Evaluation of land use impact on soil quality in Samaru College of Agriculture, Northern Guinea Savanna, Nigeria

Land use changes influence soil quality, which is of fundamental importance in sustainable crop production and environmental management. This study evaluated land use impact on soil quality at Samaru College of Agriculture farm, Ahmadu Bello University, Zaria, Nigeria. The land use types were Tomato/Pepper, Grapevine/Fluted pumpkin, Mango/Orange, and Guava/Mango. A profile pit was dug in each land unit. Soil samples were collected from genetic horizons, prepared, and analysed in the laboratory using standard methods. Sand, silt, and clay differed significantly (p < 0.05) among the land uses. The soil texture varied from clay loam to clay. Bulk density (BD) was significantly (p < 0.05) higher under Mango/Orange and Guava/Mango than other land use types. The soil reaction (pH) ranged from 5.0 to 5.8 and was strongly to moderately acidic. Soil organic carbon was low (< 10 g/kg), total nitrogen values of 0.19 – 0.24 g/kg were low, and available phosphorus values of 1.8 – 27.4 mg/kg were rated low to high across the land use types. Soils under the Grapevine/Fluted pumpkin land use type were significantly higher in organic carbon, exchangeable potassium, sodium, and effective cation exchange capacity than the other land use types. Soil quality under Grapevine/Fluted pumpkin was rated best (80 %), whereas soil quality under Tomato/Pepper land use type was the worst (40 %). The soils were low-to-high in quality and had a higher potential to support crop production if management practices that encourage the build-up of nutrients in the soil system were adopted. The application of manure, liming materials, and phosphorus-based fertilisers is advocated.