Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25
Page 26
Page 27
Page 28
Page 29
Page 30
Page 31
Page 32
Page 33
Page 34
Page 35
Page 36
Page 37
Page 38
Page 39
Page 40
Page 41
Page 42
Page 43
Page 44
Page 45
Page 46
Page 47
Page 48
Page 49
Page 50
Page 51
Page 52
Page 53
Page 54
Page 55
Page 56
Page 57
Page 58
Page 59
Page 60
Page 61
Page 62
Page 63
Page 64
Page 65
Page 66
Page 67
Page 68
Page 69
Page 70
Page 71
Page 72
Page 73
Page 74
Page 75
Page 76
Page 77
Page 78
Page 79
Page 80
Page 81
Page 82
Page 83
Page 84
Page 85
Page 86
Page 87
Page 88
Page 89
Page 90
Page 91
Page 92
Page 93
Page 94
Page 95
Page 96
Page 97
Page 98
Page 99
Page 100
Page 101
Page 102
Page 103
Page 104
Page 105
Page 106
Page 107
Page 108
Page 109
Page 110
Page 111
Page 112
Page 113
Page 114
Page 115
Page 116
Page 117
Page 118
Page 119
Page 120
Page 121
Page 122
Page 123
Page 124
Page 125
Page 126
Page 127
Page 128
Page 129
Page 130
Page 131
Page 132
Page 133
Page 134
Page 135
Page 136
Page 137
Page 138
Page 139
Page 140
Page 141
Page 142
Page 143
Page 144
Page 145
Page 146
Page 147
Page 148
Page 149
Page 150
Page 151
Page 152
Page 153
Page 154
Page 155
Page 156
Page 157
Page 158
Page 159
Page 160
Page 161
Page 162
Page 163
Page 164
Page 165
Page 166
Page 167
Page 168
Page 169
Page 170
Page 171
Page 172
Page 173
Page 174
Page 175
Page 176
Page 177
Page 178
Page 179
Page 180
Page 181
Page 182
Page 183
Page 184
Page 185
Page 186
Page 187
Page 188
Page 189
Page 190
Page 191
Page 192
Page 193
Page 194
Page 195
Page 196
Page 197
Page 198
Page 199
Page 200
Page 201
Page 202
Page 203
Page 204
Page 205
Page 206
Page 207
Page 208
Page 209
Page 210
Page 211
Page 212
FACULTY OF ENGINEERING Professor of Agricultural Engineering Soil and Water Specialization Head Department of Mechanical and Manufacturing Engineering Tel 868 662 2002 ext 82170 82171 E-mail PROF. EDWIN EKWUE My main area of research is investigating the effect of organic materials on the physical and engineering properties of soils that affect soil erodibilitysoil compaction and compressibility by farm machines working on soils. The understanding of these effects and their consequent quantification has been the thrust of my research activities over the years. My research recently extended into the investigation of the role of organic materials into some other engineering properties of soils like thermal and electrical conductivity of soils. Soil erodibility refers to the vulnerability of the soil to erosion that is the soil factor in the soil erosion process. My initial PhD research focused on the role of organic materials on soil erodibil- ity. It involved the study of the effect of organic materials on all the major factors that affect soil erodibility soil detachment infiltrationsoil shear strengthsoil crust strengthsoil compaction soil aggregate stability and aggregate breakdown.It exposed the two major processes involved in the reduction of soil erodibility by organic materials stabilising soil aggregates by colloidal organic materials like grass farmyard and green manure and acting as a mulch like fibrous inert particles such as peat. The research helped to explain the different opposing relationships previously obtained by different researcherssuch as the relation- ship between soil detachment and aggregate stability. The relationship was found to be positive for fibrous organic matter and negative for the colloidal ones.Also not well understood was the effect of organic matter on soil shear strength. This was also found to depend on the type of organic materials. All organic materials were exposed as being able to reduce bulk density increase soil porosity reduce soil erodibility and increase infiltra- tion rates of the soil. My research also revealed that the type of organic material for example peat grass green manure and not just the total organic matter content was important in soil erosion research. These effects were described and quantified. The effect of soil strength on detachment was described and a model equation was developed to describe soil detachment. Lastly the study involved the development of equipment required in soil erosion research including the design and construction of rainfall simulators soil air permeameter soil penetrometer and a novel equipment for measuring infiltration rates of soils during rainfall. This PhD research led to the publica- tion of nine journal papers in the area of soil erosion research. The Journals include Journal of Arid Agriculture Nigeria Earth Surface Processes and Landforms UK Soils and Tillage Research Nether- lands and Soil TechnologyNetherlands. On my arrival at The University of the West Indies in St. Augustine Trinidad in January 1992 the methods required to boost agricultural production in the Caribbean region were reviewed with emphasis on the increased supply of irrigation infrastructure and tractors for large-scale food production.Water resources available to Caribbean countries and water demand were investigated. On the irrigation side water available for irrigation in Trinidad was found to be limited prompting research on the best use of the limited water allocated for irrigation.The level of water required to irrigate different crops in the local setting was quantified using lysimeters as well as using the empirical best model Penman-Monteith which was soon discovered. Investigation was carried out on the possible use of sewage and industrial wastewater to irrigate some local crops. Rainfall available to Caribbean countries was statistically analysed to obtain rainfall parameters required for irrigation scheduling. Irrigation scheduling using the computer-aided irrigation system models called IRSIS and CROPWAT was soon investigated and used to schedule irrigation as well as to predict the level of water needed in different farming situations in the Caribbean. The use and implication of different evaporation pan sizes for scheduling irrigation was identified in different research works. Also investigated was the effect of soil compaction on irrigation scheduling of some crops in Trinidad.It was found that the maintenance of an adequate irrigation regime in the soil would help to ameliorate the effect of soil compaction in reduc- ing plant growth.The research on irrigation and related work was published in the Journal of Agricultural Engineering Research JAER UK Tropical Agriculture Trinidad and the West Indian Journal of Engineering WIJE. The use of hydroponic and aquaponic systems of irrigation have also been investigated and further studies are required in this area. Greater use of tractors in soil cultivation in Trinidad and the Caribbean in general will result in environmental problems principally soil compaction and compressibility and so these studies of farm machinery traffic were important. Therefore methods of reducing soil compaction were sought specifically the use of organic materials in reducing soil compaction. The first part of this research involved the quantification of the impact of different compaction efforts on soil shear strength soil bulk density and soil penetration resistance which are all indices of soil compactibility. Research revealed that organic materials like farm yard manure peat filter press mud and sewage sludge can be used to ameliorate the impact of farm 70