Abstract
Enset (Ensete ventricosum),
commonly known as false banana, is a large thick, single-stemmed,
perennial herbaceous banana-like plant growing in the wild of sub-Sahara
Africa, Madagascar and parts of Asia. In Ethiopia it has been
domesticated and serves as a food plant. While the productivity and
management of enset for food (pseudostem and corm) has been studied,
little attention has been given to total biomass production and
associated carbon sequestration. The objective of this study was to
develop and evaluate allometric models for estimating above and
belowground biomass and organic matter contents of enset grown in
indigenous agroforestry systems in Rift Valley escarpment of
south-eastern Ethiopia. Biomass harvesting of 40 plants was carried out
at altitudes from 1900 to 2400 m.a.s.l. The mean plant dry weight was
9.4 ± 0.84 kg and organic matter content 94 %. Pseudostem biomass
accounted for highest (64 %) of total biomass, followed by corm (24 %)
and foliage (12 %). Basal diameter (d
10) was the best predictor variable for total and all biomass components (Spearman r = 0.775–0.980, p < 0.01). The power model using d
10 and height (H) (Y = 0.0007d
10
2.571
H
0.101; R
2 = 0.91)
was found to be the best performing model (highest ranking over six
good-of-fit statistics) for predicting total biomass. Model performance
decreased in the order pseudostem > corm > foliage biomass. The
models presented can be used to accurately predict biomass and organic
matter of enset in the agroforestry systems of Rift Valley escarpments
Ethiopia.
Mesele Negash, Mike Starr, Markku Kanninen, Leakemaraiam Berhe. 2013. Allometric equations for estimating aboveground biomass of Coffea arabica L. grown in the Rift Valley escarpment of Ethiopia. Agroforest Syst. DOI 10.1007/s10457-013-9611-3.
Mesele Negash, Mike Starr, Markku Kanninen, Leakemaraiam Berhe. 2013. Allometric equations for estimating aboveground biomass of Coffea arabica L. grown in the Rift Valley escarpment of Ethiopia. Agroforest Syst. DOI 10.1007/s10457-013-9611-3.
Abstract
Coffee, Coffea arabica
L., which is native to Ethiopia, is the world’s most widely traded
tropical agricultural commodity. While much is known about the
productivity and management of coffee for coffee beans little attention
has been given to the plants overall biomass production and carbon
sequestration. The objective of this study was to develop and evaluate
allometric equations for estimating the aboveground biomass of C. arabica
plants growing in indigenous agroforestry system in the Rift Valley
escarpment of south-eastern Ethiopia. Coffee plays an important role in
providing income and in sustaining these productive systems. Biomass
harvesting of 31 plants with 54 stems was carried out in a 40 km2
area varying in elevation from 1,500 to 1,900 m. The stem accounted for
most (56 %) of plant biomass, followed by branches (39 %) and twigs
plus foliage (5 %). Plant mean biomass was 22.9 ± 15.8 kg. Power
equations using stem diameter measured at either 40 cm (d
40) or at breast height (d, 1.3 m) with and without stem height (h) were evaluated. The square power equation,
Y=b1d240
, was found to be the best (highest
ranked using goodness-of-fit statistics) for predicting total and
component biomass. The reliability of the prediction decreased in the
order: stem > branches > twigs plus foliage. A cross-validation
procedure showed that equation parameterization was stable and
coefficients reliable. Our parameterized square power equation for total
aboveground biomass was also found to be better than the equations
parameterized by Hairiah et al. (Carbon stocks of tropical land use
systems as part of the global C balance: effects of forest conversion
and options for clean development activities, International Centre for
Research in Agroforestry, Bogor, 2001) and Segura et al. (Agroforest Syst 68:143–150, 2006) for C. arabica
grown in agroforestry systems, confirming the importance of
parameterization of allometric equations with site specific data when
possible.
