Ecological Impact of Changing Rainfall Pattern, Soil Processes and Environmental Pollution in the Nigerian Sudan and Northern Guinea Savanna Agro-ecological Zones

Abstract

Understanding the changing rainfall pattern in northern Nigeria and its effects on soil processes and the environment is of critical importance in the assessment and management of a given ecology. Although a general decrease in annual rainfall since the late 1960s that continued into the new millenium has been observed in this zone, rainfall intensities have increased generally over the past 43 years. Correlation coefficients of monthly average rainfall with annual rainfall showed significant (P 0.05) correlation between the declines in the annual rainfall with decreased rainfall in September. Changes in rainfall intensities and spread increases the probability of increased nutrient losses due to excessive leaching with resultant groundwater pollution and water logging, which aggravates vulnerability and propensity to rapid soil degradation in the Sudan savanna. In the northern Guinea savanna, the tendency for soil wash and large-scale soil erosion becomes imminent. While little or nothing can be done concerning the changes observed in rainfall pattern, several options could be considered for reducing its negative impacts on the environment. Ecological anti-erosion techniques based on indigenous and innovative technologies are suggested to reduce the negative impacts of changing rainfall pattern on the environment and also take advantage of excess water along with its dissolved nutrients and carbon deposits for sustainable environmental management. Key words: Rainfall pattern, soil processes, environmental pollution, savanna, sustainable environmental management. Nigerian Journal of Soil Research Vol.5 2004: 23-31