Measuring the Extent of Restoration using Coffea Arabica L. as a Bioassay Plant
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Date
2013-07
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Addis Ababa University
Abstract
This study was undertaken as part of the ongo ing biological restoration efforts at
the "Center for Indigenous Trees Propagation and Biodi versity Development in Ethiopia"
(50·55 Km west of Addis Ababa, 09°01' 188" N; 038~1'566" E). The main objective of
the study was to measure extent of restoration over a degraded landscape usi ng CoJJea
arabica L. as a bioassay plant. In order to measure this, the phrase " Restoration Bioassay"
was coined for coffee plants which were established beneath Acacia abysl'inica, Croton
macrostachYlil' and Ellclea divinorum. The trees were regenerated after 5-6 years' of
intensive restorat ion acti vi ties. All the vegetat ive and reproductive responses were
quantified on randomly se lected 3 to 5 year·o ld coffee plants. Al so, soil samples from the
si tes being restored, and those From the non- restoring adjacent areas were collected and
analyzed for macro- and micro-n utrients, as well as for texture, moisture, density and
elect rical conduct ivi ty. Through thi s study, it was found that mean number of nodes,
leaves, as well as internode lengths were significantly (P<0.05) greater for coffee plants
establ ished and maintained for 3-4 years beneath the A. abyssinica shades, compared to
those beneath the C. mocros/(lchYlIs and E. divillorllm shades. Although no significant
difference was found in height growth. mean leaf area of coffee plants that benefited by
the shade of A. abyssinica was different, compared to those grown beneath the shades of
C. macrostachYlis or E. divinorlll1l. Further, key phys iological and/or economic indices
such as number of green berries, fresh weight of berries, s ize of beans, mature red berry
harvest per plant, berry to bean ral io, weight of bean per berry. as well as weight per 1000
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beans were all sign ifican tly (P<O.05) higher in coffee plants grown under A. abyssi"ica
than those grown under either C. macroslachyus or E. dilli"orulfl. Significant (P<O.OOI)
differences in the number of flower buds and flowers were observed between the control
and treatment groups in coffee plants where GAJ levels of 100, 250 and 350 mg 1'1 were
sprayed on the l eavl~ s. Soil analyses results yielded signi ficant (P<0.05) diffe rences in
soil phosphorous, total ni trogen, organic carbon, potassium and electrical conductivi ty
between the sites being restored through use of native trees and shrubs and those that have
not been restored. Compared to the non-restoring adjacent sites, the leve ls of avai lable
phosphorous, total nitrogen and organic carbon were found to be 54, 39 and 56 % higher,
respectively, in the sites that were in the process of restoration. This study showed that
restoring native trees, shrubs, herbs and grasses over a degraded landscape restores
keystone natural resources wi th fa r-reachi ng pos it ive consequences on economic growth,
food security, biodiversi ty, and livelihood restoration. We, therefore, recommend that
landscape restoration using native trees and shrubs must be scaled-up using mechanisms
detailed in this thes is. Further, since Ethiopia's nature and natural resources have been
dilapidated for generat ions, and since the nation's poverty has been the direct
consequences of these actions, biological restoration must be considered Ethiopia's
priority agendum both by lawmakers and the Government that enforces the laws.
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Keywords
Coffee reproductive traits; Degraded landscapes; Ethiopia; Indigenous trees; Restoration Bioassay