Table of Content of the Proceedings of the 1st International Symposium on Erosion in South-Eastern Nigeria

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

TABLE OF CONTENTS

  1. Ofomata, G.E.K., 1988. The Management Of Soil Erosion Problems In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of  Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/001, volume 1(1);p.3-12.

  2. Poesen, J., 1988. A Review of the Studies On The Mechanisms Of Incipient Rilling And Gullying In The Belgian Loam Region, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of  Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/034, volume 1(1);p.13-20.

  3. Egboka, B.C.E., 1988. Erosion Hazards In Southeastern Nigeria: Hydrological and Environmental Implications and Suggested Control Programmes, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/003, volume 1(1);p.21-22.

  4. O. Aneke., 1988. Case Studies Of Erosion Control Projects In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  April., 1988, Paper ISE/SEN/002, volume 1(1);p.22-23.

  5. Boers, T.M., H.O. Maduakor and D.P Tee., 1988. Sheet Erosion From A Bare Sandy Soil In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/024, volume 1(1);p.23-34.

  6. Nwachukwu, B.A., 1988. Regime Dimensions Of Natural Streams In Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/025, volume 1(1);p.35-41.

  7. Ezeigbo, H.I., 1988. Erosion And Gullying Problems In Umuahia And Environs, Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of  Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/023, volume 1(1);p.41-42.

  8. Sluiter, – W.J., 1988. Some Geomorphological Factors and Their Influence On Erosion in the Osina Basin , Southeastern, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/027, volume 1(1);p.43-46.

  9. Eppink, L.A.A.J.,1988. Research On Modern Survey Methods In Erosion Project Studies, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of  the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/027, volume 1(1);p.47-53.

  10. Ijioma, C.I., 1988. Compactive Energy For Erosion Control On Earth fill Materials At Ohafia, Imo State Of Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/032, volume 1(1);p.54-58.

  11. Chukwueze, H.O., 1988. The Contributions Of Soil Erosion To Pavement Failures In Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/032, volume 1(1);p.59.

  12. Posen, J., 1988. Surface Seal Formation And Soil Erosion Sub-processes, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/004, volume 1(1);p.60-67.

  13. Chukwuma, G.O., 1988. The Effects Of Bamboo Roots In Gully Slope Stabilization, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/004, volume 1(1);p.68

  14. Okeke, P.O., G.I, Nwankwor and G.N Nnadi .,1988. Development Of A Model For Gully Erosion For S.E Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/029, volume 1(1);p.69

  15. Nwachukwu, B.A and C.I. Ijioma., 1988. Performace Evaluation Of Civil Engineering Structures For Erosion Control In Southeastern Nigeria: Case Study, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/021, volume 1(1);p.70-75.

  16. Tee, D.P., 1988. Groundwater, Surface Runoff and Erosion: How Related?, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/010, volume 1(1);p.76-81.

  17. Ibe, K.M., S.E. Ananaba,, W.J. Sluiter., H. Krynen and B. Nwachuwku., 1988. Sampling Of Geology and Hydrology Of Chosen Sites In The Study Area – A Progress Report, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research  Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/019, volume 1(1);p.82.

  18. Boer, T.M., H.O. Maduakor and D.P. Tee., 1988. Measurements Of Rainfall, Runoff And Soil Loss On Experimental Plots For Development Of A Sheet Erosion Model, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/018, volume 1(1); p.83.

  19. Nwachukwu, B.A and A.J.C. Van De Kerk., 1988. Estimates of Drainage Basin Erosion Index From Stream Sediment Load Measurements, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th  , 1988, Paper ISE/SEN/009, volume 1(1);p.84-90.

  20. Krynen, H., 1988. A Study of Erosion (Cause and Remedies) Based On Hydrological Data, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/015, volume 1(1);p.91.

  21. Ijioma, M.A., 1988. A Conceptual Ecosystems Model For Effective Gully Erosion Management: A Case Study Of Onu Igbere Gully, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/031, volume 1(1);p.92-97.

  22. Nwankwor, , G.I. ,P.O. Okeke And E. Castenmilla., 1988. Determination And Relevance Of Parameters Of A Gully Growth Model For Okwudor – Amucha Gully Complex, Imo State, Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/033, volume 1(1);p.98.

  23. Boers, T.M., U. G. Atu., J.C. Obifuna and D.P . Tee., 1988. Aspects Of Ridging And Cropping For Gully Reclamation, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/016, volume 1(1);p.99.

  24. Maduakor, H.D., D.P. Tee., K.M. Ibe and C.I. Ijioma., 1988. Determination Of Erosion Related Parameters At Chosen Sites, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/017, volume 1(1); p.100.

