Agriculture - Revision history

Yutang.Xiong at 03:26, 23 January 2026

2026-01-23T03:26:26Z

← Older revision		Revision as of 03:26, 23 January 2026
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	Losses can occur at several places along the chain from production. In earlier sections, we mentioned losses at the production stage. Losses can also occur in the process of transmission and distribution from the producer to the final consumer and at the consumer stage. The latter is sometimes referred to as food waste, but for our purposes, we will use the term loss for all three stages: production, transmission and distribution, and consumption.		Losses can occur at several places along the chain from production. In earlier sections, we mentioned losses at the production stage. Losses can also occur in the process of transmission and distribution from the producer to the final consumer and at the consumer stage. The latter is sometimes referred to as food waste, but for our purposes, we will use the term loss for all three stages: production, transmission and distribution, and consumption.

	The FAO Food Balance Sheets provide data on losses during transmission and distribution, but not at the production or consumption stages. Until we are able to find data showing a clear relationship between these losses and GDP per capita, or some other explanatory factor, we make an assumption of production losses and consumption losses of 10% for all countries. The user can make changes in these values with the parameters '''aglossprodperc'''and'''aglossconsperc'''respectively. The former can be set for crops, meat, wild catch, and aquaculture separately. The latter combines wild catch and aquaculture as fish, as we do not have separate data on the consumption of wild caught versus farmed fish. More details on the use of these parameters and the actual calculation of production and consumption losses are provided in sections 3.1.1-3.1.3 and 3.2.1, respectively.		The FAO Food Balance Sheets provide data on losses during transmission and distribution, but not at the production or consumption stages. Until we are able to find data showing a clear relationship between these losses and GDP per capita, or some other explanatory factor, we make an assumption of production losses and consumption losses of 10% for all countries. The user can make changes in these values with the parameters '''aglossprodperc''' and '''aglossconsperc''' respectively. The former can be set for crops, meat, wild catch, and aquaculture separately. The latter combines wild catch and aquaculture as fish, as we do not have separate data on the consumption of wild caught versus farmed fish. More details on the use of these parameters and the actual calculation of production and consumption losses are provided in sections 3.1.1-3.1.3 and 3.2.1, respectively.

	Turning to transmission and distribution losses, some agricultural commodities will never make it from the producer to the final consumer because of pests, spoilage, etc.  The FAO food balance sheets provide data on food lost to waste for crops and meat , but not for fish. Thus, for now we assume that there are no losses in this stage for fish. For crops and meat, though we were able to establish relationships between transmission and distribution losses and GDP per capita. These are shown in the figures below:		Turning to transmission and distribution losses, some agricultural commodities will never make it from the producer to the final consumer because of pests, spoilage, etc.  The FAO food balance sheets provide data on food lost to waste for crops and meat , but not for fish. Thus, for now we assume that there are no losses in this stage for fish. For crops and meat, though we were able to establish relationships between transmission and distribution losses and GDP per capita. These are shown in the figures below:

Victoria.Pepera at 18:15, 8 January 2026

2026-01-08T18:15:49Z

← Older revision		Revision as of 18:15, 8 January 2026
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	<span style="font-family:arial,helvetica,sans-serif;">Please cite as: Dale S. Rothman, Hughes, Barry B., and Kanishka Narayan. 2017. ''"IFs Agriculture Model Documentation." ''Working paper 2017.07.04. Pardee Center for International Futures, Josef Korbel School of International Studies, University of Denver, Denver, CO. Accessed DD Month YYYY <[https://~~pardee~~.du.edu/~~wiki/Agriculture https://pardee.du~~.~~edu/wiki/~~Agriculture]></span>		<span style="font-family:arial,helvetica,sans-serif;">Please cite as: Dale S. Rothman, Hughes, Barry B., and Kanishka Narayan. 2017. ''"IFs Agriculture Model Documentation." ''Working paper 2017.07.04. Pardee Center for International Futures, Josef Korbel School of International Studies, University of Denver, Denver, CO. Accessed DD Month YYYY <[https://pardeewiki.du.edu/index.php?title=Agriculture]></span>

