Bulk density and porosity of soils influenced by skidding operations in the Nkrankwanta Off-Forest Reserve of Ghana

Abstract

Heavy forest machinery used in skidding has the capacity to influence the physical properties of soils. These may possibly lead to an upsurge in soil disruption and compaction of the soil surface decreases forest soil fertilities. This study assesses the effects of skidding on some soil physical properties such as the soil bulk density and porosity in the Nkrankwanta off-forest reserve in Ghana. The treatments comprised of four traffic intensity levels (1, 5, 10, and 15 passes) of the Mercedes Benz skidder (MB) Trac 1800 and a slope of two levels (less than 20 % and greater than 20 %) in a completely randomized block design. In addition, porosity and soil bulk density were assessed at varied distances from the MB Trac 1800. Soil bulk density results showed increasing trends with traffic frequency. Soil bulk density measured in the undisturbed area was 0.64 g cm^-3 and 0.56 g cm^-3 at slopes of less than 20% and greater than 20%, respectively. On the skid trail, soil bulk density significantly increased with traffic frequency (p<0.05). However soil porosity declined. Soil porosity estimated in uninterrupted area was 59.10 % and 57.40 % at < 20% and > 20% slope, respectively. Soil porosity was significantly influenced via different skidder passes (p<0.05). The soil physical properties were not influenced by the steepness of the slope however acted together in the number of passes to influence soil porosity. The impacts of the skidder on soil physical properties were significantly apparent at distances of 2 m to each sideway of the skidding trail. In conclusion, distinct responsiveness ought to be considered throughout the operations of skidding to curtail unfriendly influences on soil physical properties in ground-base skidding.