  25. Olaniyan, G.O., 1988. Assessment Of Soil Erosion Under Different Seed Bed Preparation In South East Nigeria , Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/007, volume 1(1); p.101.

  26. Maduakor, H.O., 1988. Soil Physical and Chemical Properties Affecting Erodibility of Some Soils In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/008, volume 1(1); p.102-106.

  27. Obiefuna, J.C.,1988. Alterative Land Preparation Techniques as Anti-Erosion Management Strategy For Plantation Agriculture in the Tropical Rainforest, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/005, volume 1(1); p.107.

  28. Isirimah, N.O and L.C. Nwaigbo., 1988. Soil Erosion and Control Efforts In Some Parts Of Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/035, volume 1(1); p.108.

  29. Asiabaka, C.C and T.M. Boers. 1988. An Analysis Of The Existing Traditional Methods Of Farming And Erosion Control Among Farmers In Southeastern Nigeria, Proceedings of the First International Symposium on Erosion in Southeastern held at the Federal University of Technology, Owerri, Nigeria, under the auspices of the European Economic Council (EEC) Supported Erosion Research Project, Institute of Erosion Studies (IES), 11-12th, 1988, Paper ISE/SEN/036, volume 1(1); p.109-114.

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PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/001

THE MANAGEMENT OF SOIL EROSION PROBLEMS IN SOUTHEASTERN NIGERIA

OFOMATA, G.E.K

Department Of Geography, University Of  Nigeria, Nsukka.

ABSTRACT

Soil erosion occurs all over Southeastern Nigeria. As a matter of fact, it is one of the most striking features on the land surface of that part of the country. Although sheet erosion is significant, one usually thinks of gullying whenever soil erosion is mentioned in the area. This is mainly because erosion features, mostly the gullies constitute an interesting form of topography and are also a source of great concern, especially in terms of their adverse effect on the agricultural potentialities of the area. The major concern of this paper is to review some of the existing measures against soil erosion especially in their inadequacy, and attempt to consider some appropriate management strategies. Before doing this  however, it would be necessary to outline briefly the factors, types, extent and process of soil erosion in Southeastern Nigeria.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/034

A REVIEW OF THE STUDIES ON THE MECHANISMS OF INCIPIENT RILLING AND GULLYING IN THE BELGIAN LOAM REGION

J. POESEN

Research Associate, National Fund for Scientific Research , Laboratory of Experimental Geomorphology, K.U. Leuven, Redingenstraat 16 bis, B-3000 Leuven, Belgium

 

ABSTRACT

Rill and gully erosion account for 60 to 80% of total sediment produced in the Belgian Loam Region. A summary of recent research results obtained at the Laboratory of Experimental Geomorphology is presented, elucidating some factors controlling rill and gully formation. Conditions for rill genesis can be described by the ratio between overland flow, shear stresses and top soil shear strength. The influences of soil shear strength, soil texture and soil water content on these conditions are discussed. Finally, the role of the biological factor in both rill and gully formation is described.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/003

EROSION HAZARDS IN SOUTHEASTERN NIGERIA: HYDROLOGICAL AND ENVIRONMENTAL IMPLICATIONS AND SUGGESTED CONTROL PROGRAMMES

B.C.E. Egboka

Special Project/Research Unit Anambra State University of Technology, Awka Campus ,P.M.B 5025, Awka, Nigeria.

ABSTRACT

Parts of Southeastern Nigeria (Benue, Anambra, Imo, Akwa-Ibom and Cross River States) are ravaged by soil and gully erosion and landslides. Lives and property have been lost. The genesis of the hazards are rooted in the environmental factors of rainfall, geomorphic and pedologic features, peculiar nature of the north south trending escarpments, geological, geotechnical and hydrogeological characteristics, and anthropogenic activities. The erosional  processes are complex, dynamic, continuous and regional in nature, making control programmes difficult and unsuccessful. This is further complicated by erosional problems and dynamics being poorly-understood. Experts from different disciplines involved in erosion investigations and control misunderstand themselves. Geologists, pedologists, agriculturists, foresters, engineers, differ widely in suggestions proffered. This has exacerbated the erosion problems. Sheet, rill, channel / bank and gully erosion and landslides in Southeastern Nigeria demand a multidisciplinary, multi-objective, multi-technique and integrated approach in both investigations and control. The Local, State and Federal Governments and higher institutions must be involved in coordinated efforts to combat these endemic hazards. An Environmental Hazard Monitoring Centre (EHMC) for southeastern Nigeria must be established. The EHMC shall monitor the quasi-stable environment on a continuous basis in order to predict potential hazards and suggest urgent contingency measures.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/002