	The IFs agricultural model tracks the supply and demand, including imports, exports, and prices, of three agricultural commodities: crops, meat, and fish. Crops, meat and fish have direct food, animal feed, industrial and food manufactu<span style="font-family:arial,helvetica,sans-serif;">ring</span> uses. The agricultural model is also where land use dynamics and water use are tracked in IFs, as these are key resources for the agricultural sector.		The IFs agricultural model tracks the supply and demand, including imports, exports, and prices, of three agricultural commodities: crops, meat, and fish. Crops, meat and fish have direct food, animal feed, industrial and food manufactu<span style="font-family:arial,helvetica,sans-serif;">ring</span> uses. The agricultural model is also where land use dynamics and water use are tracked in IFs, as these are key resources for the agricultural sector.

Ryan.Power: changed =< to =<

2024-05-14T22:32:59Z

changed =< to =<

← Older revision		Revision as of 22:32, 14 May 2024
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	Two final checks are made on the value of IALK. First, it is not allowed to exceed a value related to the cost of replacing depreciated investment in land and bringing a portion of grazing or forested land into production.		Two final checks are made on the value of IALK. First, it is not allowed to exceed a value related to the cost of replacing depreciated investment in land and bringing a portion of grazing or forested land into production.

	<math>IALK_{r,t+1} =<((0.04* LD_{r,l=3} +0.04* LD_{r,l=4} +dkl* LD_{r,l=1} )* CLD_{r})/ IAval_{r} </math>		<math>IALK_{r,t+1} =< ((0.04* LD_{r,l=3} +0.04* LD_{r,l=4} +dkl* LD_{r,l=1} )* CLD_{r})/ IAval_{r} </math>

	Second, IALK is bound between 0.1 and 0.8.		Second, IALK is bound between 0.1 and 0.8.

Ryan.Power: removed more unicode

2024-05-14T22:31:03Z

removed more unicode

← Older revision	Revision as of 22:31, 14 May 2024
(No difference)

Ryan.Power: replaced sum with \sum

2024-05-14T21:54:27Z

replaced sum with \sum

← Older revision		Revision as of 21:54, 14 May 2024
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	At this point, the global sum of exports and imports across countries will likely differ. Therefore, a procedure is required to balance these. In preparation for this one more global variable and several country-level variables are calculated. The global variable is globalsurdefrate, which is the ratio of the sum across countries of net surplus divided by the sum across countries of demand and production, which is the stock base.		At this point, the global sum of exports and imports across countries will likely differ. Therefore, a procedure is required to balance these. In preparation for this one more global variable and several country-level variables are calculated. The global variable is globalsurdefrate, which is the ratio of the sum across countries of net surplus divided by the sum across countries of demand and production, which is the stock base.

	<math>globalsurdefrate_{f=1-3} =(sum_r(surpdef_{r,f=1-3} )/(sum_r(AGDEM_{r,f=1-3} + AGP_{r,f=1-3}))</math>		<math>globalsurdefrate_{f=1-3} =(\sum_r(surpdef_{r,f=1-3} )/(\sum_r(AGDEM_{r,f=1-3} + AGP_{r,f=1-3}))</math>

	The country-level variables are as follows:		The country-level variables are as follows:
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	This process may not fully reconcile global trade, so a final adjustment is made by setting world trade (WT) as the average of global exports and imports and then adjusting the country values accordingly:		This process may not fully reconcile global trade, so a final adjustment is made by setting world trade (WT) as the average of global exports and imports and then adjusting the country values accordingly:

