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Soil organic carbon in Upper East Region, Ghana : mesaurements and modelling

Dawidson, Elisabeth and Nilsson, Cecilia (2000) In Lunds universitets Naturgeografiska institution - Seminarieuppsatser
Dept of Physical Geography and Ecosystem Science
Abstract (Swedish)
Populärvetenskaplig sammanfattning: Som ett svar på den förstärkta växthuseffekten föreslogs vid Kyotokonferensen 1997 en
handel med utsläppsrättigheter och åtgärder som reducerar koldioxidhalten i
atmosfären. De påvisat ökade halterna av koldioxid i atmosfären har uppmärksammat
kolcykeln och visat på behovet av en ökad kunskap om den globala kolcykeln. Detta kan
uppnås med hjälp av ekologiska modeller. En av dem är ”CENTURY soil organic matter
model”.
I denna studie utvärderas CENTURY, och påverkan av olika markanvändning och
odlingsintensitet på kolinnehållet i jorden undersöks. Fältstudien har utförts i det
semiarida Upper East Region i Ghana, emedan savanner har en stor potential för upptag
av kol. Jordprover togs i februari... (More)
Populärvetenskaplig sammanfattning: Som ett svar på den förstärkta växthuseffekten föreslogs vid Kyotokonferensen 1997 en
handel med utsläppsrättigheter och åtgärder som reducerar koldioxidhalten i
atmosfären. De påvisat ökade halterna av koldioxid i atmosfären har uppmärksammat
kolcykeln och visat på behovet av en ökad kunskap om den globala kolcykeln. Detta kan
uppnås med hjälp av ekologiska modeller. En av dem är ”CENTURY soil organic matter
model”.
I denna studie utvärderas CENTURY, och påverkan av olika markanvändning och
odlingsintensitet på kolinnehållet i jorden undersöks. Fältstudien har utförts i det
semiarida Upper East Region i Ghana, emedan savanner har en stor potential för upptag
av kol. Jordprover togs i februari år 2000, vid markytan och på 20 cm djup, i obrukade
områden, kontinuerligt odlade fält och i fält med trädesperioder. Klimatdata,
jordbruksdata och data om jordegenskaper samlades in och användes i modellen. Det
simulerade kolinnehållet jämfördes med det observerade för att utvärdera hur användbar
modellen är.
Högst kolinnehåll uppvisade obrukade områden, medan odling visade sig ha en
minskande effekt på kolinnehållet. Fält med trädesperioder hade ett lägre kolinnehåll än
kontinuerligt odlade fält. Gödsel ökade kolhalterna och utövade ett viktigt inflytande över
kolinnehållet. De finare kornstorleksfraktionerna var korrelerade med kolinnehållet i
kontinuerligt odlade fält och i obrukade områden. En signifikant korrelation mellan
observerat och simulerat kolinnehåll påvisades endast i fält med trädesperioder, där det
simulerade kolinnehållet var 10% högre än det observerade. Slutsatsen av våra resultat
är att CENTURY, med tillgänglig data, inte är tillräckligt bra för uppskattning av
kolinnehållet i jorden i denna miljö, där tillförseln av gödsel är hög. Endast en utav de
tre markanvändningsklasserna erhöll signifikanta simulerade kolvärden vid jämförelse
med observerade kolvärden. Trovärdheten i korrelationen mellan dessa avspeglas i
insamlad data, modellens struktur eller en kombination av de båda. (Less)
Abstract
As a response to the enhanced greenhouse effect International Emissions Trading and
Clean Development Mechanism were proposed as countermeasures at the Kyoto climate
conference, in 1997. The observed raise in levels of atmospheric carbon dioxide has
increased attention on the carbon cycle and claimed the need of more knowledge and
understanding of the global carbon cycle. This can be obtained by the use of ecological
models. One of these is the CENTURY soil organic matter model.
In this study, we evaluate the CENTURY model and investigate what effect different land
use and cultivation intensity has on carbon content in soil. The field study was performed
in the semi-arid Upper East Region of Ghana, since savannas have large... (More)
As a response to the enhanced greenhouse effect International Emissions Trading and
Clean Development Mechanism were proposed as countermeasures at the Kyoto climate
conference, in 1997. The observed raise in levels of atmospheric carbon dioxide has
increased attention on the carbon cycle and claimed the need of more knowledge and
understanding of the global carbon cycle. This can be obtained by the use of ecological
models. One of these is the CENTURY soil organic matter model.
