MORPHOLOGICAL AND PHYSICAL CHARACTERIZATION OF SOILS AS INDICATORS OF SOIL DEGRADATION IN LAUTECH ISEYIN CAMPUS, NIGERIA

Abstract

Soil degradation is the decline in the physical, chemical, and biological quality of soil, remains one of the most pressing global environmental challenges, threatening agricultural productivity and the stability of ecosystems. Human activities such as deforestation, overgrazing, and unsustainable farming practices, together with the increasing effects of climate change like flooding and erosion, have multiple effects on soil degradation. The study examined the land use types, evaluate the effects of farming practices on soil properties, and propose sustainable management strategies to reduce degradation and improve soil health at LAUTECH, Iseyin campus, Oyo state. The study was, conducted at Iseyin campus Oyo State, which lies on latitude 7°58'N longitude 3°36'E within Southern Guinea Savanna Zone. A rigid grid sampling method was used across 30,000 m² area, with transverses cut at 100-meter intervals. Nine profile pits (1.5 m × 1.5 m × 2.0 m) were dug at each point, from which undisturbed soil samples were collected at 0-15cm depths. Laboratory analyses were conducted to determine particle size distribution, pH, exchangeable acidity, available phosphorus, organic carbon, total nitrogen and exchangeable bases (Ca, Mg, K, and Na). Field
descriptions and degradation classifications followed the FAO guidelines. The study revealed that soils in profiles 1, 2, 4, 5, and 6 were in good condition and classified as Class 1 (non or slightly degraded), while profiles 3, 7, and 8 showed Class 2 (moderate degradation) under
FAO standards. The soils were mainly sandy loam, with sand content ranging from 66.8 to 89.2%, silt from 7.4 to 17.4%, and clay from 3.4 to 24.8%. Nitrogen (0.09-0.34%) and organic carbon (0.84-3.11%) levels indicated moderate degradation in some areas, particularly in profiles 3, 7, and 8. Phosphorus (8.0-38.65 mg/kg) and cation exchange capacity (8.08-13.26 cmol/kg) values were generally adequate, placing most soils in Class 1. Soil pH ranged from 5.62 to 6.84, showing slightly acidic to near-neutral conditions suitable for crop growth. Exchangeable bases and cation exchange capacity varied across profiles, while aluminium toxicity was minimal, appearing only in the basement complex horizon of profile 6. Overall, the soils are largely fertile and suitable for sustainable agricultural use, with only localized areas showing moderate degradation. Most soils within LAUTECH, Iseyin campus are in good condition, showing only slight to moderate degradation and are largely suitable for sustainable agricultural use, although localized areas with reduced nitrogen and organic carbon require attention to prevent further decline. Appropriate soil management practices such as organic matter incorporation, controlled fertilizer application, use of contour farming, continuous soil fertility monitoring, and conservation-oriented land-use planning should be adopted to ensure sustained long-term soil productivity.