Irrigation Capability Evaluation of Illushi Floodplain, Edo State, Nigeria

Many irrigation projects, especially in the developing tropical regions, are embarked upon without any land capability assessment, resulting in avoidable and undesirable ecological consequences. The aim of this study is to assess the irrigation capability potentials of the soils of a rice growing Illushi/Ega community in Edo State of Nigeria. Soils of Illushi/Ega (200 ha) were studied to establish their irrigation capabilities. Water samples were collected from the rivers within and near the sites at the proposed points of intake structures and analyzed for salinity (ECw), permeability (SAR) and ion toxicity [Chlorine (Cl) and Boron (B)]. Gravity irrigation suitability assessment was carried out following the guidelines of the United States Bureau for Land Reclamation (USBR, 1953) and FAO (1979). Results showed that about 5.5 % of the land was non-irrigable, 11.5 % was marginally irrigable, 30.5% was moderately irrigable and 52.5 % highly irrigable.Thus about 83 % of the total land area was found to be irrigable. The results of analyses of irrigation water [ECw, SAR and Cl and B (ion toxicity) problems in water sources were 0.1 – 0.7 dS m- 1, 1.2 – 1.7, 0.6 – 1.8 cmol kg- 1 and 0.5 – 0.7 mg kg- 1] also show that there is no indication of salinity or ion toxicity problem.