Tree species screened on nitosols of Central Ethiopia: biomass production, nutrient contents and effect on soil nitrogen
2006
G. Glatzel | M. Kindu | Y. Tadesse | A. Yosef
Shortage of tree biomass is asevere problem in the highlands of Ethiopia. A screening trial was conducted from 1997 till 2002 to selectfast growing and high biomass producing tree species, evaluate foliage and wood macronutrient contentsof different tree species, and assess effect of tree species on soil nitrogen beneath their canopies. Seven treespecies: (i) Acacia decurrens, (ii) Chamaecytisus palmensis, (iii) C. proliferus, (iv) Eucalyptus globulus, (v) E.camaldulensis, (vi) Grevillea robusta and (vii) Hagenia abyssinica were evaluated in a randomized completeblock design with three replications. All species were exotic except H. abyssinica. Grevillea robusta exhibitedslow height growth and wood production as compared with the five exotic species. Acacia decurrens providedthe highest mean dry biomass at 64 months. Foliar N levels in A. decurrens, C. palmensis and C. ploriferus weresignificantly higher than those in the other four tree species. Acacia decurrens, C. palmensis and C. ploriferusare N-fixing tree species. Hagenia abyssinica had higher K levels in the foliage and wood. Eucalyptus speciestended to deplete soil fertility whereas C. palmensis and C. ploriferus improved soil fertility. Chamaecytisusspecies and A. decurrens can be short-term options for soil fertility improvement and a source of fuelwoodrespectively
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