Influence of Municipal Solid Waste Vermicompost on Soil Organic Carbon Stock and Yield of Okra (Abelmoschus esculentus Moench) in a Tropical Agroecosystem

Abstract

A three year trial was conducted in a farmers’ field within the degraded Abraka Forest Farm Reserve about 5km from the Teaching and Research Farm of the Delta State University, Abraka, (latitude 5⁰ 46’ and longitude 6⁰ 5’) Nigeria in early cropping (March-July) and late cropping (August-December) of 2010, 2011 and 2012. The study was aimed at determining the influence of vermicompost application on soil organic carbon stock and crop yield in an okra based vegetable farm. Six treatments, namely: control (no application), 100%NPK, 100%vermicompost, 85% vermicompost + 15%NPK, 50% vermicompost + 50%NPK and 15%NPK + 85% vermicompost, were arranged in a randomized complete block design. Soil fertility attributes studied were soil bulk density, soil organic carbon and soil organic carbon stock, while pod yield was the only plant parameter. Vermicopmost application significantly reduced soil bulk density, and increased soil organic carbon (SOC) and carbon stock. Agronomic efficiency indices (AEI) of vermicompost for all the soil fertility attributes and pod yield were more efficient than NPK by values above 100%. Highest cumulative marketable fruit yield of okra over the three years was obtained with 100% VC with value of 67.04tons ha^-1 and increased by 94.8% and 73.8% over the control and 100%NPK respectively.

Keywords: okra, soil organic carbon, agronomic efficiency index, vermicompost, solid wastes