Profile distribution of some physical and chemical properties of <i>Fadama</i> soils along a toposequence in the Rima Valley Sokoto, Nigeria

Abstract

Fadama (low land area) soils are usually seen as prime soils in the semi arid and arid areas of the world. The study was conducted along a toposequence south of the Rima River in Sokoto, to investigate some physical and chemical properties of the soils as they occur and how they vary along the toposequence. Results show that pH was slightly
acid to neutral (6.6-7.4), electrical conductivity high (0.8-2.0 ms/cm), organic carbon was low (1.5 gkg-1) translating to low organic matter (<20 gkg-1). The soil structure indicators fall below critical values. Vertical variability of the properties show sand fraction, soil pH, organic carbon and organic matter and electrical conductivity were low (CV < 15%) at the crest, middle and lower slopes. Silt showed high variability at all topographic positions while clay content was low at the crest and high at the middle and lower slopes. Lateral variability of the soil properties indicated high variability in clay fraction along the toposequence. Silt fraction, organic carbon and organic matter showed medium variability whereas pH, sand and electrical conductivity showed low variability. It was recommended that crop management practices on these soils should involve heavy inputs of manure with inorganic fertilizers to improve soil structure, nutrient supplying power and reduce risk of erosion.