Investigating Trace Element (Micronutrient) Availability/Contamination in Soils within Niger State Using Geospatial Techniques

Abstract

Trace elements are chemical elements found in small concentrations within soil, and are also known as minor elements or micronutrients. Examples include boron, copper, iron, manganese, molybdenum, and zinc. While present in small amounts, they play vital roles in plant and animal nutrition and can have significant environmental impacts if levels become too high. The transfer of trace elements between soil phases represents the primary processes controlling their behaviour and bioavailability. This study examines the distribution of trace elements in soils within Lapai and Agaie Local Government Areas (LGAs), Niger State, Nigeria. The ever-increasing pressure on land for agriculture, mining, and other activities continuously disrupts the balance, concentrations, and mobility of various trace elements. In many cases, deficiency or toxicity of micronutrients affects plant growth, reducing yield, stunting development, and causing premature leaf drop, among other symptoms.
A total of fifty (50) soil samples were systematically collected from different sites across mining areas of Lapai and Agaie LGAs and transported to the Centre for Dryland Agriculture, Bayero University Kano, where comprehensive chemical analysis was conducted. The laboratory results were subsequently subjected to Inverse Distance Weighted (IDW) spatial interpolation to examine the distribution patterns of trace elements across the study area. For copper, a concentration range of 1.1 to 3 mg/kg (ppm) was observed. Zinc concentrations ranged from approximately 2 to 14 mg/kg, while iron concentrations ranged between 147 and 240 mg/kg (ppm). Manganese concentrations were generally below typical levels, ranging between 17 and 32 mg/kg. Trace element levels in soils within the study area are generally adequate, with no toxicity detected and only minor deficiencies of manganese, copper, and zinc. Targeted management of manganese levels may be required to achieve optimum soil and plant health.