relationships between soil physical properties and crop yields in different cropping systems in ...

162 Pages·2014·1.75 MB·English

FACULTY OF AGRICULTURAL SCIENCES
Institute of Plant Production and Agroecology in the Tropics and Subtropics
University of Hohenheim
Field: Plant Production
Prof. Dr. Georg Cadisch

RELATIONSHIPS BETWEEN SOIL PHYSICAL PROPERTIES AND
CROP YIELDS IN DIFFERENT CROPPING SYSTEMS IN SOUTHERN
CAMEROON

Dissertation
Submitted in fulfilment of the requirements for the degree
“Doktor der Agrarwissenschaften”
(Dr.sc.agr. / Ph.D. in Agricultural Sciences)

to the
Faculty of Agricultural Sciences

Presented by
Jacques Roberto Tueche
Stuttgart, Germany
2014
This thesis was accepted as doctoral dissertation in fulfilment of requirements for the degree
“Doktor der Agrarwissenschaften” (PhD in Agricultural Sciences) by the faculty of Agricul-
tural Sciences at the University of Hohenheim, Stuttgart, Germany on April 7th, 2014.

Date of oral examination: July 18th, 2014.

Examination Committee

Supervisor and reviewer Prof. Dr. Georg Cadisch

Examiner Prof. Dr. Karl Stahr

Additional examiner Prof. Dr. Torsten Müller

Faculty representative Prof. Dr. Thilo Streck

Co-supervisors
Dr. Lindsey Norgrove
Dr. Stefan Hauser

I
Dedication

To You, Jesus-Christ, with gratitude I dedicate this thesis begging that You may accept it.
You are the image of the invisible God, the One in whom the fullness of deity lives in bodily
form (Bible, Colossians 1: 15-20), the “Pedo-Agronomist”: The One Who First planted a
garden and “published His work” (Bible, Genesis, 2:8-9); The First Anesthesist and Trans-
planting Surgeon (Bible, Genesis, 2:21-22). Thank You for being my Heavenly Mentor.

II
Acknowledgements
This thesis was funded by IITA-Cameroon, by the research project of Dr. Lindsey Norgrove,
funded by the Robert Bosch Stiftung and myself. This work would not have been possible
without the support from a large number of people. First, I would like to thank my supervi-
sors:
Dr. Lindsey Norgrove, who admitted me in her research project, guided me in the field
work, gave me access to her personal library of more than 4000 references and reviewed some
of my manuscripts.

I am indebted to Dr. Stefan Hauser for facilitating my integration to IITA-Cameroon,
for the access to IITA’s resources and for his project which funded part of this thesis. He also
provided key scientific advice for field work, laboratory and statistical analyses and for re-
viewing my manuscripts.

I am very grateful to Prof. Georg Cadisch, who accepted to supervise this thesis, and
through whom my admission to the University of Hohenheim was made possible. He also
provided technical support, e.g. the access to Hohenheim University online library and de-
voted time to discuss and review some of my manuscripts and the final copy of this thesis.

I would like to thank the director general of IRAD Dr. N. Woin, the cooperation chief
of service Mrs. A.C. Ngo Tama, Ekona regional chief of centre Dr. K. Etchu, Mr. J. Bessong
and all my collaborators at IRAD-Ekona particularly those of soil laboratory for their key and
diversified support.

I am also indebted to all IITA-Cameroon staff, particularly Mr. Aboubakar Yakouba
(IITA-Cameroon, officer in charge) and Mrs. Monique Tegamtchoung (IITA, the secretary)
who provided cheerful administrative support; to R. Ndango, J.P. Edzoa, J. Chia, V. Zenkeng,
F, Abada and many others who have facilitated the use of IITA equipment, laboratories or
helped with soil sampling, analyses and fields management.

