Presentation from the CCAFS Farm-household Modeling workshop - Amsterdam, 23-35 April 2012

1. An integrated simulation
model for assessing
smallholder crop-
livestock production
(in Yucatán, Mexico)
David Parsons
TIAR – research • development • extension • education • training

2. Short model description
• Goal of model development
– Simulate Mexican sheep-maize systems including
very specific management decisions.
– Assess outcomes on biomass and nutrient cycling,
labor needs, and profitability.
• Example research questions addressed
– Enterprise specialization versus integration
– Trade-offs in allocation of manure to crops or
forages

3. The Integrated model
Vensim™
APSIM
Flock dynamics
Climate
Livestock feeding
Soil organic matter,
nutrient ,and water Nutrient allocations
dynamics Venlink
interface Management
Surface organic matter variables Labor
Plant growth Economics
Maize
Grass
Corral
SRNS data
Intake
Weight gain
Manure quantity
Manure quality

4. Developments needed to
better deal with this attribute
Which
Covered For
If ‘yes’, which indicators would
in household
Attribute indicators were you like to use For your model
previous level models
used? in future to deal
analyses? in general
with attribute?
Economic yes Returns to labor, unchanged none Endogenise
performance profitability at farmer
enterprise & HH behaviour
scale
Food self- in part Maize grain Other staple Additional crop Endogenise
sufficiency reserves, sheep crops, other and live stock farmer
(not relative to livestock enterprises behaviour
consumption)
Food security no Food storage Cash reserves More Endogenise
economics e.g. farmer
off-farm income behaviour

5. Developments needed to
better deal with this attribute
Covered Which indicators For
If ‘yes’, which
in would you like to household
Attribute indicators were For your model
previous use in future to level models
used?
analyses? deal with attribute? in general
Climate In part Effects on Same indicators, None Δs in
variability production & more explicit mean,
profitability analyses variance,
P[Extreme]
Risk No None Climate and price Capacity exists,
risks simulation time
an issue?
Mitigation No None (Not purpose of Emissions, HH & Life cycle
model) community analysis
level
(CC) No None Simple to add. Has capacity
Adaptation What-if scenarios

6. Final remarks
• Initial aims were to model a specific system, not
develop a generic model;
– Nor to address climate change issues
• However, these methods could be built on.
• Main strength is daily feedbacks between all system
components
• Also, icon-based display of Vensim aids thinking
• Weakness is amount of development needed to
model a new system