In this study, we evaluate the CENTURY model and investigate what effect different land
use and cultivation intensity has on carbon content in soil. The field study was performed
in the semi-arid Upper East Region of Ghana, since savannas have large potentials for
carbon sequestration. Soil samples were taken in February of 2000, at the surface and at
20 cm depth in uncultivated areas, continuously cultivated fields and in fields with fallow
periods. Data regarding climate, soil management and soil properties were gathered and
entered into the model. Simulated carbon content was compared with observed carbon
content to evaluate the usefulness of the model.
The highest carbon content existed in uncultivated areas, whereas cultivation was found
to have a decreasing effect on the carbon content. Fields with fallow periods had lower
carbon content than continuously cultivated fields. Manure increased carbon levels, and
exerted an important influence over soil organic carbon. The finer soil fractions were
correlated with the carbon content in continuously cultivated fields and in uncultivated
areas. A significant correlation between observed and simulated carbon content did only
exist on fields with fallow periods, where CENTURY overestimated the carbon content
with 10%. The conclusion of our results is that simulations with CENTURY, using
available data, are not suitable for estimations of carbon content in an environment with
this high application of manure, since the model only could estimate true content in one
of the three land use classes. The credibility of the correlation between observed and
simulated carbon content is reflected by gathered information, by the structure of the
model or by a combination of them both. (Less)
Please use this url to cite or link to this publication:
author
Dawidson, Elisabeth and Nilsson, Cecilia
supervisor
organization
alternative title
Jordbundet organiskt kol i Upper East Region, Ghana : mätningar och modellering
year
type
H1 - Master's Degree (One Year)
subject
keywords
pedology, geomorphology, physical geography, Africa, carbon cycle, greenhouse effect, atmospheric carbon dioxide, cartography, climatology, naturgeografi, geomorfologi, marklära, kartografi, klimatologi
publication/series
Lunds universitets Naturgeografiska institution - Seminarieuppsatser
report number
77
funder
SIDA, Minor Field Study programme (MFS)
language
English
additional info
Prof. Seth K. A. Danso, supervisor in Ghana and director of
Ecolab Centre, Department of Geography and Resource Development.
id
1332833
date added to LUP
2005-10-27 00:00:00
date last changed
2011-11-30 14:44:39
@misc{1332833,
  abstract     = {{As a response to the enhanced greenhouse effect International Emissions Trading and
Clean Development Mechanism were proposed as countermeasures at the Kyoto climate
conference, in 1997. The observed raise in levels of atmospheric carbon dioxide has
increased attention on the carbon cycle and claimed the need of more knowledge and
understanding of the global carbon cycle. This can be obtained by the use of ecological
models. One of these is the CENTURY soil organic matter model.
In this study, we evaluate the CENTURY model and investigate what effect different land
use and cultivation intensity has on carbon content in soil. The field study was performed
in the semi-arid Upper East Region of Ghana, since savannas have large potentials for
carbon sequestration. Soil samples were taken in February of 2000, at the surface and at
20 cm depth in uncultivated areas, continuously cultivated fields and in fields with fallow
periods. Data regarding climate, soil management and soil properties were gathered and
entered into the model. Simulated carbon content was compared with observed carbon
content to evaluate the usefulness of the model.
The highest carbon content existed in uncultivated areas, whereas cultivation was found
to have a decreasing effect on the carbon content. Fields with fallow periods had lower
carbon content than continuously cultivated fields. Manure increased carbon levels, and
exerted an important influence over soil organic carbon. The finer soil fractions were
correlated with the carbon content in continuously cultivated fields and in uncultivated
areas. A significant correlation between observed and simulated carbon content did only
exist on fields with fallow periods, where CENTURY overestimated the carbon content
with 10%. The conclusion of our results is that simulations with CENTURY, using
available data, are not suitable for estimations of carbon content in an environment with
this high application of manure, since the model only could estimate true content in one
of the three land use classes. The credibility of the correlation between observed and
simulated carbon content is reflected by gathered information, by the structure of the
model or by a combination of them both.}},
  author       = {{Dawidson, Elisabeth and Nilsson, Cecilia}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Lunds universitets Naturgeografiska institution - Seminarieuppsatser}},
  title        = {{Soil organic carbon in Upper East Region, Ghana : mesaurements and modelling}},
  year         = {{2000}},
}