CASE STUDIES OF EROSION CONTROL PROJECTS IN SOUTHEASTERN NIGERIA

D.O ANEKE

Department of Agricultural Engineering, University of Jos, Makurdi Campus, Makurdi

 

ABSTRACT

The history and factors of gully erosion control in Southeastern Nigeria are briefly stated. Case studies of erosion projects in the region is the main topic discussed. Although natural forces cause erosion, the single most important agent of erosion is man. This takes place when he carelessly inflicts his activities on land. Consequently, expensive corrective measures have to be taken to safeguard life and property. Appropriate corrective measures cannot be effectively adopted if the hydraulic processes and the underlying science of erosion is not well understood. Such corrective measures and the hydraulic processes of erosion phenomenon are therefore discussed in this paper. The highlights of this paper are the new dimensions in soil erosion phenomenon and the recommendations for effective control programme in the states.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/024

SHEET EROSION FROM A BARA SANDY SOIL IN SOUTHEASTERN NIGERIA

BOERS, T.M., H.O MADUAKOR AND D.P TEE

Federal University of Technology Owerri, Nigeria

ABSTRACT

The changes in water and soil balances caused by the removal of tropical rain forest, which exposes the soil to erosive rainfall are discussed in this paper . Sheet erosion from bare soil was measured on runoff plots of 22 x 4m2 each, located on a slope of loamy sand. Three surface treatments were investigated: bare smooth soil without ridges, bare soil with ridges down the slope and bare soil will contour ridges. The effect of raindrop impact on bare soil was evaluated. Measurements of dry bulk density and infiltration rate were taken to estimate top soil compaction and crust formation during the rainy season of 1987. Measurement of rainfall, runoff and soil loss indicate a very high erosion intensity in tons of soil loss per ha per year. Infiltration rates measured with the double ring infiltrometer are discussed, and it is concluded that these measurements are not relevant for erosion research. An alternative method to evaluate infiltration rates from rainfall runoff events is considered and applied.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/025

REGIME DIMENSIONS ON NATURAL STREAMS IN IMO STATE, NIGERIA

B.A. NWACHUKWU

School of Engineering,  Federal University of Technology, Owerri.

ABSTRACT

Channels formed in alluvial or other grannular materials are said to be in-regime if their geometry remains substantially unchanged by scour or sediment deposition. This however does not preclude minor channel erosion or accretion during yearly cycle of flow but it does require that opposing effects should cancel out on an annual basis. The regime concept was initially formulated on the experience gained from canal systems but since the concept is based on the theory of channel self adjustment, it has been found applicable both for unlined canals and natural streams. It is now acceptable practice to design stable canal systems from a set of regime equations determined from natural streams in the locality of the work. In this paper, a set of regime equations determined from a survey of natural streams in Imo State is presented. The equations are compared with the regime equations developed for some other countries. It is found that the present set of equations conform to those other equations with some difference only in the coefficients. The new set of equations is proposed for the design of non-erodible channels in Imo State and it is suggested that the study be extended to other states in South Eastern Nigeria to determine if the equations are consistent for this larger geographical area.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/023

EROSION AND GULLYING PROBLEMS IN UMUAHIA AND ENVIRONS

H.I. EZEIGBO

Department of Geology University of  Nigeria, Nsukka.

ABSTRACT

Field studies of erosion and gullying sites in Umuahia and environs were carried out in over 200km2 of territory. The affected geological formations are mainly the Ameki Formation and the Ogwashi-Asaba Formation even though some significant gullying occurs within the younger Benin Formation outcrops to the south. Within the Umuahia urban, poorly constructed and / or inadequate drainage channels expose the loose soils to erosion and gullying by the usually intense rains of the area. Within the rural areas, deforestation is a major causative factor. The densely populated rural areas rely mainly on wood for energy, and bush burning remains a favoured agricultural practice. Little or no consideration is made for drainage channels in the “development” roads build in the rural areas. Both the Ogwashi-Asaba and Benin Formations have clay intercalations that furnish easy sliding surfaces when wetted by infiltrating rain water. Several measures have been recommended for controlling the gullying menace which includes water channelization efforts, planned agricultural practices, public education on alternative energy sources as well as some legislation.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/027

SOME GEOMORPHOLOGICAL FACTORS AND THEIR INFLUENCE ON EROSION IN THE OSINA BASIN, SOUTHEASTERN NIGERIA

W.J. SLUITER

Federal University of Technology,  Owerri.