	<math>WT_{f=1-3} =(sum_r(AGX_{r,f=1-3}) +sum_r(AGM_{r,f=1-3}) )/2</math> <math> AGX_{r,f=1-3} = AGX_{r,f=1-3} * WT_{f=1-3}/(sum_r(AGX_{r,f=1-3}) )</math> <math> AGM_{r,f=1-3} = AGM_{r,f=1-3} * WT_{f=1-3}/(sum_r(AGM_{r,f=1-3}) )</math>		<math>WT_{f=1-3} =(\sum_r(AGX_{r,f=1-3}) +\sum_r(AGM_{r,f=1-3}) )/2</math> <math> AGX_{r,f=1-3} = AGX_{r,f=1-3} * WT_{f=1-3}/(\sum_r(AGX_{r,f=1-3}) )</math> <math> AGM_{r,f=1-3} = AGM_{r,f=1-3} * WT_{f=1-3}/(\sum_r(AGM_{r,f=1-3}) )</math>

	IFs can now update the moving average export (XKAVE) and import (MKAVE) propensities for the next time step. The weights given to history are set by the global parameters '''xhw'''and '''mhw'''. For small exporters, i.e., where exports are less than one tenth of the sum of production and demand, '''xhw'''is reduced by 40 percent, allowing for faster adjustment. XKAVE and MKAVE are updated as		IFs can now update the moving average export (XKAVE) and import (MKAVE) propensities for the next time step. The weights given to history are set by the global parameters '''xhw'''and '''mhw'''. For small exporters, i.e., where exports are less than one tenth of the sum of production and demand, '''xhw'''is reduced by 40 percent, allowing for faster adjustment. XKAVE and MKAVE are updated as
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	The world price indices for crops and meat are computed, in the following year, as a weighted average of the domestic prices, with the weights given by crop and meat production:		The world price indices for crops and meat are computed, in the following year, as a weighted average of the domestic prices, with the weights given by crop and meat production:

	<math>WAP_{r,f=1-2,t+1} =(sum_r(FPRI_{r,f=1-2,t+1} * AGP_{r,f=1-2,t+1} ) )/(sum_r(AGP_{r,f=1-2,t+1}) )</math>		<math>WAP_{r,f=1-2,t+1} =(\sum_r(FPRI_{r,f=1-2,t+1} * AGP_{r,f=1-2,t+1} ) )/(\sum_r(AGP_{r,f=1-2,t+1}) )</math>

	== Returns and Profits ==		== Returns and Profits ==
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	<math>TInAg_{r,t} = INAG_{r,t-1}/GDP_{r,t-1} * GDP_{r,t}* WAgDemRMul_{t} * MulWSt_{t}* MulSt_{r,t}</math>		<math>TInAg_{r,t} = INAG_{r,t-1}/GDP_{r,t-1} * GDP_{r,t}* WAgDemRMul_{t} * MulWSt_{t}* MulSt_{r,t}</math>

	where, <math> WAgDemRMul_{t} =((~~sum_R~~(AGDEM_{r,t} )/WGDP_{t} )/((~~sum_R~~(AGDEM_{r,t-1})/WGDP_{t-1})</math>		where, <math> WAgDemRMul_{t} =((\sum_r(AGDEM_{r,t} )/WGDP_{t} )/((\sum_r(AGDEM_{r,t-1})/WGDP_{t-1})</math>

