EVALUATION OF NUTRIENT STOCKS AND SOME SOIL INDICES OF AGRO-ECOSYSTEM AS AFFECTED BY LONG-TERM MONOCROPPING SYSTEM

Abstract

Objectives: This study investigates nutrients stock and some soil indices of agro-ecosystem soil as affected by monoculture cropping system (cacao plantation). This was with a view to provide comprehensive understanding of soil nutrient dynamics in the ecosystems due to their different management practices. \nMethods: The study was carried out in 0.063 ha sample plots, three each in natural forests and cacao plantations adjacent to each other. In each plot, five core soil samples were randomly collected at two depths (0–15 and 15–30 cm), bulked according to depth, air-dried, sieved through 2 mm sieve, and analyzed for soil physicochemical properties using standard methods. One-way analysis of variance was used to test significant mean differences of the soil properties among cacao plantation and natural forest at probability level (p≤0.05) at different soil depth. \nResults: The results showed that soil physical properties such as particle size distribution, moisture contents, and bulk density; chemical properties such as pH, exchangeable cation, organic carbon, organic matter, phosphorus, and sulfur from natural forest were higher than the soil properties in cacao plantation for both top and subsoil. Soil indices such as soil structural stability index, base saturation percentage, and sodium adsorption ratio were higher in natural forest ecosystem than the soil indices of cacao plantation. \nConclusion: From this study, it can be concluded that long-term monoculture cropping system had significant effect on nutrients stock and soil indices. This subsequently might result in permanent soil degradation and productivity.