blockFood_Production

Food production
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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

TypeNameDefaultDescription
Realagr_inp_init5000000000.0Initial agricultural input
Realfood_short_perc_del2Food shortage perception delay
Realland_fr_harvested0.7Land fraction harvested
Realp_avg_life_agr_inp_12Default average life of agricultural input
Realp_avg_life_agr_inp_22Controlled average life of agricultural input
Realp_land_yield_fact_11Default land yield factor
Realperc_food_ratio_init1Initial perceived food ratio
Realprocessing_loss0.1Processing loss
Realsubsist_food_pc230Available per capita food
Realt_policy_year4000Year of policy change
Realtech_dev_del_TDD20Technology development time

Connectors

TypeNameDefaultDescription
SystemDynamics.Interfaces.MassInPortind_out_pcPer capita annual industrial output
SystemDynamics.Interfaces.MassInPortindustrial_outputAnnual industrial output
SystemDynamics.Interfaces.MassInPortfr_inp_al_land_devFraction of capital invested in agriculture allocated to the devlopment of arable land
SystemDynamics.Interfaces.MassInPortarable_landArable land
SystemDynamics.Interfaces.MassOutPortmarg_prod_agr_inpDevelopment of marginally producing land
SystemDynamics.Interfaces.MassOutPortland_yieldLand yield
SystemDynamics.Interfaces.MassInPortpopulationPopulation
SystemDynamics.Interfaces.MassInPortyield_tech_LYTDTechnology induced absolute yield enhancement
SystemDynamics.Interfaces.MassInPortland_fertilityLand fertility
SystemDynamics.Interfaces.MassInPorts_yield_mlt_air_pollLand yield multiplier from air pollution
SystemDynamics.Interfaces.MassOutPortfood_ratioFood ratio
SystemDynamics.Interfaces.MassOutPorttot_agric_investTotal investment in the agricultural sector
SystemDynamics.Interfaces.MassOutPortagr_inp_per_hectAgricultural investments per hectare
SystemDynamics.Interfaces.MassOutPorts_fioa_agrFraction of total investments allocated to the agricultural sector
SystemDynamics.Interfaces.MassOutPortp_fr_inp_for_land_maintFraction of investments in the agricultural sector allocated to land maintenance
SystemDynamics.Interfaces.MassOutPortyield_tech_mult_icor_COYMTechnology induced relative enhancement of land yield
SystemDynamics.Interfaces.MassOutPortfood_pcPer capita annually consumed food

Components

TypeNameDefaultDescription
SystemDynamics.Functions.TabularP_Indic_Food_PC_1p.286 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.TabularP_Indic_Food_PC_2p.286 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.S_Indic_Food_PCS_Indic_Food_PCp.286 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.TabularP_Fr_IO_Al_Agr_1p.287 of Dynamics of Growth in a Finite World
Modelica.Blocks.Math.DivisionDiv1
SystemDynamics.Functions.TabularP_Fr_IO_Al_Agr_2p.287 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.S_FIOA_AgrS_FIOA_Agrp.287 of Dynamics of Growth in a Finite World
SystemDynamics.Auxiliary.Prod_2Tot_Agric_Investp.287 of Dynamics of Growth in a Finite World
SystemDynamics.Sources.SourceSource1
SystemDynamics.Rates.Rate_1Chg_Agr_Inp
SystemDynamics.Levels.Level1aAgr_Inp
SystemDynamics.WorldDynamics.World3.Utilities.Ch_Agr_InpCh_Agr_Inpp.292 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.Current_Agr_InpCurrent_Agr_Inpp.292 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.S_Avg_Life_Agr_InpS_Avg_Life_Agr_Inpp.293 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.TabularP_Fr_Inp_For_Land_Maintp.332 of Dynamics of Growth in a Finite World
SystemDynamics.Sources.SourceSource2
SystemDynamics.Rates.Rate_1Chg_Perc_Food_Ratio
SystemDynamics.Levels.Level1aPerc_Food_Ratio
SystemDynamics.WorldDynamics.World3.Utilities.Agr_Inp_Per_HectAgr_Inp_Per_Hectp.294 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.TabularMarg_Land_Yield_Mlt_Capp.313 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.TabularLand_Yield_Mlt_Capp.306 of Dynamics of Growth in a Finite World
SystemDynamics.Auxiliary.Prod_4Land_Yieldp.307 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.Marg_Prod_Agr_InpMarg_Prod_Agr_Inpp.313 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.FoodFoodp.280 of Dynamics of Growth in a Finite World
Modelica.Blocks.Math.DivisionFood_PCp.281 of Dynamics of Growth in a Finite World
Modelica.Blocks.Math.GainFood_Ratiop.332 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.Ch_Perc_Food_RatioCh_Perc_Food_Ratiop.333 of Dynamics of Growth in a Finite World
SystemDynamics.WorldDynamics.World3.Utilities.S_Land_Yield_FactS_Land_Yield_Factp.307 of Dynamics of Growth in a Finite World
SystemDynamics.Functions.SMTH3P_Land_Yield_Fact_2
SystemDynamics.Functions.TabularYield_Tech_Mult_Icor_COYM