	To elaborate, MulWSt and MulSt are adjustment factors related to global and domestic crop stocks, respectively. Both use the PID ADJSTR function described earlier, just as changes in prices use it in order to set prices that change year-to-year so as to chase supply-demand equilibration over time. For MulWSt, the controlling parameters in the PID function for stocks versus targets and changes in stocks are hard coded with values of -0.3 and -0.9, respectively. For MulSt, these parameters are hard coded with values of -0.2 and -0.4, respectively.		To elaborate, MulWSt and MulSt are adjustment factors related to global and domestic crop stocks, respectively. Both use the PID ADJSTR function described earlier, just as changes in prices use it in order to set prices that change year-to-year so as to chase supply-demand equilibration over time. For MulWSt, the controlling parameters in the PID function for stocks versus targets and changes in stocks are hard coded with values of -0.3 and -0.9, respectively. For MulSt, these parameters are hard coded with values of -0.2 and -0.4, respectively.
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	Gross production (ZS) in the agricultural sector illustrates this procedure. The value of gross production in the agricultural model is the sum of the products of agricultural production (AGP) and prices (WAP) in each agricultural category. Multiplying that times an adjustment factor (ZSF) computed in the first time stop to assure inter-model consistency produces gross production for the economic (ZS). World average prices (WAP) are used in all the economic/physical model conversions because they assure that global sums (e.g. of exports and imports) will balance.<ref>s in the subscript represents economic sector. s = 1 is defined as the agriculture sector.</ref>		Gross production (ZS) in the agricultural sector illustrates this procedure. The value of gross production in the agricultural model is the sum of the products of agricultural production (AGP) and prices (WAP) in each agricultural category. Multiplying that times an adjustment factor (ZSF) computed in the first time stop to assure inter-model consistency produces gross production for the economic (ZS). World average prices (WAP) are used in all the economic/physical model conversions because they assure that global sums (e.g. of exports and imports) will balance.<ref>s in the subscript represents economic sector. s = 1 is defined as the agriculture sector.</ref>

	<math>ZS_{r,s=1}=ZSF_{r}sum_f(WAP_{f,t=1}AGP_{r,f,t} ) </math>		<math>ZS_{r,s=1}=ZSF_{r}\sum_f(WAP_{f,t=1}AGP_{r,f,t} ) </math>

	'''Where,'''		'''Where,'''

	<math>ZSF_{r} =ZS_{r,s=1}/(sum_f(WAP_{f,t=1}*AGP_{r,f,t=1} ) )</math>		<math>ZSF_{r} =ZS_{r,s=1}/(\sum_f(WAP_{f,t=1}*AGP_{r,f,t=1} ) )</math>

	Similarly, food stocks in each category (FSTOCK) and an adjustment factor (FSF) produce stocks (ST) for the economic model.		Similarly, food stocks in each category (FSTOCK) and an adjustment factor (FSF) produce stocks (ST) for the economic model.

	<math>ST_{r,s=1}=FSF_{r}sum_{f}(FSTOCK_{r,f,t} WAP_{f,t=1} ) </math>		<math>ST_{r,s=1}=FSF_{r}\sum_{f}(FSTOCK_{r,f,t} WAP_{f,t=1} ) </math>

	'''Where,'''		'''Where,'''

	<math>FSF_{r} = ST_{r,s=1}/(sum_{f}(FSTOCK_{r,f,t=1}* WAP_{f,t=1} ) )</math>		<math>FSF_{r} = ST_{r,s=1}/(\sum_{f}(FSTOCK_{r,f,t=1}* WAP_{f,t=1} ) )</math>

	A similar translation is made for consumer spending on agricultural commodities, recognizing that not all crop demand is directly by consumers.		A similar translation is made for consumer spending on agricultural commodities, recognizing that not all crop demand is directly by consumers.

	<math>CS_{r,s=1} = CSF_{r} (FDEM_{r,t} WAP_{f=1,t=1} +sum_{f=2,3}(AGDEM_{r,f,t}* WAP_{f,t=1} ) )</math>		<math>CS_{r,s=1} = CSF_{r} (FDEM_{r,t} WAP_{f=1,t=1} +\sum_{f=2,3}(AGDEM_{r,f,t}* WAP_{f,t=1} ) )</math>

	'''Where'''		'''Where'''

	<math>CSF_{r} = CS_{r,s=1} /(FDEM_{r,t=1}* WAP_{f=1,t=1} +sum_{f=2,3}(AGDEM_{r,f,t}* WAP_{f,t=1} ) )</math>		<math>CSF_{r} = CS_{r,s=1} /(FDEM_{r,t=1}* WAP_{f=1,t=1} +\sum_{f=2,3}(AGDEM_{r,f,t}* WAP_{f,t=1} ) )</math>

	In the same fashion exports (AGX) and imports (AGM) from the agricultural model allow calculation of exports (XS) and imports (MS) for the economic model.		In the same fashion exports (AGX) and imports (AGM) from the agricultural model allow calculation of exports (XS) and imports (MS) for the economic model.