ABSTRACT

The present study, executed in a part of the Imo river basin, Nigeria, shows the possibility of making a slope map and a surface run-off map utilizing a topographic map. The slope as well as the surface run-off has a direct relation to erosion intensity.   The above mentioned maps have been prepared as a contribution to the compilation of an erosion hazard map, an essential tool for the control of erosion in the Imo River Basin.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/038

RESEARCH ON MODERN SURVEY METHODS IN EROSION PROJECT STUDIES 

(A review of an Erosion Research Programme of the Wageningen Agriculture University)

EPINK, L.A.A.J

ABSTRACT

At the Agricultural University at Wageningen, several Departments provide for teaching and research on soil erosion. An integration of the different aspects is obtained in Erosion Study Projects which are carried out in Spain. The overall goal is the formulation, elaboration and evaluation of alternative soil and water conservation plans for a specific watershed or sub-watershed, which are technically effective, economically feasible and socially acceptable. During the planning process, much information, obtained from maps, documents, photogrammetry, airphoto-interpretation, field observations, measurements and inquires have to be used in different combinations. In order to study the possibilities of the use of advanced survey methods in the field, a methodological study is being carried out. Because such a study needs a continuous checking of partial results with field conditions, a small pilot area near Wegeningen has been selected. Simultaneously, two other projects are going on. In cooperation with the University of Utrecht, a small watershed near Catsop in the hilly Southern part of the Netherlands is being surveyed and monitored and the ANSWERS simulation model is being tested out. Some results will be presented. Another project study in Spain serves as a teaching project for our students. In that project, the findings of the former programmes are tested on practical applicability.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/032

COMPACTIVE ENERGY FOR EROSION CONTROL ON EARTHFILL MATERIALS AT OHAFIA,

IMO STATE OF NEIRGIA

C.I. IJIOMA

School of Engineering and Engineering Technology, Federal University of Technology Owerri.

ABSTRACT

Some serious soil erosion sites in Imo State have been associated with the disturbance of soil during and after major civil engineering works. Some of these works include: land grading, urban roads, dams and inter-city roads, all of which involve compaction to maximum density. Unfortunately, the compactive energies employed to achieve a certain maximum dry density have never been related to the resulting dispersive characteristics of the disturbed compacted soil. The erodibility of these earth fill materials has adversely given rise to different forms of erosion. A method is being developed to relate the compactive energies into the electrical conductance of the water passing through a pin hole in a compacted lateritic soil. The test has been carried out on soil samples from Ohafia in Imo State.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/028

THE CONTRIBUTIONS OF SOIL EROSION TO PAVEMENT FAILURES IN NIGERIA

H.O CHUKWUEZE

Department of Civil Engineering, University of Nigeria, Nsukka.

 ABSTRACT

The paper examines the role of soil erosion in the progressive destruction of many paved roads in Anambra State and suggests how the phenomenon may be checked. Some field work was conducted which revealed that the failure of the road pavement may start from the road shoulder which is composed of uncompacted materials usually sand with clay. The removal of the shoulder materials exposes the pavement structure which is usually stratified and so is selectively eroded thereby destabilizing the superjacent layers which then cave in. The destruction of the pavement at the culverts begins with the understand-scouring of the culvert chamber composed of units of segmented concrete casts. The units break off at the joints under the resultant moments. In either of the two cases observed, the road pavement fails in a progressive manner as the erosion element eats its way across the pavement structure. It is shown that the removal of the road pavement shoulder materials by the flowing rain water may be minimized if carefully blended well graded sand-gravel mixture is used. Also the collapse of the shoulder could be prevented at culverts if monolithically cast concrete culvert chamber rather than the segmented ones are used. The improved methods need not increase the initial costs and will certainly reduce the maintenance costs of the pavement. These measures added with expert advice especially of the soil engineers should reduce or stop the phenomenon.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/004

SURFACE SEAL FORMATION AND SOIL EROSION SUB-PROCESSES

J. POSEN

Research Associate , National Fund for Scientific Research, laboratory of Experimental Geomorphology, K.U. Leuven, Redingenstraat 16 bis ,B -3000 Leuven ,Belgium.

ABSTRACT

Surface sealing is an important process of physical soil degradation in Southeastern Nigeria. Therefore, a summary of recent research results obtained at the Laboratory of Experimental Geomorphology is presented in order to elucidate some factors controlling seal formation as well as the interactions between surface sealing and soil erosion sub-processes. Sandy soils containing 80 to 95% sand and 20 to 5% silt and / or clay have been found to be extremely susceptible to surface sealing. Topographic parameters such as slope gradient and length have negative effect on sealing intensity. This is explained by the fact that erosion rate largely controls seal development. On the other hand, surface seal formation determines  in an ambivalent way, the  rate  at which several soil erosion sub processes by water operate: surface sealing decreases the intensity of inter-rill erosion sub processes but increases the runoff volume and hence, the potential for rill and gully erosion.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/029

THE EFFECTS OF BAMBOO ROOTS IN GULLY SLOPE STABILIZATION

G.O. CHUWKUMA

Department of Agricultural Engineering, University of Nigeria , Nsukka.

