Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 19: 1054 - 1064. Published July 7, 2009.
Growth performance of Pterocarpus angolensis seedlings in mycorrhizae colonized and uncolonized soils from high rainfall area of Zambia
Moola S. W., Muimba-Kankolongo* A. and Kangwa J.M.
Copperbelt University, School of Natural Resources, P.O. Box 21692, Jambo Drive, Riverside, Kitwe, Zambia
^Corresponding author e–mail:kankolongo@cbu.ac.zm or ambayeba@yahoo.com
ABSTRACT
Objectives: Pterocarpus angolensis trees are being harvested at an alarming rate in Zambia because of its high value timber. Considering the low number of seedlings that recruit into adults in forests, efforts have been devoted without success to propagate trees in nurseries. This study aimed at formulating a suitable growth substrate to foster its propagation in nurseries.
Methodology and results: Soils underneath maturetrees were collected and examined for the presence of beneficial microorganisms. Laboratory analysis confirmed mycorrhizal contamination. Then, four subset soil treatments were constituted and amended with chicken manure to enhance plant growth. They were (1) sterilized soil without chicken manure in which mycorrhizae were destroyed, (2) sterilized soil with manure, (3) unsterilized soil without manure and (4) unsterilized soil with manure used in a completely randomized experiment with four replications to grow P. angolensis seeds. Seed germination was assessed, and plant height, diameter, taproot length and biomass were recorded 30 and 70 days after germination. There was no difference in seed germination rate between soil treatments. However, significant statistical differences were found between soil treatments (P≤0.05) for all the plant growth parameters assessed. Mycorrhizae-colonized soils amended with chicken manure consistently resulted in significantly enhanced seedling growth and profuse plant biomass production. Seedlings in mycorrhizae-colonized soil with chicken manure had 7.94% and 5.94% overall increment in height and stem collar diameter, respectively compared to 5.64, 5.28 and 6.85% height increment and between 3.33 and 4.64% collar diameter increment for the other treatments.
Conclusion and application of findings: The growth of P. angolensis seedlings in nurseries can be improved by adding chicken manure and mycorrhizal inocula to the soil substrate. This silvicultural management is cost-effective, as no fertilizers are needed since mycorrhizae increase considerably plant uptake of nutrients mainly phosphorous and nitrogen. The enhanced seedling growth achieved necessitates expanded field testing of the technology to ensure the feasibility of wider afforestation and reforestation programs that have great potential for P. angolensis conservation in Zambia and within the region.
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