Pre‐ and Post‐Mined Bauxite Soils of Jamaica: Physical and Chemical Properties

Abstract

Earthy bauxite (aluminum ore) deposits over limestone bedrock cover over 20% of Jamaica's surface area. With the shortage of arable land in Jamaica, there is great interest in using post‐mined bauxite lands for agriculture. The purpose of this study was to compare physical and chemical properties of pre‐ and post‐mined bauxite soils that are relevant in assessing suitability of these lands for small‐scale agriculture. Pedons were described and sampled for characterization at two pre‐mined sites and four post‐mined sites near Mandeville, Jamaica. Post‐mined soils were generally steeper, shallower, and higher in limestone rock fragments than pre‐mined soils. Pre‐mined soils consisted of Ap and Bo horizons making up clayey Oxisols with low charge and low bulk density. The new caret (^) symbol, which indicates horizons formed from human transported material, was helpful in describing pedons of post‐mined soils. Post‐mined soils consisted of ^Ap horizons (replaced topsoil) and 2^C horizons (fill material) over limestone. Some post‐mined pedons also had 2Bob or 3Bob horizons (Bo in situ buried by replaced topsoil and/or fill material). Post‐mined soils had higher bulk density in the ^Ap horizons than pre‐mined Ap horizons and higher pH throughout due to the incorporation of limestone rock fragments. In ^Ap horizons, organic matter and granular structure increased with time after reclamation and establishment of grass cover.