Simulace.info - User contributions [en]

WS 2019/2020

2020-01-26T17:10:11Z

Simm04: /* Simulation */

Semestral papers from winter term 2019/2020. Please, put here links to the pages with your paper. First you need to have your [[Assignments WS 2019/2020|assignment approved]]

== Simulation ==
[http://www.simulace.info/index.php/Crop_Rotation_in_sustainable_farming Crop Rotation in sustainable farming], [[User:Simm04|Simm04]] [[User:Simm04|Simm04]] ([[User talk:Simm04|talk]]) 18:10, 26 January 2020 (CET)

[http://www.simulace.info/index.php/Cotton_Processing_Quality:_Cotton,_Seed,_Lint,_Trash Cotton Processing Quality: Cotton, Seed, Lint, Trash] , Ibrahim Aghazada,[[User:Ibrahim Aghazada|Ibrahim Aghazada]] ([[User talk:Ibrahim Aghazada|talk]]) 22:45, 24 January 2020 (CET)

[http://www.simulace.info/index.php/Time_Series_Model_Building_Process Time Series Model Building Process] , [[User:Hazn00|Hazn0000]] ([[User talk:Hazn00|talk]]) 16:15, 20 January 2020 (CET) (done)

[http://www.simulace.info/index.php/Indian_Elephant_Population_in_Thailand Indian Elephant Population in Thailand] , [[User:Xkavj12|Xkavj12]] ([[User talk:Xkavj12|talk]]) 18:42, 20 January 2020 (CET)

[http://www.simulace.info/index.php/Atlantic_Bluefin_Tuna_Population Atlantic Bluefin Tuna Population], [[User:Vokp00|Vokp00]] ([[User talk:Vokp00|talk]]) 20:32, 20 January 2020 (CET)

[http://www.simulace.info/index.php/Shopping_Centre_Simulation Shopping Centre Management Simulation], [[User:Tkad01|Tkad01]] ([[User talk:Tkad01|talk]]) 21:57, 20 January 2020 (CET)

== Textbook Chapters ==
[http://www.simulace.info/index.php/Limits_to_Growth Limits to Growth] , Ibrahim Aghazada, [[User:Ibrahim Aghazada|Ibrahim Aghazada]] ([[User talk:Ibrahim Aghazada|talk]]) 22:44, 24 January 2020 (CET)

Crop Rotation in sustainable farming

2020-01-26T17:06:48Z

Simm04:

=Problem definition=
Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc.

In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs (these were slightly changed from concept) - crop yields, greenhouse gas emissions (N2O, CO2, NH4), soil fertility (nitrogen levels).

I will focus on four crop rotation strategies with three different crops - corn, soybean, wheat:

'''CCC''' (continuous corn) - only corn will be farmed for the whole observed time period (40 years)

'''CS''' (corn-soybean) - rotation of corn and soybean will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, repeat..

'''SSS''' (continuous soybean) - only soybean will be farmed for the whole observed time period (40 years)

'''CSW''' (corn-soybean-wheat) - rotation of corn, soybean and wheat will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, third year wheat, repeat..

Goal of this simulation is to observe dynamic changes with yields, greenhouse gas emissions, tillage strategy and soil nitrogen levels, while changing different crop rotation strategies.

=Method=

Vensim modelling approach was selected due to dynamic behavior of the simulated system.

=Model=

Following vensim model was developed based on the study.
[[File:Crop_rotation_vensim_finished.png|900px|thumb|center|Crop rotation Stock Flow Diagram]]

== Variables ==

===Number of rotated crops===
''Input constant variable which can be changed based on crop strategy. Range <1,3>.''

=1 (in case of CCC and SSS strategies)

=2 (in case of CS strategy)

=3 (in case of CSW strategy)

===Corn production===
''PULSE TRAIN function ensures specific crop to be delivered by time pattern. In crop rotation strategies, if corn is present, it is always first crop, therefore it starts at time 0 (first year), duration is 1 year, repetition is based on number of crops (eg. 2 - it repeats in third year) and final time is set to fixed 40 years according to simulation setup.''

