Effect of irrigation on some chemical properties of fluvisols in Sudan Savanna zone of Nigeria

Soil studies were conducted to assess the effect of irrigation on exchangeable bases and cation exchange capacity in Sudan savanna zone of Nigeria. Accordingly, soil and irrigation water samples were collected from selected locations and analyzed for soil and irrigation water quality indicators using standard laboratory procedures while appropriate statistical analysis were carried out. The result of the study indicated that soils were non-saline (EC = 0.05 to 0.15 dS/m). The exchangeable Mg (1.28 to 2.23 cmol/kg) in the irrigated soils was high. No significant difference was observed between the irrigated and non-irrigated soils. The irrigation water was moderately acidic (pH 5.6 to 6.0) to slightly alkaline (pH 7.3 to 7.8) and nonsaline and non-sodic with low EC (0.21 to 0.26 dS/m), Ca (10.47 to 29.77 mg/l), Mg (3.28 to 6.32 mg/l), K (1.27 to 10.55 mg/l) and Na (0.83 to 1.33 mg/l), total dissolved solids (88.1 to 92.70 mg/l) and SAR (0.28 to 0.39) were very low in the irrigation water. The irrigated soils were more alkaline than the non-irrigated soils. It is recommended that low soil fertility should be improved through incorporation of organic materials in the study area. Key Words: Irrigation, Chemical Properties, Fluvisols, Sudan Savann

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

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 theirrigated 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 wate