A review of the influence of irrigation water on the selected physical and chemical properties of wetland soils of northern Nigeria

Abstract

Wetlands are soils subjected to excessive wetness, to the extent that the wet conditions influence the possible land uses. To some  extent, irrigation water is rampantly being applied on these wetlands without observing and considered the possible short and long-term effects on the soil. This paper provides a review on the influence of irrigation water on the physical and chemical properties of wetland soils. It is evident that most of these wetlands are of high importance to food security and sustainability which are however, influenced by the application of irrigation water. However, it has been reported that decrease in soil pH as a result of continuous build-up of salts due to poor soil management, fertilizer application and poor irrigation water quality has adversely affected the soil surface. The presence of exchangeable Ca, Mg and Na as carbonates influence hydroxyl ions over hydrogen ions in the soil solution therefore making the soil alkaline. The continuous intensive cropping without addition of organic matter and crop residues has rendered the
irrigated areas low of organic carbon when compared to non-irrigated areas. Moreover, due to poor seasonal drainage taking place in wetlands, the rate of OM decomposition and mineralization reduces in the soils. Nonetheless, the influence of irrigation water on the physical and chemical properties of the wetlands differs among wetlands, and even within the same wetlands. In conclusion, most of the wetlands were neither saline nor sodic but if not properly manage, could lead to build-up of exchangeable bases.

Keywords: Wetland soils, physico-chemical properties, calcium carbonates, organic carbon, crop residues and irrigation water