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Relating soil properties to biomass consumption and land management in semiarid Sudan : a minor field study in North Kordofan

Thorstensson, Helen (2009) In Lunds universitets Naturgeografiska institution - Seminarieuppsatser
Dept of Physical Geography and Ecosystem Science
Abstract (Swedish)
I Sudan och många andra delar av Afrika är biomassa den huvudsakliga energikällan.
Ved används för att göra upp eld till matlagning och uppvärmning av hus och mycket
biomassa går också åt till att bygga hus, staket, verktyg och annat. Bönderna på den
sudanesiska landsbygden är väl medvetna om att Acacia-träden som växer och förökar
sig naturligt på deras marker hjälper till att öka bördigheten och skörden om de får
ligga i träda ett antal år innan de åter brukas. Under åren i träda kan arterna A. senegal
och A. seyal tappas på gummi arabicum, ett naturligt stabiliseringsämne som bland
annat används i mat, läskedrycker och inom industrin och som är en extra inkomst för
bönderna. Det så kallade ’bush fallow’-systemet är vanligt... (More)
I Sudan och många andra delar av Afrika är biomassa den huvudsakliga energikällan.
Ved används för att göra upp eld till matlagning och uppvärmning av hus och mycket
biomassa går också åt till att bygga hus, staket, verktyg och annat. Bönderna på den
sudanesiska landsbygden är väl medvetna om att Acacia-träden som växer och förökar
sig naturligt på deras marker hjälper till att öka bördigheten och skörden om de får
ligga i träda ett antal år innan de åter brukas. Under åren i träda kan arterna A. senegal
och A. seyal tappas på gummi arabicum, ett naturligt stabiliseringsämne som bland
annat används i mat, läskedrycker och inom industrin och som är en extra inkomst för
bönderna. Det så kallade ’bush fallow’-systemet är vanligt förekommande i Sahel
men långa perioder av torka under de senaste decennierna har bidragit till att många
bönder kortat ner trädaperioden, då behovet av odlingsbar mark ökat. Avsaknaden av
vegetation gör marken mer sårbar för erosion och behovet av åkermark blir än större
då mängden näringsämnen i jorden minskar. Torrområdena i Afrika ses som en hittills
outnyttjad sänka av atmosfärisk koldioxid och det är just i marken den största andelen
tros kunna lagras.
I den här studien görs en jämförelse av två byar med olika fokus gällande
markanvändning; den ena har fokus på produktion av gummi arabicum och
bevarandet av träd medan den andra i större utsträckning producerar grödor till
försäljning. Syftet med studien är att se huruvida det finns skillnader i jordegenskaper
mellan de båda och om detta kan tillskrivas konsumptionen av biomassa och valet av
markanvändning. Som ett sista steg utvärderas stabiliteten och framtidsutsikterna för
de båda strategierna. Metoderna som använts innefattar jordprovtagning, mätning och
beräkning av trädbiomassa samt intervjuer gällande hushållens förbrukning av
biomassa samt tidigare markanvändning i respektive by.
I motsats till vad som förväntades, visade resultaten inte någon tydlig trend åt något
håll gällande jordegenskaperna. Den största anledningen till detta tros vara att byarna
inte var så olika trots allt. Den årliga förbrukningen av biomassa överskred inte
produktionen i någon av byarna och den största oron för framtiden är sannolikt
tillgången på dricksvatten. Intervjuerna avslöjade att bristen på vatten är den
huvudsakliga anledningen till att många människor tillfälligt flyttar från byn under
torrperioden och allt fler förväntas göra det om temperaturen stiger och mängden regn
minskar. (Less)
Abstract
In rural Sudan, as in many parts of Africa, biomass is the most important source of
energy. Besides the use as fuelwood for cooking and heating of houses, biomass is
also used for construction of houses and fences amongst other things. Among farmers
in semiarid Sudan it’s a known fact that the Acacia trees that grow and regenerate
naturally on their lands help improve soil fertility and crop yield if left as fallow for
some years before cultivating it again. During fallow the A. senegal and A. seyal trees
can be tapped for gum Arabic, a resin used in food, beverages as well as for industrial
purposes, as an extra source of income. This so called bush fallow system is
commonly used in Sahel, but droughts during recent decades has... (More)
In rural Sudan, as in many parts of Africa, biomass is the most important source of
energy. Besides the use as fuelwood for cooking and heating of houses, biomass is
also used for construction of houses and fences amongst other things. Among farmers
in semiarid Sudan it’s a known fact that the Acacia trees that grow and regenerate
naturally on their lands help improve soil fertility and crop yield if left as fallow for
some years before cultivating it again. During fallow the A. senegal and A. seyal trees
can be tapped for gum Arabic, a resin used in food, beverages as well as for industrial
purposes, as an extra source of income. This so called bush fallow system is
commonly used in Sahel, but droughts during recent decades has caused many
farmers to shorten the period of fallow as the need for more arable land increased. The
removal of vegetation, in turn, makes the land susceptible to erosion and degradation
and the need for even more land rises as nutrients are lost. At the same time, the
drylands in Africa are seen as an underexplored potential sink of atmospheric carbon
dioxide.