ABSTRACT

Bamboo (Bambusa vulgaris) is widely used in gully slope stabilization but there is no documented evidence of the effectiveness of bamboo roots in reinforcing the soil mass against shear failure. The study explores the engineering properties of soil samples taken from beside a bamboo stand used in gully erosion control and compares the result with those obtained from soil samples taken at distance from the bamboo stand but within the same soil type. The results of the study will be useful in developing technical guide for recommending bamboo as a vegetative soil erosion control measure for varying gully slopes.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/002

DEVELOPMENT OF A MODEL FOR GULLY EROSION FOR SOUTHEASTERN NIEGRIA,

P.O OKEKE., G.I, NWANKWOR AND G.N NNADI

Federal University of Technology, Owerri.

ABSTRACT

Erosion studies of south-eastern Nigeria are being implemented under the EEC/FUT, Owerri Linkage. One of the sub-themes of these studies is a development of a model for gully erosion for south-eastern Nigeria. The authors of this report are members of this sub-theme. The phase 1 of the sub-theme involves the determination of the geometric characteristics, such as the thickness of erodable materials and the real extent of the watershed using either seismic survey or vertical Electrical Soundings (VES) over selected areas  within  south-eastern Nigeria. It is possible that through these geophysical investigations (depending on the penetration or probe depth), geologic discontinuities – cavities, joints, fractures and faults which cause gully erosion will be mapped. Although these discontinuities are not explicitly represented in the model equation, any knowledge about their presence will influence the evaluation of model behavior. Three sites which have been known to be classic ongoing erosion sites in the south – eastern Nigeria – Okwudo, Amucha and Osina were chosen for the Phase 1 investigation. The Federal Surveys map of Nigeria of 1967 (sheet 312-Okigwe), clearly shows the nature of gullies in these sites.  Four soundings were done, using the Schlumberger configuration.  All results were interpreted with an IBM Computer. All studies were done in March 1987.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/021

PERFORMANCE EVALUATION OF CIVIL ENGINEERING STRUCTURES FOR EROSION CONTROL IN SOUTHEASTERN NIGERIA – CASE STUDY

B.A NWACHUKWU AND C.I. IJIOMA

School of Engineering and Engineering Technology, Federal University of Technology, Owerri

ABSTRACT

Erosion control can be achieved by both structural and non-structural measures. In the main, the structural measures are applied to gully erosion and stream bank erosion; non-structural measures for erosion control are mostly applicable to sheet erosions. Gully erosion is mostly as a result of flow concentration from civil engineering works or drainage basin modification, and bank erosion results from high stream velocities. The objectives of  the research team centered on the appraisal of  the performance of  in-place structures used to prevent gully and stream bank erosions in selected locations in Southeastern Nigeria. The studies so far completed included the bank erosion of  Ekuku River near Enugu Airport in Anambra  State and the geotechnical investigation of the gully erosion control works in Abiriba and Ohafia in Arochukwu/Ohafia Local Government Area in Imo State.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/010

GROUNDWATER, SURFACE RUNOFF AND EROSION: HOW RELATED?

D.P. TEE

Department of Civil Engineering, Federal University of Technology Owerri.

ABSTRACT

The paper describes a study undertaken at Amucha, Imo State, one of the serious erosion sites in the Southeastern states of Nigeria. The study concentrates on the relationship between groundwater, surface runoff and erosion. Field observation and various measurements strongly confirm that soil erosion results from a combination of  various forces including groundwater. Groundwater extruding through various weak points along the stream channel down slope results in undercuts, causes a reduction in granular pressure and provides for increased erodibility by surface runoff. The stream channel was seen as a groundwater drain or a point of discharge for excess groundwater from infiltrated rainwater. The study revealed that the excess of the initially low groundwater discharge capacity by precipitation surplus resulted in an enlargement of the groundwater discharge area and that upward seepage and out flowing of groundwater weakened the cohesive force of the soil thereby encouraging the sliding of the overburden materials.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/018

MEASUREMENT OF RAINFALL, RUNOFF AND SOIL LOSS ON EXPERIMENTAL PLOTS FOR DEVELOPMENT OF A SHEET EROSION MODEL

BOER, T.M.,  H.O. MADUAKOR AND D.P TEE

Federal University of Technology,  Owerri.

