Assessment of surface water quality of inland valleys for cropping in SW Nigeria

O S Aboyeji,O O Ogunkoya

doi:10.1007/s13201-015-0309-8

Abstract

Inland valley agro-ecosystems which are a category of wetlands have potential for sustainable crop production relative to uplands. A major challenge to their utilisation in the study area is their heterogeneity in hydrology, morphology, soil types and agro-economy. The study assessed the surface water quality of three typologies of the agro-ecosystems—amphitheatre-like valley-heads (Am), valley-side (VS), and low depression (LD)—for cropping. Surface water of six sites were sampled during the wet and dry seasons. The physicochemical properties and metal concentrations of the samples were analysed. Descriptive statistics and water quality indices were used to assess the suitability of the waters of the agro-ecosystems for cropping. Results showed that the valleys have neutral to slightly alkaline waters. Values of physicochemical parameters are generally within the acceptable range for cropping. The concentration of major cations varied across the inland valley types, but exhibited similar characteristics within each valley. The dominance of the major cations is in the order of Na > Ca > K > Mg. ANOVA results indicated that there is no significant difference in the concentration of heavy metals across the valleys (F = 2.044, p = 0.138, α = 0.05). Generally, most of the physicochemical parameters and trace metals have low concentrations and are non-toxic to plants. Values of water quality indices (sodium adsorption ratio, soluble sodium percentage, total dissolved solids and permeability index) indicated that the concentrations of minerals in waters across the valley typologies are generally within permissible limits for cropping.

Highlights

Sustainable socioeconomic development is rarely attainable without adequate development of water resources to support food production, industry, environment and other human needs
The concentration of major cations varied across the inland valley types, but exhibited similar characteristics within each valley
The result is similar to those reported by Ogunkoya and Adejuwon (1990); Jaji et al (2007) and Ayeni et al (2011) who found a mean range of 6.8–8.0, 6.9–7.9 and 6.1–8.1, respectively, in studies conducted in parts of south-western Nigeria

Summary

Introduction

Sustainable socioeconomic development is rarely attainable without adequate development of water resources to support food production, industry, environment and other human needs. A major challenge to provision of safe water for various demands is the deteriorating quality of existing water resources. With specific reference to cropping, water of appropriate quality facilitates better crop yields under optimal soil and water management conditions. A major challenge area is food insecurity partly caused by inadequate agricultural productivity (Aboyeji and Ogunkoya 2014; Ike 2012; Ogunremi et al 2000). Food production in southwest Nigeria traditionally occurs on upland ecosystems through rain-fed cultivation. The major means of sustaining soil fertility in this region is through bush-fallowing and application of fertilisers—domestic waste, animal manure and inorganic fertilisers.

Methods

Results

Conclusion