	<math>XS_{r,s=1}= xsf_{r} sum_f(AGX_{r,f,t} WAP_{f,t=1} ) </math>		<math>XS_{r,s=1}= xsf_{r} \sum_f(AGX_{r,f,t} WAP_{f,t=1} ) </math>

	'''Where'''		'''Where'''

	<math>xsf_{r}= XS_{r,s=1}/(sum_{f}(AGX_{r,f,t=1}* WAP_{f,t=1} ) )</math>		<math>xsf_{r}= XS_{r,s=1}/(\sum_{f}(AGX_{r,f,t=1}* WAP_{f,t=1} ) )</math>

	and		and

	<math>MS_{r,s=1} = msf_{r} sum_f(AGX_{r,f,t} WAP_{f,t=1} ) </math>		<math>MS_{r,s=1} = msf_{r} \sum_f(AGX_{r,f,t} WAP_{f,t=1} ) </math>

	'''where'''		'''where'''

	<math>msf_{r}= MS_{r,s=1}/(sum_f(AGN_{r,f,t}* WAP_{f,t=1} ) )</math>		<math>msf_{r}= MS_{r,s=1}/(\sum_f(AGN_{r,f,t}* WAP_{f,t=1} ) )</math>

	A check and, if necessary, adjustment is made ensure that the monetary values of imports and exports match up at the global level.		A check and, if necessary, adjustment is made ensure that the monetary values of imports and exports match up at the global level.

	<math>XS_{r,s=1} = XS_{r,s=1} * ((sum_{r}(XS_{r,s=1} ) +sum_{r}(MS_{r,s=1} ) )/2)/(sum_{r}(XS_{r,s=1} ) )</math>		<math>XS_{r,s=1} = XS_{r,s=1} * ((\sum_{r}(XS_{r,s=1} ) +\sum_{r}(MS_{r,s=1} ) )/2)/(\sum_{r}(XS_{r,s=1} ) )</math>

	and		and

	<math>MS_{r,s=1}= MS_{r,s=1} *((sum_{r}(XS_{r,s=1} ) +sum_r(MS_{r,s=1} ) )/2)/(sum_{r}(MS_{r,s=1} ) )</math>		<math>MS_{r,s=1}= MS_{r,s=1} *((\sum_{r}(XS_{r,s=1} ) +\sum_r(MS_{r,s=1} ) )/2)/(\sum_{r}(MS_{r,s=1} ) )</math>

	With respect to prices, the agriculture model passes to the economic model a value (PRI), which reflects the ratio of the current domestic crop price index to the initial world crop price index.		With respect to prices, the agriculture model passes to the economic model a value (PRI), which reflects the ratio of the current domestic crop price index to the initial world crop price index.
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	'''where,'''		'''where,'''

	<math>NonUrbanShr_{r,t=1,t} =(sum_{l}LD_{r,l=1-4,t} )/(sum_{l}LD_{r,l=1-5,t} )</math>		<math>NonUrbanShr_{r,t=1,t} =(\sum_{l}LD_{r,l=1-4,t} )/(\sum_{l}LD_{r,l=1-5,t} )</math>

	Second, if urban land is declining, it is not permitted to fall below 10,000 hectares. Third, the changes in Urban land are assumed to affect all other land categories proportionately		Second, if urban land is declining, it is not permitted to fall below 10,000 hectares. Third, the changes in Urban land are assumed to affect all other land categories proportionately