=Corn quantity*PULSE TRAIN(0, 1 , Number of rotated crops ,40)

===Soybean production===
''Similar case as in Corn production variable only with difference of initial year, if sobyean is present in crop rotation strategy, it is always second crop, therefore it starts at time 1 (second year). In case of SSS strategy it starts at time 0 (first year)''

=Soybean quantity*PULSE TRAIN(IF THEN ELSE(Number of rotated crops=1, 0 , 1 ), 1 , Number of rotated crops , 40 )

===Wheat production===
''Similar case as in Corn production variable only with difference of initial year, if wheat is present in crop rotation strategy, it is always third crop, therefore it starts at time 2 (third year).''

=Wheat quantity*PULSE TRAIN(2, 1 , Number of rotated crops , 40 )

===Corn quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,100>.''

=100 (in case of CCC, CS and CSW strategies)

=0 (in case of SSS strategy)

===Soybean quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,40>.''

=40 (in case of CS, SSS and CSW strategies)

=0 (in case of CCC strategy)

===Wheat quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,80>.''

=80 (in case of CSW strategy)

=0 (in case of CCC, CS, SSS strategies)

===increase of N2O emissions===
''Auxiliary variable which changes based on each crop production and its emission coefficient (pattern was extracted from a study),additionaly it changes slightly according to tillage strategy and usage of extra inorganic fertilizer.''

Corn production*Corn N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Soybean production*Soybean N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Wheat production*Wheat N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Inorganic fertilizer/5

===increase of CO2 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Soybean production*Soybean CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Wheat production
*Wheat CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)

===increase of CH4 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Soybean production*Soybean CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Wheat production
*Wheat CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)

===Cumulative N2O emissions===

=INTEG(increase of N2O emissions)

===Cumulative CO2 emissions===

=INTEG(increase of CO2 emissions)

===Cumulative CH4 emissions===

=INTEG(increase of CH4 emissions)

===Corn N2O emission coef===
''Constant variable extracted from study and its data, representing how much N20 emissions is produced while producing corn. Can be adjusted in the future. Further coefficients are similar just crop and emission type changes.''

=0.5

===Soybean N2O emission coef===

=0.07

===Wheat N2O emission coef===

=0.005

===Corn CO2 emission coef===

=0.3

===Soybean CO2 emission coef===

=0.2

===Wheat CO2 emission coef===

=0.25

===Corn CH4 emission coef===

=0.005

===Soybean CH4 emission coef===

=0.01

===Wheat CH4 emission coef===

=0.05

===Inorganic fertilizer===
''Auxiliary variable observes if soil nitrogens decrease below 20 and applies 30 units of fertilizer (which affects NO2 emissions)''

=IF THEN ELSE(Soil nitrogen<20, 30 , 0 )

===Soil nitrogen===
''Level variable observes how much nitrogen in soil increase or decrease''

=INTEG(increase of soil N-decrease of soil N)

===increase of soil N===
''Increase of nitrogen level in soil in this model is triggered either by application of inorganic fertilizer or soybean production (soybean and other legumes increase nitrogen level in soil by its decomposition - extracted from study and its data)''

=Inorganic fertilizer+Soybean production/12

===decrease of soil N===
''Decrease of nitrogen level in soil in this model is triggered either by corn or wheat production (corn and wheat decreasing nitrogen level in soil by its farming - extracted from study and its data)''

=Corn production/8+Wheat production/12

===Soil nitrogen level===
''Auxiliary variable which is dependent on soil nitrogen quantity. According to soil nitrogen levels, it affects yields based on random function with normal distribution. The less soil nitrogen level, the higher negative impact on yields.''

