Soil organic carbon status in a vegetable cropping systems in Southern Benin: A rapid assessment

Abstract

Assessing and monitoring soil organic matter (SOM) is important for determining and developing management practices that will enhance agricultural soil quality. This study is aimed at assessing soil organic carbon (SOC) stocks and pools resulting from agricultural practices in the upper soil depths (0-10 cm and 10-20 cm) in vegetable cropping systems in peri-urban areas in southern Benin. The study was conducted on plots that have been amending since 2006 with poultry manure (S+PM) and sheep dung (S+SD). Two particle-size fractions of SOM: Particulate Organic Matter (POM: 2-0.053mm) and Fine Organic Matter (FOM: 0-.053mm) were separated at 0-10 cm and 10-20cm depths and their respective carbon contents were determined through Loss On Ignition (LOI) methods. Results showed that SOC stock was the highest in fallow with 22.93 t.ha-1and 25.87 t.ha-1 respectively at 0–10 cm and 10–20 cm depths. The cultivation leads to a depletion in organic carbon stocks compared to the herbaceous fallow. Although no significant difference was found for SOC stocks between S+PM and S+SD for the both depths, the PM application over the time could lead to increase in SOC stocks compared to the SD application. However, their SOC distribution in fraction is similar.