Human-altered soils — Signatures of Anthrosols and their potential for arable lands

Abstract

• Past human activities result in the formation of Anthrosols and the accumulation of nutrients.• Enrichment in physicochemical properties relates to the intensity of settlement activities.• The level of releasability contributes to the extended retention of nutrients in soils.• Past settlement sites represent nutrient-rich Anthrosols suitable for arable fields.The fertility of human-altered soils, Anthrosols, developed from past settlement activities for crop production is scarcely studied. The study evaluated the fertility of Anthrosols developed from the 15th to mid-20th century AD settlement in Old Buipe, Savanna region, Ghana, to determine whether abandoned localities are suitable for arable fields. Human activities enhanced the physical attributes of the Anthrosols: brown to dark brown intergrain fine soil, 15%–35% organic matter, 15%–30% potsherd, and 5%–15% charred materials. The Anthrosols were slightly acidic to neutral reactions \(\left({{\rm{p}}{{\rm{H}}_{\left[{{{\rm{H}}_2}{\rm{O}}} \right]}}\,5.67 - 6.83,\,\,{\rm{p}}{{\rm{H}}_{\left[{{\rm{CaC}}{{\rm{l}}_2}} \right]}}\,5.83 - 6.95} \right)\), high cation exchange capacity (CEC; 18.77–45.31me/100 g), electric conductivity (EC = 0.28–0.36 dS m−1), accumulation, and distribution of organic C, total N, P, Mn, Cu, Zn, K, and Fe, and available P, K, Ca, Mg, S, Mn, Fe, Cu, and Zn. Plant-available nutrients were comparatively higher than concentrations in non-anthropogenic soils. The level of releasability (bioavailable fractions of total concentrations) of P, K, Ca, Mn, Fe, Cu, and Zn partly compensates for low plant-available portions. Enrichment of chemical and physical properties of Anthrosols make them fertile for arable fields. The signatures of settlement activities are strong and can remain in soils for a long time, even under harsh environmental conditions.