Vulnerability of Soil Erosion in Okitipupa Area of Ondo State, Southwest Nigeria: A Climatic Problem

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Author(s) Obasi, R. A
Pages 326-335
Volume 2
Issue 4
Date April, 2013
Keywords Atterberg test, dry farming, particle size, permeability, vulnerability.
Abstract

Soil erosion is a natural phenomenon caused by a multidimensional factor. The soil vulnerability to erosion in Okitipupa area is studied with focus on climate and geotechnical characteristics as causatives. Rainfall and to a lesser extent temperature facilitate weathering, runoffs, flooding and erosion of any soil. Rainfall and temperature data of Ondo State were used for Okitipupa area since the latter is under the same climatic coverage. These data were grouped into decades for purposes of trend analyses. The results suggest that in the last three and half decades (1971-1980, 1981- 1990, 1991-2000, and 2001- 2007) the rainfall has been on the increase, an indication to show a change in the climate. The unusual increase in the trend of rainfall over time is attributable to the cause of flooding and erosion in Okitipupa area. Fifteen (15) soil samples subjected to atterberg tests ,particle size analysis, and permeability show the liquid limits of 18.3 to 44.3%, moisture content of 5.5-16.6% , fine- medium grained sand of 68.7% -96.2 and a low permeability respectively. These characteristics coupled with the increase in the trend of rainfall are suggested attributes that can make the soil vulnerable to runoffs, flooding and erosion. Dry season farming is suggested for those areas with high percentage of fine- medium grained sand. Government should discourage the construction of civil infrastructures along the coastal terrain of Okitipupa area.

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