IF THEN ELSE(Soil nitrogen<10, RANDOM NORMAL( 0.3 , 0.5 , 0.45 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=10) :OR: (Soil nitrogen>20)), RANDOM NORMAL( 0.4 , 0.6 , 0.55 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=20) :AND: (Soil nitrogen<30)), RANDOM NORMAL( 0.5 , 0.8 , 0.75 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=30) :AND: (Soil nitrogen<40)), RANDOM NORMAL( 0.7 , 0.9 , 0.85 , 0.05 , 100) , 1 )*
IF THEN ELSE(Soil nitrogen>=40, RANDOM NORMAL( 1 , 1.4 , 1.2 , 0.05 , 100) , 1 )

===Temperature===
''Auxiliary variable which is based on random function with normal distribution. Study showed that extremes in temperatures can have impacts on harvests and yields. Due to complex behavior, I decided to implement only random function.''

=RANDOM NORMAL( 0.9 , 1.1 , 1 , 0.05 , 100)

===Precipitation===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.8 , 1.2 , 1 , 0.05 , 100)

===Pests===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.9 , 1 , 0.98 , 0.005 , 100)

===Natural disasters===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.01 , 1 , 0.99 , 0.05 , 100)

===Tillage===
''Constant variable, which affects yield and emissions. 1 = tilled, 0 = no-till. No-till suppose to be better ecological decision according to study.''

=1 (can be changed to 0)

===increase of C yield===
''Corn yield calculated based on previous variables.''

=Corn production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.05)*Temperature*Precipitation*Pests*Natural disasters

===increase of S yield===
''Soybean yield calculated based on previous variables.''

=Soybean production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.03)*Temperature*Precipitation*Pests*Natural disasters

===increase of W yield===
''Wheat yield calculated based on previous variables.''

=Wheat production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.07)*Temperature*Precipitation*Pests*Natural disasters

===Corn yield===

=INTEG(increase of C yield)

===Soybean yield===

=INTEG(increase of S yield)

===Wheat yield===

=INTEG(increase of W yield)

===Total yield===
''Sum of yields''

=Corn yield + Soybean yield + Wheat yield

=Results=
As explained in problem definition sections, four crop rotation strategy were observed: CCC, CS, SSS, CSW. For each strategy I changed necessary variables and did simulation run. I divided results into yields, N2O and CO2 emissions, CH4 emissions and soil nitrogen for comparsion between mentioned crop rotation strategies.

===Yields===
CCC Yield
[[File:CCC yield.png|400px|CCC Yield]]

CS Yield
[[File:CS yield.png|400px|CS Yield]]

SSS Yield
[[File:SSS yield.png|400px|SSS Yield]]

CSW Yield
[[File:CSW yield.png|400px|CSW Yield]]

===N2O and CO2 emissions===
CCC N2O CO2
[[File:CCC N2O CO2.png|400px|CCC N2O CO2]]

CS N2O CO2
[[File:CS N2O CO2.png|400px|CS N2O CO2]]

SSS N2O CO2
[[File:SSS N2O CO2.png|400px|SSS N2O CO2]]

CSW N2O CO2
[[File:CSW N2O CO2.png|400px|CSW N2O CO2]]

===CH4 emissions===
CCC CH4
[[File:CCC CH4.png|400px|CCC CH4]]

CS CH4
[[File:CS CH4.png|400px|CS CH4]]

SSS CH4
[[File:SSS CH4.png|400px|SSS CH4]]

CSW CH4
[[File:CSW CH4.png|400px|CSW CH4]]

===Soil nitrogen===
CCC soil nitrogen
[[File:CCC soil nitrogen.png|400px|CCC soil nitrogen]]

CS soil nitrogen
[[File:CS soil nitrogen.png|400px|CS soil nitrogen]]

SSS soil nitrogen
[[File:SSS soil nitrogen.png|400px|SSS soil nitrogen]]

CSW soil nitrogen
[[File:CSW soil nitrogen.png|400px|CSW soil nitrogen]]

=Conclusion=

Simulation of such complex evnironment as crop rotation in farming was challenging. Created VENSIM model of crop rotation is simplified with some parameters based on just few studies. Real world behaviour can be different because there are many variables affecting the whole process. Although with dramatic simplification, it can be used as a starting point for creating more complex models in agriculture sector. My goal to demonstrate changing of yield, greenhouse gas emissions and nitrogen level was achieved.