ABSTRACT

This paper reports on progress made in subtheme number 3 of the EEC Erosion Research Project during the period April  1986  to  April 1988. The data obtained during the year 1987 are suitable for the use of a simple hydrological model based on daily measurements of rainfall, runoff and soil loss. Continued measurements, which should include accurate hydrogen recording, will allow the development of a more advanced model based on the kinematic wave equation. The paper discusses experimental work completed on 6 runoff plots with 3 different surface treatments: smooth surface no ridges, ridges down the slope and ridges across the slope. All details regarding materials and methods, collected data and discussion of results are reported in a technical paper written for the International Symposium on Soil Erosion in South Eastern Nigeria. Some problems encountered in the research are discussed and the paper further outlines future directions for research followed by concluding remarks.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/009

ESTIMATES OF DRAINAGE BASIN EROSION INDEX FROM STREAM SEDIMENT LOAD MEASUREMENTS

B.A NWACHUWKU AND A.J.C. VAN DE KERK

Federal University of Technology, Owerri.

ABSTRACT

Soil loss or erosion in a drainage basin is affected by the processes of particle detachment by rain drops, entrainment at competent velocity of the surface runoff and sediment transport. The transported materials may be carried into the stream channel where it moves thereafter with the stream-flow as either bed load, suspended load or wash load depending on the flow and particle characteristics. The amount or rate of erosion in the drainage basin may therefore be estimated from sediment transport measurements in the receiving stream and the accuracy of this estimate would depend on the delivery efficiency of sediment from the basin to the channel. In general however, the accuracy of the estimates would increase when averaged over a long period of measurements. In the study reported  here, the erosion rates of two drainage basins in Imo State are determined from stream sediment transport measurements. To obtain the estimates, water level recorders were installed in the streams and rating curves were established by discharge measurements at various stages. Also from simultaneous measurements of discharge and suspended sediment load, the sediment rating curves for the streams were equally established. The sediment yields of the basins were estimated by relating both the stage-discharge curve and the sediment rating curve with the stage hydrograph over the period of available data. The erosion rates for the two basins were estimated as 3600 and 23,100 tonnes per annum respectively. The factors responsible for the observed low rate of erosion for the two basins are discussed.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/015

A STUDY OF EROSION (CAUSES AND REMEDIES) BASED ON HYDROLOGICAL DATA

KRYNEN, H.

Federal University of Technology, Owerri.

ABSTRACT

The study is based on data collected in subtheme 4 concerning hydrology. Furthermore, data were obtained from the meteorological service, from Imo River Basin Authority and Techno Synesis. After an introduction and description of the different forms of erosion,  the paper concentrates on hydrological analysis. The analysis consists of rainfall analysis – infiltration analysis- determination of runoff and sediment yield. The risqué of erosion and the control measures are related to the slopes and landuse. Therefore the first approach to erosion must be correct landuse based on land classification. Basically there are two types of mechanical protection works. Drainage and storage realization of a drainage system will be very costly and therefore temporary storage is preferred. For farmland in flat areas hardly any measures are needed. For farmland on slopes, temporary storage can be affected by applying tillage with ridges within contourbunds. Along roads, infiltration pits should be constructed and in areas with houses the solution to avoid runoff will be water harvesting.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/015

A CONCEPTUAL ECOSYSTEMS MODEL FOR EFFECTIVE GULLY EROSION MANAGEMENT:

A CASE STUDY OF ONU IGBERE GULLY

M.A. IJIOMA

School of Environmental Studies, College of  Engineering and Environmental Studies, Imo State University, Okigwe.

ABSTRACT

Gully erosion is a characteristic feature on the soft sediments of the gently exposed plains, characterized by semi-consolidated soils, found widely in various parts of the Eastern States. Over this region, the total annual rainfall is high and the intensity is also high. The gully site at Onu Igbere in Bende L.G.A (Imo State) is used as a case study to describe the morpho-dynamic processes influencing gully formation in development in an erosion system to bring to sharper focus gully development in any endangered watershed. Most importantly, the present paper validates the application of a conceptual ecosystems model in ensuring an effective gully erosion control in any watershed in Nigeria in general and in the Eastern States in particular. The ecosystems model proposed here has two main stages – the planning and design stage and the implementation and evaluation stage. The elements in the model include the energy flow transformation, the purpose for such transformation, the design to be undertaken, the professional expertise needed, the academic disciplines involved and the expected results.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/033

DETERMINATION AND RELVENACE OF PARAMETERS OF A GULLY GROWTH MODEL FOR OKWUDOR – AMUCHA GULLY COMPLEX, IMO STATE, NIGERIA

G.I. NWANKWOR, P.O. OKEKE AND E. CASTENMILLA

Department of Geology, Federal University of Technology Owerri.