Thank you to the farmers which permitted us to conduct experiments in their fields.
Thanks to T. Ndzana, D. Essimi, J. Essah, S. Ndameda, E. Nanga, and X. Nkada for tomato-
maize fields’ management, monitoring and soil sampling.
Finally, I would like to thank: my wife Dr. Edith Tueche and our children Elisabeth,
Beraca and Emmanella, my father Michel Tueche, my mothers: Marie and Louise Tueche, my
brothers and sisters particularly my elder brother, Dr. S. Tueche whose scientific publications
in medical sciences were a real challenge to me; my friends and my beloved: Prof. Z. Fumum;
Madam E. Kouonang, Mr. J. Yougang, and Dr. D. Ngonge Mr. T. Andoseh for their love,
encouragement, the moral support, their prayers and patience during this program.
III
Table of contents
Dedication ................................................................................................................... II
Acknowledgements .................................................................................................... III
Table of contents ....................................................................................................... IV
Abbreviations ............................................................................................................. IX
1. General Introduction.............................................................................................. 2
1.1 The challenge to meet food demands of a rapidly growing population
in traditional agricultural production systems in the humid tropics .............. 2
1.2 Cameroon: Agro-ecological zones and management ................................. 4
1.2.1 The Sahelo-Sudanian savannah.................................................. 4
1.2.2 The high Guinean savanna .......................................................... 5
1.2.3 The mountain zone or Western Highlands ................................... 6
1.2.4 The humid forest with monomodal rainfall ................................... 6
1.2.5 The humid forest with bimodal rainfall ......................................... 6
1.3 Attempts to improve crop yields in the humid tropics and associated
constraints .................................................................................................. 8
1.3.1 Improved land/rain and runoff waters management ..................... 8
1.3.2 Soil fertility improvement .............................................................. 8
1.3.3 Mechanical tillage ........................................................................ 9
1.3.4 Crop improvement ..................................................................... 10
1.4 Soil physical properties: Importance and management ............................ 10
1.4.1 Soil texture ................................................................................. 10
1.4.2 Bulk density and soil cone penetrometer ................................... 11
1.4.3 Soil structure .............................................................................. 12
IV
1.4.4 Temperature .............................................................................. 13
1.4.5 Soil moisture and water retention .............................................. 13
1.5 Justification of the choice of plantain, tomato and maize for this study .... 13
1.6 Hypotheses .............................................................................................. 15
1.7 Objectives ................................................................................................. 15
1.8 Outline of the study ................................................................................... 16
2. Influence of different cropping systems on soil physical properties and
plantain bunch yield ............................................................................................ 18
2.1 Abstract .................................................................................................... 18
2.2 Introduction ............................................................................................... 19
2.3 Materials and Methods ............................................................................. 21
2.3.1 Study area ................................................................................. 21
2.3.2 Experimental layout ................................................................... 21
2.3.3 Determinations of soil physical properties ................................. 23
2.3.4 Plantain fresh bunch mass determination .................................. 25
2.3.5 Data analysis ............................................................................. 25
2.4 Results ..................................................................................................... 25
2.4.1 Soil physical properties before planting ..................................... 25
2.4.2 Changes in soil physical properties ........................................... 26
2.4.3 Plantain fresh bunch yield .......................................................... 31
2.4.4 Relationships between bunch yield and soil physical
properties ................................................................................... 32
2.5 Discussion ................................................................................................ 33
2.6 Conclusion ................................................................................................ 36
V
3. Maize (Zea mays L.) yield and soil physical properties as affected by the
previous plantain cropping systems, tillage and nitrogen application .................. 38
3.1 Abstract .................................................................................................... 38
3.2 Introduction ............................................................................................... 39
3.3 Materials and Methods ............................................................................. 40
3.3.1 Study area ................................................................................. 40
3.3.2 The previous plantain cropping systems .................................... 41
3.3.3 Maize seeding, tillage and fertilizer application .......................... 41
3.3.4 Observations at maize harvest .................................................. 41
3.3.5 Determinations of soil physical properties ................................. 42
3.3.6 Data analysis ............................................................................. 44
3.4 Results ..................................................................................................... 44
3.4.1 Maize yield parameters .............................................................. 44
3.4.2 Soil physical properties before and after tillage ......................... 47
3.4.3 Relationships between maize yield parameters and soil
