Modeling economics of carbon sequestration in
Tanzanian farm production systems
Asheim, L.J., Zabron, C.N., Mwaseba, D. and EIK, L.O.
SUA/Noragric/NILF
Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
SYNOPSIS
Production systems in Mgeta and Njombe
Challenges, problems and opportunities
Method
Progress farm modeling (Mgeta)
Further model development
Parameterization
Conclusion
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Production System in Mgeta
Vegetables in very steep slopes or terraces
Manual field work that can`t be mechanized
Two season cycles are important:
Rain:Sept.-May-270days & dry:Jun.-Aug.95days
Crop-livestock integrated production system
Dairy goats, >1500 of Norwegian breed
Pork, indigenous meat goats, and poultry
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Production System in Njombe
Manual field work – can be mechanized
Only one rain season (February-May)
More land with opportunities for forests
Crop-livestock dominant agricultural system
Dairy cows (Friesian, Ayshire, Jersey)
Pork, indigenous cows, goats, and poultry
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Challenges
Climate change, increased population, intensive
production systems, reduced land use,
competition for water, poverty and malnutrition!
Tasks: Examine economic and environmental
constraints at the farm level, identify and study farm
development paths
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Problems and opportunities (Mgeta)
Environmentally disastrous production system
Agricultural productivity can be increased:
Dairy goats and cows can milk more
Improved feeding
Improved veterinary services
Grass and multipurpose trees (MPPT) for:
Increased soil carbon sequestration
Management of erosion
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Method
Linear programming (LP) model to identify activities
with maximum objective function, not violate
constraints, no negative activity
Max Z = c’x, subject to Ax≤b, x≥0
Z = objective function, farm gross margin
 c’ = a vector of marginal activity gross margins
 x = a vector of activity levels
 A = a matrix of activity resource requirements
 b = a vector of resources e.g land, work h
 Built in Excel, price level 2012, assumed certainty
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NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Norwegian Agr. Econ. Research Instituet (NILF
Sokoine University of Agriculture (SUA)
Mgeta
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Activities (Mgeta)
Cropping homestead land (0.28 ha):
Tomatoes, potatoes, cabbage, both seasons
N-fixing: beans, green peas, both seasons
Grass, MPPT, permanent
Cropping distant farm land (0.34 ha):
Beans and maize, both seasons
Grass and MPPT, permanent (haymaking)
Both areas: Fruit trees in between
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Activities cont.
Communal land: Grass and MPPT
Feed purchase: Maize bran in both seasons
Animals:
Dairy goats, for milk sale or self-sufficiency
Meat goats or pork for meat and manure
Laying hens for self-sufficiency
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Activities cont.
Using mineral fertilizers and manure for crops
Adding cost of land maintenance
Hiring workers, dry and rain season
Consuming vegetable, dry and rain season
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NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Norwegian Agr. Econ. Research Instituet (NILF)
Sokoine University of Agriculture (SUA)
Terracing and land maintenance
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Resources
Categories of land according to season
Allowable number of fruit trees/ha
Allowable amounts of communal land feed
Mineral fertilizer < purchased amounts
Manure use < farm produced + purchased
Intercropping:
 Potatoes < green peas in both seasons
 Maize < beans in both seasons
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Resources
Energy in feed (MJ) < produced each season
Protein in feed (kg AAT) < produced each season
Work < available time + hired each season
Family energy need (MJ) < produced each season
Protein need (kg) < produced each season
Vegetable consumed < produced amounts each
season
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Further model development
Options for increased soil C sequestration:
Limit vegetable crops (e.g. only for family)
Increase grass & MPPT (e.g. 50% of area)
More purchased feed adding more manure to soils
Is less feeding of crop residues efficient for C
sequestration?
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Model development: cont.
Policy instruments:
subsidies for feed purchase,
investment support in yoghurt production
payment for permanent grassland & MPPT
support for purchase of mineral fertilizers
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Model parameterization
Mgeta model based on questionnaire to farmers
(Cuthibert N. Zabron)
Njombe questionnaire (Nina Lande)
Other areas (Haydom) and techniques (CA)
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Norwegian Agricultural Economics Research Institute (NILF)
Sokoine University of Agriculture (SUA)
NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Conclusion
In Mgeta we basically end up with a study of
economics of a changeover from vegetable crop
systems to specialized dairy goat and more permant
grass systems with MPPT
Njombe has not come so far, but it will be dairy cows
instead of goats and forest planting for C
sequestration is an issue
Other areas (Haydom) and techniques (CA) is not
decided yet
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NORWEGIAN UNIVERSITY OF LIFE SCIENCES
Norwegian Agr. Econ. Research Instituet (NILF
Sokoine University of Agriculture (SUA)
Thanks for listening
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