 

ABSTRACT

The governing principles of a model that can be used to predict gully growth and appraise the effectiveness of various control schemes in the Amucha-Okwudor gully are posed. The envisaged model is based on a relationship between a dependent variable (gully growth rate) and a set of independent variables (factors affecting this growth). Five independent variables are considered and include soil strength (measured as clay content), rainfall, slope, watershed geometry and thickness of erodible material. The measured clay content of server soil samples in the study area range from 0.02% to 1.8%.The samples have porosity values of between 0.3 and 0.47, and an average void ratio of 0.6. The thickness of the erodible material was estimated as 30m using geophysical methods. The slope of   the approach channels range from about 80 near the uplands to over 300 near the valley walls. Other factors that affect soil strength such as groundwater seepage forces were also investigated. Preliminary calculations that were made using realistic rainfall values and representative values of the other independent variables yielded an average lateral gully growth rate of about 25m/yr. This rate is comparable to those that have need measured for other gully thus probably suggesting the appropriateness of the proposed model.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/016

ASPECTS OF RIDGING AND CROPPING FOR GULLY RECLAMATION

BOERS,T.M.,  U.G. ATU.,  J.C. OBIFUNA AND D.P . TEE

Federal University of Technology, Owerri, Nigeria

ABSTRACT

This paper reports on progress made in subtheme 1 of the EEC Erosion Research Project during the period August 1986 to April 1988. The history of a gully which developed in a slope at the campus of the Federal University of Technology Owerri is briefly discussed. Civil engineering measures were taken to cut off the upstream catchment area, close the gully with bulldozers and construct contour bunds to divide the slope in sections. Subsequent agricultural development of the area had not been completed which continued the threat of renewed gully formation. An  experimental field was established on the 2 ha slope where field trials were set up of ridging and cropping to develop proper methods to complete the gully reclamation process. The paper specifies selected cropping patterns for different sections of the field and problems encountered in the research are discussed. Future directions for research are outlined and some concluding remarks and recommendations are made.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/007

ASSESSMENT OF SOIL EROSION UNDER DIFFERENT SEED BED PREPARATION IN SOUTHEAST NIGERIA

OLANIYAN, G.O

NCRI, Badeggi

ABSTRACT

Under clean clearing and land preparation, the land is exposed for some time after sowing before crop vegetation cover. It is during this period that soil erosion is rapid under the humid climate. Therefore, this paper presents the report of work carried out in Southeastern Nigeria on soil erosion under different cultivation methods. The experiment was sited at Amakama, near Umuahia (Lat. 5.50 N, Long. 7.50 E) in the lowland rain forest zone. The area was manually cleared from secondary forest and put under cultivation in 1977 using different tillage methods of burn and plough; no burn and plough; burn and no-plough and no-burn and no plough laid out in a randomized block design with three replications. Plot size was 10 x 20m, and in 1983, runoff plots of 1m x 1m were installed in all the treatments. Eroded soil and runoff were channeled into calibrated collecting bucket provided at the lower end of each runoff plot. Each morning after it had rained the previous day, the volume of eroded soil plus run-off was read on the calibrated wall of each bucket and the water drained off allowing the sludge to settle out. The sludge was then transferred into a drying tray, dried in the oven and weighed. From twelve days after planting, soil loss was significantly higher in all ploughed plots (burning 1.92t/ha; no burn 1.79t/ha) than in no tillage plots of burn at 1.45t/ha and no burn at 1.28t/ha. It was also noticed that between six and eight weeks after planting, at about the time of second weeding and immediately after weeding, soil erosion was again significantly higher under all the ploughed treatments. The implication of these findings for soil and crop management in the region is discussed.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/008

SOIL PHYSICAL AND CHEMICAL PROPERTIES AFFECTING ERODIBILITY OF SOME SOILS IN SOUTHEASTERN NIGERIA

H.O. MADUKAOR

School of Agric and Agricultural Technology,  Federal University of Technology Owerri.

