Impacts of Eucalyptus plantation on soil physico-chemical properties in Bamunanika sub-county, Luwero district, Uganda.

Abstract

Eucalyptus is very important to people’s livelihood as source of income and ecosystem services. However, issues surrounding these eucalyptuses on soils and the environment have raised unresolved debates among conservationists and natural resource managers. Therefore, this study was carried out to assess the impact of eucalyptus on selected soil physicochemical properties in Bamunanika county Luwero district, where cultivation of Eucalyptus has been identified as a priority practice for integrated watershed management. A study area with both natural forest and Eucalyptus plantation was selected in Bamunanika subcounty. A 20-m long transect emanating from each of the two land use types (Eucalyptus vs. natural forest) was set up. Along each transect, a soil sample was taken from the distances 0, 5, 10, 15 and 20 m from the edge of the land use type. Four undisturbed core samples were taken using pF rings and core sampler from each of the sampling points (within 40 cm of each other on either side of the transect) and uniquely labelled prior to transportation to the lab for bulk density determination. Four cores were taken at each sampling point, parallel to the edge of the land use type and composited. The samples were air-dried, ground and sieved to pass through 2-mm mesh and then analyzed for the chemical properties (pH, total N, soil organic matter, available P and exchangeable bases). Soil analyses were done using standard laboratory methods. The data subjected to linear regression with groups in GenStat 15. The soil bulk density under the Eucalyptus spp. plantation (1.6 g cm-3) was significantly higher compared to that of the native forest (1.06 g cm-3). Exchangeable calcium and total nitrogen were also significantly higher in natural forest compared to the Eucalyptus land use.