Effects of exotic tree plantations of teak (Tectona grandis) and gmelina (Gmelina arborea) on a forest soil in south‐western Nigeria
ABSTRACT The properties of soil under 15-year-old plantations of gmelina (Gmelina arborea) and teak (Tectona grandis) were compared with logged forest soil in south-western Nigeria. The soil was significantly denser in the 0–10 cm layer of plantation soil and total porosity less than that of forest soil. Organic carbon was significantly greater in the 0–10 cm layer of forest soil. Similarly, the concentrations of total N, exchangeable Ca, Mg and K were greater under forest soil, but the concentrations of available P were similar under all three ecosystems. The smaller organic carbon and nutrient content of plantation soil is mainly due to its more open organic matter and nutrient cycles and nutrient immobilization in the fast-growing exotics.
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ABSTRACT: This paper examines the impact of a 33‐year plantation of Eucalyptus camaldulensis on an alluvial soil in Gaborone, south eastern Botswana, by comparing the soil under the plantation with similar soil under an adjoining native savanna woodland dominated by Acacia karoo. Soil clay content was significantly higher in the plantation soil in both the 0–10 cm and 10–20 cm layers. There were no significant differences between soil under the two ecosystems with respect to the levels of organic matter, exchangeable potassium and available phosphorus. Despite the higher clay contents of the plantation soil, exchangeable calcium and magnesium and pH were higher in soil under the native woodland. This suggests that E. camaldulensis immobilizes soil nutrients faster and that plantation nutrient cycles are less efficient than in the native Acacia woodland. Consequently, soil nutrient deficiency will limit plantation productivity after the first few rotations. It is important to adopt tree harvesting techniques that reduce drain on soil nutrients at the end of a plantation rotation.International Journal of Environmental Studies 01/2005; 62(2):163-170. DOI:10.1080/0020723042000275141
Archives of Agronomy and Soil Science 01/2015; DOI:10.1080/03650340.2014.990005
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ABSTRACT: The goal of this study to was compare soils of natural forests converted to teak (Tectona grandis Linn. F) plantations (21.3±5.1 years) in the Offinso and Juaso Forest Districts in the Ashanti region, Ghana. Sites selected for this study were in the moist semi‐deciduous forest zone and had nearly identical physiographic characteristics. In each of three natural forest stands and three teak plantations, 16 soil pits were examined and soil samples from the 0–20 (major rooting zone) and 20–40 cm depths were analyzed for selected chemical and physical properties. In the 0–20 cm depths bulk density significantly increased (1.17 to 1.30 g cm), but soil organic matter (OM) content (13 to 11%), total nitrogen (0.3 to 0.2 %), available phosphorus (4.2 to 1.2 mg kg), and exchangeable potassium (0.4 to 0.3 cmol(+)kg), calcium (17.0 to 12.4 cmol(+)kg), and magnesium (3.8 to 3.2 cmol(+)kg) significantly decreased in soils where natural forests were replaced with teak plantations. Similar results also were found for the 20–40 cm soil depths. The higher nutrient contents in soils under the natural forest may have been due to more litter contributions from understorey vegetation observed there. In the teak plantations nutrient leaching losses may have accelerated due to increased mineralization and the inability of teak to use the increase in available nutrient.Communications in Soil Science and Plant Analysis 02/2000; 31(3-4):355-373. DOI:10.1080/00103620009370442 · 0.42 Impact Factor