In this study two neighbouring villages with different land use focus are compared;
one with emphasis on gum production and the preservation of the trees and the other
with a greater focus on producing cash crops. The objectives are to see if there is a
difference in the soil properties between the two and if this in turn can be linked to the
biomass consumption and the land management in general. As a final step it evaluates
the stability of these strategies and tries to make some projections for the future. To
achieve these goals soil samples were collected, standing biomass stock was measured
and calculated and interviews regarding household biomass consumption and land use
history were held in each village.
Contrary to what could be expected, the results do not show one village having overall
better soil properties than the other, with the most likely reason for this being that the
villages chosen quite simply are not as different as anticipated. In both villages, the
present annual biomass consumption does not exceed the production and the biggest
concern for the future is access to drinking water. The lack of water is presented as the
main reason for seasonal migration from the villages and it is likely to increase if the
temperature rises and rainfall decreases. (Less)
Please use this url to cite or link to this publication:
author
Thorstensson, Helen
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
biomass, agroforestry, Sudan, semiarid, physical geography, acacia senegal, geography, gum arabic, nutrients
publication/series
Lunds universitets Naturgeografiska institution - Seminarieuppsatser
report number
168
funder
SIDA, Minor Field Study programme (MFS)
language
English
additional info
Bashir Awad El Tahir, Agricultural Research Cooperation, El Obeid.
id
1859052
date added to LUP
2011-04-14 11:04:39
date last changed
2011-12-19 11:52:23
@misc{1859052,
  abstract     = {In rural Sudan, as in many parts of Africa, biomass is the most important source of
energy. Besides the use as fuelwood for cooking and heating of houses, biomass is
also used for construction of houses and fences amongst other things. Among farmers
in semiarid Sudan it’s a known fact that the Acacia trees that grow and regenerate
naturally on their lands help improve soil fertility and crop yield if left as fallow for
some years before cultivating it again. During fallow the A. senegal and A. seyal trees
can be tapped for gum Arabic, a resin used in food, beverages as well as for industrial
purposes, as an extra source of income. This so called bush fallow system is
commonly used in Sahel, but droughts during recent decades has caused many
farmers to shorten the period of fallow as the need for more arable land increased. The
removal of vegetation, in turn, makes the land susceptible to erosion and degradation
and the need for even more land rises as nutrients are lost. At the same time, the
drylands in Africa are seen as an underexplored potential sink of atmospheric carbon
dioxide.
In this study two neighbouring villages with different land use focus are compared;
one with emphasis on gum production and the preservation of the trees and the other
with a greater focus on producing cash crops. The objectives are to see if there is a
difference in the soil properties between the two and if this in turn can be linked to the
biomass consumption and the land management in general. As a final step it evaluates
the stability of these strategies and tries to make some projections for the future. To
achieve these goals soil samples were collected, standing biomass stock was measured
and calculated and interviews regarding household biomass consumption and land use
history were held in each village.
Contrary to what could be expected, the results do not show one village having overall
better soil properties than the other, with the most likely reason for this being that the
villages chosen quite simply are not as different as anticipated. In both villages, the
present annual biomass consumption does not exceed the production and the biggest
concern for the future is access to drinking water. The lack of water is presented as the
main reason for seasonal migration from the villages and it is likely to increase if the
temperature rises and rainfall decreases.},
  author       = {Thorstensson, Helen},
  keyword      = {biomass,agroforestry,Sudan,semiarid,physical geography,acacia senegal,geography,gum arabic,nutrients},
  language     = {eng},
  note         = {Student Paper},
  series       = {Lunds universitets Naturgeografiska institution - Seminarieuppsatser},
  title        = {Relating soil properties to biomass consumption and land management in semiarid Sudan : a minor field study in North Kordofan},
  year         = {2009},
}