	<math>Reduc_{r,l=1-4} = NUrbLD_{r} * LD_{r,l=1-4}/(sum_{l}LD_{r,l=1-4} )</math>		<math>Reduc_{r,l=1-4} = NUrbLD_{r} * LD_{r,l=1-4}/(\sum_{l}LD_{r,l=1-4} )</math>

	However, this is not allowed to result in the area for a given land category falling below 1,000 hectares. Thus, there may be a slight reduction in the amount of new urban land in certain cases.		However, this is not allowed to result in the area for a given land category falling below 1,000 hectares. Thus, there may be a slight reduction in the amount of new urban land in certain cases.
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	Two final adjustments are made to the land area values to clean up any quirks that might have be introduced in the previous processes. First, the values for each category are bound between one thousand and ten billion hectares. Second, the values are normalized so that the sum of the categories equals the total amount of land.		Two final adjustments are made to the land area values to clean up any quirks that might have be introduced in the previous processes. First, the values for each category are bound between one thousand and ten billion hectares. Second, the values are normalized so that the sum of the categories equals the total amount of land.

	<math>[LD]_{r,l=1-5,t+1}=LD{r,l=1-5} * LD_{r,l=1-5}/(sum_{l}LD_{r,l=1-5} )</math>		<math>[LD]_{r,l=1-5,t+1}=LD{r,l=1-5} * LD_{r,l=1-5}/(\sum_{l}LD_{r,l=1-5} )</math>

	Finally, a value for world forest area (WFORST) is calculated at the end of this process by summing forestland area across all countries.		Finally, a value for world forest area (WFORST) is calculated at the end of this process by summing forestland area across all countries.

	<math>WFORST_{t+1}=sum_{l}LD_{r,l=3} </math>		<math>WFORST_{t+1}=\sum_{l}LD_{r,l=3} </math>

	== Livestock Dynamics ==		== Livestock Dynamics ==

Ryan.Power: fixed some broken unicode

2024-05-14T00:12:46Z

fixed some broken unicode

← Older revision		Revision as of 00:12, 14 May 2024
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	The maximum possible yield (YLLim) is estimated for each country and can change over time.  It is calculated as the maximum of 1.5 times the initial yield (YL<sub>r,t=1</sub>) and the multiple of an external user-controlled parameter ('''''ylmax''''') and an adjustment factor (YLMaxM).		The maximum possible yield (YLLim) is estimated for each country and can change over time.  It is calculated as the maximum of 1.5 times the initial yield (YL<sub>r,t=1</sub>) and the multiple of an external user-controlled parameter ('''''ylmax''''') and an adjustment factor (YLMaxM).

	<math>YLLim_{r} = max(ylmax_{r}* YLMaxM_{r}, 1.5* YL_{r,t=1})</math>		<math>YLLim_{r} = max (ylmax_{r}* YLMaxM_{r}, 1.5* YL_{r,t=1})</math>

	where,		where,
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	The effect of changes in annual average temperature and precipitation are based upon two assumptions: 1) there is an optimal temperature (Topt) for crop growth, with yields falling both below and above this temperature and 2) there is a logarithmic relationship between precipitation and crop yields.  The choice of this functional form was informed by work reviewed in Cline (2007)<ref>Cline, William R. 2007. Global warming and agriculture: Impact estimates by country. Washington, DC: Peterson Institute for International Economics.</ref>.  Together, these result in the following equation:		The effect of changes in annual average temperature and precipitation are based upon two assumptions: 1) there is an optimal temperature (Topt) for crop growth, with yields falling both below and above this temperature and 2) there is a logarithmic relationship between precipitation and crop yields.  The choice of this functional form was informed by work reviewed in Cline (2007)<ref>Cline, William R. 2007. Global warming and agriculture: Impact estimates by country. Washington, DC: Peterson Institute for International Economics.</ref>.  Together, these result in the following equation:

