Agriculture: Dominant Relations
Agricultural demand (AGDEM) is an aggregation of food (FDEM), feed (FEDDEM), and industrial (INDEM) demand. Agricultural production (AGP) is a product of land (LD) and yield (YL) for crops and of size of livestock herd (LVHERF) for meat.
For causal diagrams see Agriculture - Agricultural Demand and Agriculture Production: Crops.
For equations see Agricultural Equations Demand and Agricultural Equations Supply.
Agriculture: Key Dynamics and Control Points
Key dynamics are directly linked to the dominant relations:
· Food demand depends on the GDP per capita and agricultural prices, computed endogenously. The user can control demand dynamics via an agricultural demand multiplier (agdemm) and the elasticity of crop demand with prices (elascd). Feed demand depends on the size of the livestock herd relative to grazing land capacity and will be strongly influenced by assumptions of the calories that a population derives from meat (calmeatm)
· The model user can control agricultural production directly with the yield multiplier, ylm. Rates of loss between gross production and market (LOSS) are determined endogenously, but can be controlled also by the user (lossm). Agricultural capital (AGP) underlying endogenous calculations of yield and developed crop land (LD) depend on endogenously determined, cost-responsive investment rates that the user can influence in the aggregate (via aginvm). Land depends also on exogenously specified multiplier on forests (forestm).
Agriculture: Selected Added Value
The larger food and agriculture model provides representation and control over agricultural trade and pricing. The model also has an open system for user-specified feedback between carbon dioxide build-up and crop yields. Further, there is representation of both ocean fish and aquaculture fish.