Influence of salinity on soil chemical properties and surrounding vegetation of Awe salt mining site, Nasarawa State, Nigeria

Abstract

This study was carried out to monitor and document the influence of salinity on soil chemical properties and surrounding vegetation of Awe salt mining site, Nasarawa State, Nigeria. The soil samples were collected randomly from the salt mining site and 10 m away from the site (control) at 5, 10, 15 and 20 cm depths, respectively, with three replications each. The soil samples were air dried, sieved and the physical and chemical properties were determined using standard methods. The exchangeable sodium percentage (ESP), cation exchange capacity (CEC) and sodium adsorption ratio (SAR) were calculated. No plant was found growing on the salt mining site (SMS) unlike the control site (CTS) which has a little diversity of plants. The soil organic carbon, organic magnesium, total nitrogen and phosphorus at SMS decreased significantly (α = 0.05) with soil depth in relation to CTS except for 10-15 cm soil depth. Soil exchangeable acidity (H⁺ and Al³⁺) at SMS significantly increased (α = 0.05) when compared with the CTS at different soil depths. Also, K⁺, Na⁺ and Mg²⁺ of SMS and CTS significantly increased (α = 0.05) at the different soil depths. Soil pH, electrical conductivity (EC), ESP and SAR at SMS significantly increased at different depths when compared with CTS. Awe salt mining has brought about soil nutrient imbalance at CTS with EC less than 0.2 dS/m and SAR between 0-3. Thus, it is concluded that soil at CT and SMS is a sodic soil which have reduced the diversity of plants species.

Key words: Cations exchange, mining, salinity, sodicity, Awe town.