	<math>ClimateEffect_{t+1} = 100{({e^{(-0.5(T0_{r}+ DeltaT{r} - Topt)^2)/SigmaTsqd}ln(P0_{r}(DeltaP_{r}/100+1))/e^{(-0.5(T0_{r}-Topt)^2/SigmaTsqd}ln(P0_r))-1}} </math>		<math>ClimateEffect_{t+1} = 100{({e^{(-0.5(T0_{r}+ DeltaT{r} - Topt)^2)/SigmaTsqd}ln(P0_{r}(DeltaP_{r}/100+1))/e^{(-0.5(T0_{r}-Topt)^2/SigmaTsqd}ln (P0_r))-1}} </math>

	where,		where,
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	In the forecast years, FDEM is initially calculated based upon the calculation of daily grams per capita described in this section below:		In the forecast years, FDEM is initially calculated based upon the calculation of daily grams per capita described in this section below:

	<math>FDEM_{r,f=1-3} = GRAMSPC_{r,f=1-3} * POP_{r}* 365/100000 </math>		<math>FDEM_{r,f=1-3} = GRAMSPC_{r,f=1-3} * POP_{r}* 365/100000</math>

	There are two situations where the value of FDEM might be adjusted. The first case is where more than 85 percent of consumers’ expenditures are on food stuffs. If this is the case, the values of FDEM for crops and meat and fish are reduced proportionately, as described in this section below.		There are two situations where the value of FDEM might be adjusted. The first case is where more than 85 percent of consumers’ expenditures are on food stuffs. If this is the case, the values of FDEM for crops and meat and fish are reduced proportionately, as described in this section below.

Wikiadmin at 17:24, 7 September 2018

2018-09-07T17:24:17Z

← Older revision		Revision as of 17:24, 7 September 2018
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	#AGDOMSUPP = AGP + AGM – AGX. This says that total domestic supply equals production plus imports minus exports. This equivalence can be broken if there are changes in stocks, which we will see in forecast years. Currently, however, we assume there are no such changes in the first year. Thus it may be necessary to make adjustment for the equivalence to hold in first year. This is done in the pre-processor, by keeping AGDOMSUPP the same and applying the following three rules:<ol style="list-style-type:lower-alpha;">		#AGDOMSUPP = AGP + AGM – AGX. This says that total domestic supply equals production plus imports minus exports. This equivalence can be broken if there are changes in stocks, which we will see in forecast years. Currently, however, we assume there are no such changes in the first year. Thus it may be necessary to make adjustment for the equivalence to hold in first year. This is done in the pre-processor, by keeping AGDOMSUPP the same and applying the following three rules:<ol style="list-style-type:lower-alpha;">
	~~</ol></ol>~~

	*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.		*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.

Wikiadmin at 17:19, 7 September 2018

2018-09-07T17:19:27Z

← Older revision		Revision as of 17:19, 7 September 2018
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	\|}		\|}

	~~  ~~

	~~ ~~

	~~ ~~

	== Trade ==		== Trade ==

Wikiadmin at 17:17, 7 September 2018

2018-09-07T17:17:21Z

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	\|-		\|-
	\| ~~<div>~~		\|
	'''Box 1: Adjustments in the Pre-processor to Ensure Proper Balances'''		'''Box 1: Adjustments in the Pre-processor to Ensure Proper Balances'''

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	#AGDOMSUPP = AGP + AGM – AGX. This says that total domestic supply equals production plus imports minus exports. This equivalence can be broken if there are changes in stocks, which we will see in forecast years. Currently, however, we assume there are no such changes in the first year. Thus it may be necessary to make adjustment for the equivalence to hold in first year. This is done in the pre-processor, by keeping AGDOMSUPP the same and applying the following three rules:<ol style="list-style-type:lower-alpha;">		#AGDOMSUPP = AGP + AGM – AGX. This says that total domestic supply equals production plus imports minus exports. This equivalence can be broken if there are changes in stocks, which we will see in forecast years. Currently, however, we assume there are no such changes in the first year. Thus it may be necessary to make adjustment for the equivalence to hold in first year. This is done in the pre-processor, by keeping AGDOMSUPP the same and applying the following three rules:<ol style="list-style-type:lower-alpha;">
	</ol></ol>		</ol></ol>
	~~</ol>~~
	~~</ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol>~~

