Assessment and Mapping of the Vulnerability of Soils in Imo State, Nigeria to Erosion Hazard Using Geographic Information System
International Journal of Environmental Monitoring and Analysis
Volume 3, Issue 5, October 2015, Pages: 245-259
Received: Jul. 25, 2015;
Accepted: Aug. 12, 2015;
Published: Sep. 24, 2015
Views 5787 Downloads 140
Emeka Udokporo, Department of Geography and Meteorology, Enugu State University of Science and Technology, Enugu, Nigeria
Martin Atu Ngozika Anikwe, Department of Agronomy and Ecological Management, Enugu State University of Science and Technology, Enugu, Nigeria
Kevin Ejike Chukwu, Department of Geography and Meteorology, Enugu State University of Science and Technology, Enugu, Nigeria
Soil erosion by water is a critical problem in Imo State terrain due to anthropogenic pressure on its landscape. Assessment and mapping of erosion prone area is essential for soil conservation and watershed management. The objectives of the study are to use satellite imageries to assess and map the land cover, vegetation, land use, topography and hydrology; and to use field sampling to map soil properties and soil erodibility of Imo State with a view to assessing soil erosion hazard in Imo State. The DEM was generated to prepare slope map, elevation map and hill shading map. Results from the study show that 45.4 % of the land cover of Imo State representing 2256.7 Km2 is covered by light vegetation whereas 24.7 % of the land area representing 1229 Km2 is covered by thick vegetation. The result also showed that a large percentage of the entire land area (21%) representing 1046.3 Km2 is cultivated whereas 6.4% representing 319 Km2 is built up with houses and infrastructure like roads, bridges etc. The area covered by thick vegetation (24.7%) is categorized under slightly vulnerable to stable. A larger percentage (45.4%) is covered by light vegetation, and therefore, classified as moderately vulnerable to erosion whereas 27.4% comprising cultivated and built up areas are classified as highly to extremely vulnerable to erosion. Results also show that most parts of the state (4133Km2) representing 84% of the entire landscape fall into slightly to less vulnerable to erosion with a slope class between 1 – 4% slope. The results on hill shading concur with that of slope above. As expected, the dispersion ratios were affected by the type of underlying parent material. Results from the characterization of soil properties of study area show since most soils in the study area have high dispersion rates, depicting high vulnerability to soil erosion and 84% of the entire landscape fall into slightly to less vulnerable to erosion with a slope class between 1 – 4% slope, it then follows that high rates of erosion recorded for the area may be due to land use and management as light vegetation, cultivation and built areas cover 73% of the land area and classified as moderately to extremely vulnerable to erosion. The result at landscape and plot scale varies. Therefore, model results need to be carefully used for local level soil conservation planning.
Martin Atu Ngozika Anikwe,
Kevin Ejike Chukwu,
Assessment and Mapping of the Vulnerability of Soils in Imo State, Nigeria to Erosion Hazard Using Geographic Information System, International Journal of Environmental Monitoring and Analysis.
Vol. 3, No. 5,
2015, pp. 245-259.
Asiabaka, C. C., & Boers, T. M. (1988). An Analysis of existing traditional methods of Farming and Erosion Control among Farmers in South Eastern Nigeria. In Proceeding of First International Symposium on Erosion in South Eastern Nigeria (Vol. 1, No. 1, pp. 109-114).
Bakker, M. M., Govers, G., Jones, R. A., Rounsevell, M. D. A., 2007. The effect of soilErosion on Europe's crop yields. Ecosystems 10, 1209–1219.
Dane, J. H., & Hopmans, J. W. (2002). Water retention and storage. Methods of soil analysis. Part, 4, 671-717.
Egboka, B. C. E. (2004). Distress Call and Plea to the Senate Committee for Urgent Actions Against Floods, Soil/Gully Erosion/ Landslides Disasters in the Southeast. Paper Presented to Senate Committee on Environment: Roads/Erosion Senate Delegation to the Southeast. 30p.
Gee GW and Bauder JW1986 Particle size analysis. In Methods of Soil Analysis. Part I. Agronomy 9. Ed. A. Klute. pp. 383–411.Am. Soc. Agron., Madison, WI. USA.
Igbokwe, J. I., Akinyede, J. O., Dang, B., Alaga, T., Ono, M. N., Nnodu, V. C., & Anike, L. O. (2008). Mapping and monitoring of the impact of gully erosion in Southeastern Nigeria with satellite remote sensing and Geographic Information System. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 37, B8.
Istvánovics, V. 2009. Eutrophication of lakes and reservoirs, p. 157–165. In: G.E. Likens [ed.], Encyclopedia of Inland Waters, vol. 1. Elsevier, Oxford.
Kirkby, M. J., & Bracken, L. J. (2009). Gully processes and gully dynamics. Earth Surface Processes and Landforms, 34(14), 1841-1851.
Middleton, H. E. 1930. Properties of soil which influence soil erosion. U.S. Dept Agronomy Tech. Bull. 178pp.
Mulla, D. J., & McBratney, A. B. (2010). 9 Soil Spatial Variability. Soil physics companion, 343.
Nill D., Schwertmann U., Sabel-Koschella U., Berhard M. and Breuer J. 1996. Soil erosion by water in Africa. Principles, prediction & protection. GTZ, Germany. 292 pp.
Ofomata, G. E. K. (1985). Soil Erosion in Nigeria: The Views of a Geomorphologist. 7th Inaugural Lecture. University of Nigeria, Nsukka, Nigeria. pp.
Ogbonna, J. U. (2012). Understanding Gully Erosion Vulnerability in Old Imo State Using Geographic Information System and Geostatistics. American Journal of Geographic Information System, 1(3), 66-71.
Okoro, B. C., Uzoukwu, R. A., & Chimezie, N. M. (2014). River Basins of Imo State for Sustainable Water Resources Management. Journal of Civil & Environmental Engineering 4,130-138.Pimentel, D., Harvey, C., Resosudarmo, P., Sinclair, K., Kurz, D., McNair, M & Blair, R. (1998). Land use, erosion and water resources. Water resources, environmental planning, management, and development. Tata McGraw-Hill Publishing Limited, New Delhi, India, 37-71.
Shoghi, H, Ghazavi M, Kazemain, S, Moayedi H (2013) A state of the art review of dispersive soils. Identification methods perspectives. European Journal of Scientific Research107: 322-328.
Thomas, T. 1991. Aspects of soil degradation and conservation measures in Agucho catchment, West Hararghe. Soil Conservation Research Project Report 19. University of Bern, Switzerland. 125 pp.
Udo, R. K. (1970). Geographical regions of Nigeria. Univ of California Press.
Valentin, C., Poesen, J., & Li, Y. (2005). Gully erosion: impacts, factors and control. Catena, 63(2), 132-153.
Van Oost, K., Govers, G., & Desmet, P. (2000). Evaluating the effects of changes in landscape structure on soil erosion by water and tillage. Landscape ecology, 15(6), 577-589.
Wischmeier, W. H., & Smith, D. D. (1978). Predicting rainfall erosion losses-A guide to conservation planning. Predicting rainfall erosion losses-A guide to conservation planning.
Yang, D., Kanae, S., Oki, T., Koike, T., Musiake, K., 2003. Global potential soil erosion with reference to land use and climate changes. Hydrological Processes 17, 2913–2928.
Zuazo, V. H. D., & Pleguezuelo, C. R. R. (2009). Soil-erosion and runoff prevention by plant covers: a review. In Sustainable Agriculture (pp. 785-811). Springer Netherlands.