Impact of Cannabis sativa cultivation on soil physicochemical properties in Akure Forest Reserve, Ondo State, Nigeria

Abstract

The conversion of forest estates to other land use, particularly cannabis plantations, could have a detrimental effect on soil health and production. However, the impact of this practice on the physical and chemical properties of soil in this forest reserve is not known. This study was carried out in Akure Forest Reserve, Ondo State. Soil samples were collected at four depths and from four distinct areas of this forest: the undisturbed area, the degraded area without hemp, the degraded area with hemp in 2020, and the degraded area with hemp in 2023. Determination of soil physical and chemical characteristics was done using the Bouyoucos hydrometer, Walkley-Black net oxidation and potentiometer methods. Soil physical properties in this forest varied with depth and among the forest classes. In the undisturbed area of the forest, the study revealed that sand content decreased with depth, clay content increased with depth, while the silt content was the same with depth. Both soil physical and chemical properties were adjudged poor in all the degraded classes, revealing the potential of anthropogenic activities, particularly activities related to hemp planting, to destroy soil structure and health. These activities could lead to the destruction of the soil seed bank, resulting in poor regeneration and deficient tree growth. To avert deforestation and other negative consequences that may be occasioned by hemp planting activities, government should discourage forest destruction for Hemp planting and implement sustainable forest management practices.