modelFood_Production
Food production
Information
This model describes the production of food. Food is a controlled variable, as farmers decide what to grow and how much to grow on the basis of their perception of what they can sell. Consequently, the model uses the perceived food ratio as a state variable. If the farmers decide that too much food is being produced already, they'll produce less next year, and vice versa.A second state variable describes the capital that is being invested in growing food. Since that capital (for example, the capital expended in buying food harvesting machines) cannot be allocated or freed instantaneously, it makes sense to maintain also that variable as a state variable.
The agricultural input is measured in dollars/year, whereas the food ratio is dimensionless.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | agr_inp_init | 5e9 | Initial agricultural input |
| Real | food_short_perc_del | 2 | Food shortage perception delay |
| Real | land_fr_harvested | 0.7 | Land fraction harvested |
| Real | p_avg_life_agr_inp_1 | 2 | Default average life of agricultural input |
| Real | p_avg_life_agr_inp_2 | 2 | Controlled average life of agricultural input |
| Real | p_land_yield_fact_1 | 1 | Default land yield factor |
| Real | perc_food_ratio_init | 1 | Initial perceived food ratio |
| Real | processing_loss | 0.1 | Processing loss |
| Real | subsist_food_pc | 230 | Available per capita food |
| Real | t_policy_year | 4000 | Year of policy change |
| Real | tech_dev_del_TDD | 20 | Technology development time |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | ind_out_pc | Per capita annual industrial output | |
| Modelica.Blocks.Interfaces.RealInput | industrial_output | Annual industrial output | |
| Modelica.Blocks.Interfaces.RealInput | fr_inp_al_land_dev | Fraction of capital invested in agriculture allocated to the devlopment of arable land | |
| Modelica.Blocks.Interfaces.RealInput | arable_land | Arable land | |
| Modelica.Blocks.Interfaces.RealOutput | marg_prod_agr_inp | Development of marginally producing land | |
| Modelica.Blocks.Interfaces.RealOutput | land_yield | Land yield | |
| Modelica.Blocks.Interfaces.RealInput | population | Population | |
| Modelica.Blocks.Interfaces.RealInput | yield_tech_LYTD | Technology induced absolute yield enhancement | |
| Modelica.Blocks.Interfaces.RealInput | land_fertility | Land fertility | |
| Modelica.Blocks.Interfaces.RealInput | s_yield_mlt_air_poll | Land yield multiplier from air pollution | |
| Modelica.Blocks.Interfaces.RealOutput | food_ratio | Food ratio | |
| Modelica.Blocks.Interfaces.RealOutput | tot_agric_invest | Total investment in the agricultural sector | |
| Modelica.Blocks.Interfaces.RealOutput | agr_inp_per_hect | Agricultural investments per hectare | |
| Modelica.Blocks.Interfaces.RealOutput | s_fioa_agr | Fraction of total investments allocated to the agricultural sector | |
| Modelica.Blocks.Interfaces.RealOutput | p_fr_inp_for_land_maint | Fraction of investments in the agricultural sector allocated to land maintenance | |
| Modelica.Blocks.Interfaces.RealOutput | yield_tech_mult_icor_COYM | Technology induced relative enhancement of land yield | |
| Modelica.Blocks.Interfaces.RealOutput | food_pc | Per capita annually consumed food |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Functions.Tabular | P_Indic_Food_PC_1 | p.286 of Dynamics of Growth in a Finite World | |
| Functions.Tabular | P_Indic_Food_PC_2 | p.286 of Dynamics of Growth in a Finite World | |
| Utilities.S_Indic_Food_PC | S_Indic_Food_PC | p.286 of Dynamics of Growth in a Finite World | |
| Functions.Tabular | P_Fr_IO_Al_Agr_1 | p.287 of Dynamics of Growth in a Finite World | |
| Modelica.Blocks.Math.Division | Div1 | ||
| Functions.Tabular | P_Fr_IO_Al_Agr_2 | p.287 of Dynamics of Growth in a Finite World | |
| Utilities.S_FIOA_Agr | S_FIOA_Agr | p.287 of Dynamics of Growth in a Finite World | |
| Auxiliary.Prod_2 | Tot_Agric_Invest | p.287 of Dynamics of Growth in a Finite World | |
| Sources.Source | Source1 | ||
| Rates.Rate_1 | Chg_Agr_Inp | ||
| Levels.Level1a | Agr_Inp | ||
| Utilities.Ch_Agr_Inp | Ch_Agr_Inp | p.292 of Dynamics of Growth in a Finite World | |
| Utilities.Current_Agr_Inp | Current_Agr_Inp | p.292 of Dynamics of Growth in a Finite World | |
| Utilities.S_Avg_Life_Agr_Inp | S_Avg_Life_Agr_Inp | p.293 of Dynamics of Growth in a Finite World | |
| Functions.Tabular | P_Fr_Inp_For_Land_Maint | p.332 of Dynamics of Growth in a Finite World | |
| Sources.Source | Source2 | ||
| Rates.Rate_1 | Chg_Perc_Food_Ratio | ||
| Levels.Level1a | Perc_Food_Ratio | ||
| Utilities.Agr_Inp_Per_Hect | Agr_Inp_Per_Hect | p.294 of Dynamics of Growth in a Finite World | |
| Functions.Tabular | Marg_Land_Yield_Mlt_Cap | p.313 of Dynamics of Growth in a Finite World | |
| Functions.Tabular | Land_Yield_Mlt_Cap | p.306 of Dynamics of Growth in a Finite World | |
| Auxiliary.Prod_4 | Land_Yield | p.307 of Dynamics of Growth in a Finite World | |
| Utilities.Marg_Prod_Agr_Inp | Marg_Prod_Agr_Inp | p.313 of Dynamics of Growth in a Finite World | |
| Utilities.Food | Food | p.280 of Dynamics of Growth in a Finite World | |
| Modelica.Blocks.Math.Division | Food_PC | p.281 of Dynamics of Growth in a Finite World | |
| Modelica.Blocks.Math.Gain | Food_Ratio | p.332 of Dynamics of Growth in a Finite World | |
| Utilities.Ch_Perc_Food_Ratio | Ch_Perc_Food_Ratio | p.333 of Dynamics of Growth in a Finite World | |
| Utilities.S_Land_Yield_Fact | S_Land_Yield_Fact | p.307 of Dynamics of Growth in a Finite World | |
| Functions.SMTH3 | P_Land_Yield_Fact_2 | ||
| Functions.Tabular | Yield_Tech_Mult_Icor_COYM |