% is available to the nearly seven billion humans and billions of other forms of life. It further gives a closer look to the situation in the Lake Chad area, which was once a landmark for astronauts circling the earth, but now difficult to locate. Surrounded by Cameroon, Chad, Niger, and Nigeria, the lake has shrunk by 95 % since the 1960s (AQUASTAT, 2009). The soaring demand for irrigation water in this area is draining dry the rivers and streams the lake depends on for its existence. As a result, Lake Chad may soon disappear entirely, its whereabouts a mystery for future generations. With this limited freshwater resource and the increasing competition for the resource, irrigated agriculture worldwide must improve the utilization of these water resources (Molden et al., 1998).