physical properties ..................................................................... 49
3.5 Discussion ................................................................................................ 51
3.6 Conclusion ................................................................................................ 53
4. Tillage and varietal impacts on tomato (Solanum lycopersicum L.)
production on an ultisol in central Cameroon ...................................................... 55
4.1 Abstract .................................................................................................... 55
4.2 Introduction ............................................................................................... 56
4.3 Materials and Methods ............................................................................. 59
4.3.1 Location ..................................................................................... 59
4.3.2 Land preparation and experimental design ................................ 59
VI
4.3.3 Tomato husbandry, pest and disease control and data
collection .................................................................................... 60
4.3.4 Soil measurements .................................................................... 61
4.3.5 Data analysis ............................................................................. 62
4.4 Results ..................................................................................................... 63
4.4.1 Labour requirements for destumping and tillage ........................ 63
4.4.2 Tomato growth parameters, pest and disease assessments
and yield .................................................................................... 63
4.4.3 Weeds ....................................................................................... 66
4.4.4 Soil physical properties .............................................................. 67
4.4.5 Productivity gains through intensification ................................... 69
4.4.6 Correlations between soil physical properties and tomato
yield ........................................................................................... 71
4.5 Discussion ................................................................................................ 72
4.6 Conclusion ................................................................................................ 76
5. Residual effects of previous tillage system on maize growth and soil
physical properties in central Cameroon ............................................................. 78
5.1 Abstract .................................................................................................... 78
5.2 Introduction ............................................................................................... 79
5.3 Materials and Methods ............................................................................. 81
5.3.1 Location ..................................................................................... 81
5.3.2 Land preparation and experimental design ................................ 81
5.3.3 Maize growth and yield assessments ........................................ 83
5.3.4 Soil measurements .................................................................... 83
5.3.5 Data analysis ............................................................................. 85
5.4 Results ..................................................................................................... 86
VII
5.4.1 Maize yield and yield components ............................................. 86
5.4.2 Residual effects of previous land preparation on soil
physical properties in central Cameroon .................................... 89
5.4.3 Correlation maize yield and yield components with soil
physical properties ..................................................................... 90
5.5 Discussion ................................................................................................ 93
5.6 Conclusion ................................................................................................ 96
6. General Discussion ............................................................................................. 98
6.1 Do soil physical properties deteriorate under cropping in southern
Cameroon? ............................................................................................... 98
6.2 Is tillage or any land preparation intensification useful for crops yield
increase in southern Cameroon?.............................................................. 99
6.3 Does major investment in establishing improved cropping systems
improve profitability of subsequent crops? ............................................. 100
6.4 Do soil physical properties control crop yields in southern
Cameroon? ............................................................................................. 101
6.5 Outlook and recommendations ............................................................... 103
7. Summary ........................................................................................................... 106
8. References ........................................................................................................ 114
APPENDIX A. Additional publications ..................................................................... 135
A.1. Chromolaena odorata: the benevolent dictator? ........................................ 136
A.2. Tackling black leaf streak disease and soil fertility constraints to
expand Musa production onto short fallow land in Cameroon ................ 140
APPENDIX B. COURSES followed ......................................................................... 141
CURRICULUM VITAE ............................................................................................. 142
STATUTORY DECLARATION……………………………………………….………….146
VIII
Abbreviations
ANOVA : ANalysis Of Variance
AWC : Available Water Capacity
asl : above sea level
BD : bulk density
C : Carbon
oC : Celsius degree
Ca : Calcium
cm : Centimetre
CORR : Correlation
CR : cone resistance to soil penetration
CTA : Technical Centre for Agricultural and Rural Cooperation
Cu : Copper
FAO : Food and Agriculture Organization (of the United Nations)
Fe : Iron
g : Gram
GIC : Groupe d’Initiative Communautaire
GLM : General Linear Model
GMD : Geometric Mean Diameter
H : Hydrogen
h : hour
ha : Hectare
IITA : International Institute of Tropical Agriculture
IRAD : Institute of Agricultural Research for Development
K : Potassium
kg : Kilogram
km : kilometre
LUS : Land Use System
m : Meter
Mg : Magnesium
mm : Millimetre
MPa : mega Pascal
MWD : Mean Weight Diameter
N : Nitrogen fertilizer
n : number of observation
Na : Sodium
ns : not significant
O : Oxygen
P : Phosphorus
P : statistical significance testing
IX