Land Suitability Evaluation for Soils of Rabah Floodplain, Sokoto State Using GIS Based Technology for Irrigated Rice Production

Abstract

In the face of a growing human population, there is decline in rice yield in the Sokoto floodplains reportedly due to soil fertility disturbance. For sustainable livelihoods and food security, information on land quality of the area is of importance. Thus, land suitability assessment was conducted in this study. A fixed grid pattern was set out to cover the site, and using a hand-held GPS receiver, auger observations were made at every 100m interval, following which soil boundary were demarcated. For each soil identified, two standard profiles were sunk to 2m (except where impenetrable layer or water table was encountered) and studied. Soil samples were collected from each genetic horizon, bagged and taken to the laboratory for processing and analysis. Soil properties were interpolated within the ArcGIS 10.2.2 software using the Inverse Distance Weighted (IDW) technique. About 84% of the area has nutrient availability index (NAI) of S1 and S2, due largely to suspected fertilizer application. Areas of high NAI (S1) are those largely of high suitability (S1) in the input nutrients in the order of K>N>P>Zn. Soil Quality Index (SQI) is largely of medium to low quality as most of the factors are largely characterised by S2 and S3 ratings. Percentage coverage of suitability is in the order of: S2 (44.70%) > S3 (31%) > S1 (24.30%). The area is more endowed in NAI than in SQI, and therefore of moderate suitability for rice production. Thus, farmers should adopt measures that can improve soil texture, soil water retention andboost soil organic matter.