Effect of land-use types on soil enzymatic activities and chemical properties in semi-deciduous forest areas of Central-West Cote d'Ivoire

Enzymatic activities play a key role in the biochemical functioning of soils. As a consequence, they have been proposed as indicators of soil quality. This study was conducted at the Oume benchmark site (Central-West, Cote d'Ivoire), and aimed at measuring the enzymatic activities involved in the phosphorus (acid phosphatase and alkaline phosphatase), nitrogen (N-acetyl-beta-D glucosaminidase) and carbon (beta-glucosidase and N-acetyl-beta-D glucosaminidase) cycles. Soil from four main agro-ecological units (a secondary forest, a 20 year-old cocoa plantation, a 2 year-old Chromolaena odorata-based fallow and a continuous maize crop), representative of land-use systems in the area, were sampled for the measurement of enzymatic activities and chemical characteristics. Results showed that the enzymatic activity values were the highest in the fallow soil, whereas the maize crop displayed the lowest levels of enzymatic activity in soil. Moreover, soil from C. odorata fallow displayed the highest values of C, N, exchangeable bases (Mg2+, K+) contents, and CEC, and the lowest C: N ratio, which are characteristics of good quality soil. A Principal Component Analysis revealed a marked relationship between C, N and enzymatic activity levels, showing that these enzymes are suitable for monitoring soil quality in semi-deciduous forest areas in Central-West Cote d'Ivoire.