Soil fertility status of soils of Sudano-Sahelian and Humid Forest Zones of West Africa and some soil management strategies for smallholder farms

Abstract

Knowledge of soil properties and fertility status of farmers’ fields are basic information needed by Agricultural Extension Agents to guide farmers on wise and sustainable management of soil. The properties of some cultivated fields in the Sudano-Sahelian of Ghana and Humid Forest zones of Nigeria were studied. The aim was to quantify the soil properties and fertility status with a view to prescribing low input ecological technologies that would improve and sustain soil productivity.  Core samples were taken from the depth of 0 – 40 cm in eleven and eight farmers’ fields in the Upper East Ghana and South East Nigeria, respectively.  Soil properties determined using standard methods were; pH, TN, SOC, SOM, P, Exchangeable bases, EA, base saturation, PSD, WP, FC, bulk density, P and SHC.  Both soils were sand in texture (> 700 g kg^-1). The WP and FC were either below or within the lower border of critical levels. This shows crops in all the fields are prone to incipient wilting under any short dry spell. The chemical properties of the Sahelian-Sahelian zone showed that pH averaged 6.54 (moderate acidic), SOC 16 g kg^-1 (low), TN 13 g kg^-1 (very high), P, 18 mg kg^-1 (moderate), K 0.23 C mol kg^-1) (moderate), ECEC 8.18 C mol kg^-1(medium fertility class). In the Humid Forest zones, pH was 4.38 (extremely acidic), SOC 7.41 g kg^-1 (very low), N 1.78 g kg^-1 (low), P 15.94 mg kg^-1 (moderate), K 1.94 C mol kg^-1 (very high) and ECEC 8.8 C mol kg^-1 (medium fertility class).  The fertility class indicates that the soils will response to external inputs and wise land management practices. A mix of Arbuscular mycorrhizal fungus (AMF), multipurpose tree species, contour cultivation, organic mulch, multiple crop mixture, under vetiver grass buffer strip is recommended.