	*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.		*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.
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	*AGP + AGM – AGX = FDEM + FEDEM + INDEM + FMDEM + AGLOSSTRANS. This says that the total domestic supply, which accounts for production losses, has to match the total uses (including losses in transmission and distribution).		*AGP + AGM – AGX = FDEM + FEDEM + INDEM + FMDEM + AGLOSSTRANS. This says that the total domestic supply, which accounts for production losses, has to match the total uses (including losses in transmission and distribution).

	&~~lt;/ol&gt~~;		The pre-processor includes procedures to ensure that these three conditions hold for the initial values in each country. This can lead to minor adjustments in the values for the supply and demand categories. These processes can also lead to changes in related variables, including the production of non-animal meat products (CAGPMILKEGGS), fish catch (AGFISHCATCH), aquaculture production (AQUACUL), the size of the livestock herd (LVHERD), and the breakdown of land areas (LD). The latter occurs because we do not want these processes to change crop yields (YL).

	The pre-processor includes procedures to ensure that these three conditions hold for the initial values in each country. This can lead to minor adjustments in the values for the supply and demand categories. These processes can also lead to changes in related variables, including the production of non-animal meat products (CAGPMILKEGGS), fish catch (AGFISHCATCH), aquaculture production (AQUACUL), the size of the livestock herd (LVHERD), and the breakdown of land areas (LD). The latter occurs because we do not want these processes to change crop yields (YL).
	~~</div>~~
	\|}		\|}

Wikiadmin at 22:31, 5 September 2018

2018-09-05T22:31:51Z

← Older revision		Revision as of 22:31, 5 September 2018
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	<span style="font-family:arial,helvetica,sans-serif;">Please cite as: Dale S. Rothman, Hughes, Barry B., and Kanishka Narayan. 2017. ''"IFs Agriculture Model Documentation." ''Working paper 2017.07.04. Pardee Center for International Futures, Josef Korbel School of International Studies, University of Denver, Denver, CO. <[https://pardee.du.edu/wiki/Agriculture https://pardee.du.edu/wiki/Agriculture]></span>		<span style="font-family:arial,helvetica,sans-serif;">Please cite as: Dale S. Rothman, Hughes, Barry B., and Kanishka Narayan. 2017. ''"IFs Agriculture Model Documentation." ''Working paper 2017.07.04. Pardee Center for International Futures, Josef Korbel School of International Studies, University of Denver, Denver, CO. Accessed DD Month YYYY <[https://pardee.du.edu/wiki/Agriculture https://pardee.du.edu/wiki/Agriculture]></span>

	The IFs agricultural model tracks the supply and demand, including imports, exports, and prices, of three agricultural commodities: crops, meat, and fish. Crops, meat and fish have direct food, animal feed, industrial and food manufactu<span style="font-family:arial,helvetica,sans-serif;">ring</span> uses. The agricultural model is also where land use dynamics and water use are tracked in IFs, as these are key resources for the agricultural sector.		The IFs agricultural model tracks the supply and demand, including imports, exports, and prices, of three agricultural commodities: crops, meat, and fish. Crops, meat and fish have direct food, animal feed, industrial and food manufactu<span style="font-family:arial,helvetica,sans-serif;">ring</span> uses. The agricultural model is also where land use dynamics and water use are tracked in IFs, as these are key resources for the agricultural sector.
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	</ol></ol>		</ol></ol>
	</ol>		</ol>
	</ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol>		</ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol> </ol>

	*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.		*If AGDOMSUPP > AGP + AGM – AGX, i.e., stocks were being drawn down, increase AGP and AGM while reducing AGX.