ABSTRACT

Some physical and chemical properties of soils collected from 2 transects in Southeastern Nigeria were correlated with the index of erodibility which in this study is the member of water drops (DRP) that shattered soil aggregates within 2 – 3 gm range. The index correlated positively with depth (D), bulk density (BD), fine sand (FS), clay (CL), organic carbon (OC), crystalline iron oxide (Fe l) , amorphous iron oxide (Fe 2), amorphous aluminum oxide (A1 2 ) and crystalline aluminium oxide (Al l). It correlated negatively with coarse sand (CS), penetrometer resistance (PR) and pH. The regression equation determined using the step-down method of selecting the relevant variables is given as DRP = 52.82 + 9.13  AL 2  +  18. 16 BD- 0.18 D – 99.97 Fe 2 + 2.67 PR + 7.52 Fe 1 – 0.84CS; Where DRP, AL 2, BD, D, Fe2, PR, Fe 1, and CS are as explained above.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/005

ALTERATIVE LAND PREPARATION TECHNIQUES AS ANTI-EROSION MANAGEMENT STRATEGY FOR PLANTATION AGRICULTURE IN THE TROPICAL RAINFOREST.

J.C. OBIEFUNA

School of Agriculture and Agricultural Technology,  Federal University of Technology , P.M.B 1526,Owerri Nigeria.

ABSTRACT

The experiment investigated the effect of alternative land preparation techniques on the development of sheet and gully erosion on newly established citrus orchard in the tropical rainforest of Western Nigeria. The fields were 50m wide and 300m long on 12% slope. Land preparation included bulldoze, bulldoze + plough, bulldoze + plough + harrow, slash + fell, slash + fell + burn and slash + fell + burn + manual stumping . Graduated 50cm spikes were located at 20m intervals in each plot along the slope and monthly mean values calculated. Generally, sheet and gully erosion were highest in the upper and mid reaches of  harrowed, ploughed bulldozed but least in un burnt fields. Once the gully erosion developed, initial lateral expansion was rapid but subsequently increased gradually by caving – in following progressive deepening and cutting back into the upper reaches of the developing gully. The total soil losses from the upper and mid reaches were apparently greater than sedimentation at the lower reaches. The implications on formulating anti-erosion measures prior to crop canopy cover in high rainfall areas were suggested.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/035

SOIL EROSION AND CONTROL EFFORTS IN SOME PARTS OF SOUTHEASTERN NIGERIA

ISIRIMAH, N.O AND L.C. NWAIGBO

Department of Crop / Soil Science and Forestry, River State University of Science and Technology, Port Harcourt.

ABSTRACT

Soil erosion causing factors and control measures in Southeastern Nigeria, dating back to 1982 were reviewed. Only eight out of the many identifiable serious gully erosion affected sites are described and assessed. Highway construction plus the fragile nature of the soils in the regions are known major causes for the serious gully erosion. Preservation of vegetation and forest cover remain the cheapest means of stabilizing eroded sites. This paper suggests an integrated approach to soil erosion control which should involve soil scientist, foresters, engineers and socio-economists. Erosion control work should be a continued programme rather than a crisis management measure usually taken for areas that are threatened.

PROCEEDINGS OF THE 1ST  INTERNATIONAL SYMPOSIUM ON EROSION IN SOUTHEASTERN NIGERIA HELD AT THE FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, UNDER THE AUSPICES OF  THE EUROPEAN ECONOMIC COUNCIL (EEC) SUPPORTED EROSION RESEARCH PROJECT, INSTITUTE OF EROSION STUDIES (IES), 11-12TH APRIL, 1988.

ISE/SEN/036

AN ANALYSIS OF THE EXISTING TRADITIONAL METHODS OF FARMING AND EROSION CONTROL AMONG FARMERS IN SOUTHEASTERN  NIGERIA

ASIABAKA, C.C

School of Agriculture and Agricultural Technology,  Federal University of Technology , Owerri Nigeria.

AND

T. M. BOERS.

Wegeningen Agricultural University, the Netherlands.

 

ABSTRACT

The major objective of the study was to determine the existing traditional methods of farming and erosion control in selected areas of S.E. Nigeria. Six communities: Okwudor, Amucha, Amaigbo, Isiekenesi, Ihitenansa and Obibi-Ochasi were selected because they were heavily affected by gully erosion. From these communities a random sample of 130 farmers was selected and given instruments to complete. This survey instrument asked questions relating to their socio-economic status, problems confronting them, methods of planting and their traditional methods of erosion control. The results showed that about 28% of the farmers did not attend school at all. Only 13% completed secondary education. Findings also show, that most farmers planted on mounds and beds. Only very few planted on ridges. The traditional methods of erosion control used by farmers were mixed cropping, shifting cultivation, three planting (bamboo) and digging cross bars. The farmers in the study perceived declining yields, destruction of farmland and houses as the most serious problems of erosion. Data analysis revealed that the most appropriate method of dissemination of erosion control information is through the extension agents. Other methods included radio, other farmers, television and film shows. Most farmers (68%) felt that government action is the major solution to the erosion menace.