Yields results could be extended with price and demand of market implementation for comparsion with different crop yields.

N2O and CO2 emissions were highest in CCC crop strategy, providing speculation that monoculture is enviromentaly unfriendly in compare with polyculture strategies. SSS strategy was providing lowest N2O emissions, on other hand it showed highest CH4 emissions which are specific for legumes as soybean.

Soil nitrogen levels were highly dependent on soybean in crop rotation strategy. With no soybean in crop strategy - in CCC strategy, dramaticaly more inorganic fertilization inputs were necessary

Due to the scope of model, different tillage scenario (0 - no-til) was not simulated. Provided study concluded higher yield and lower emission levels with tillage sceario (1 - tillage, default for simulated model)

===Model extension===
More complexity can be implemented in the future, for example:

Detailed description of parameteres like Temperature, Pests, Natural disasters or Precipitation.

More crop strategies or new crops.

Market variables like demand or prices of crop seeds or harvesting costs could be also implemented.

Monthly changes (instead of yearly) with more detailed fluctuations during seasons (in Spring there is bigger demand for fertilizers, temperature spikes)

=Code=

[http://www.simulace.info/index.php/File:Crop_rotation_finished.mdl Crop rotation VENSIM model]

=References=

#BEHNKE, Gevan D., Stacy M. ZUBER, Cameron M. PITTELKOW, Emerson D. NAFZIGER a María B. VILLAMIL. Long-term crop rotation and tillage effects on soil greenhouse gas emissions and crop production in Illinois, USA. Agriculture, Ecosystems & Environment [online]. 2018, 261, 62-70 [cit. 2020-01-26]. DOI: 10.1016/j.agee.2018.03.007. ISSN 01678809. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S0167880918301221
#KOLLAS, Chris, Kurt Christian KERSEBAUM, Claas NENDEL, et al. Crop rotation modelling—A European model intercomparison. European Journal of Agronomy [online]. 2015, 70, 98-111 [cit. 2020-01-26]. DOI: 10.1016/j.eja.2015.06.007. ISSN 11610301. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S1161030115300010
#BRANKATSCHK, Gerhard a Matthias FINKBEINER. Modeling crop rotation in agricultural LCAs — Challenges and potential solutions. Agricultural Systems [online]. 2015, 138, 66-76 [cit. 2020-01-26]. DOI: 10.1016/j.agsy.2015.05.008. ISSN 0308521X. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S0308521X1500075X

Crop Rotation in sustainable farming

2020-01-26T17:04:22Z

Simm04:

=Problem definition=
Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc.

In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs (these were slightly changed from concept) - crop yields, greenhouse gas emissions (N2O, CO2, NH4), soil fertility (nitrogen levels).

I will focus on four crop rotation strategies with three different crops - corn, soybean, wheat:

'''CCC''' (continuous corn) - only corn will be farmed for the whole observed time period (40 years)

'''CS''' (corn-soybean) - rotation of corn and soybean will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, repeat..

'''SSS''' (continuous soybean) - only soybean will be farmed for the whole observed time period (40 years)

'''CSW''' (corn-soybean-wheat) - rotation of corn, soybean and wheat will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, third year wheat, repeat..

Goal of this simulation is to observe dynamic changes with yields, greenhouse gas emissions, tillage strategy and soil nitrogen levels, while changing different crop rotation strategies.

=Method=

Vensim modelling approach was selected due to dynamic behavior of the simulated system.

=Model=

Following vensim model was developed based on the study.
[[File:Crop_rotation_vensim_finished.png|900px|thumb|center|Crop rotation Stock Flow Diagram]]

== Variables ==

===Number of rotated crops===
''Input constant variable which can be changed based on crop strategy. Range <1,3>.''

=1 (in case of CCC and SSS strategies)

=2 (in case of CS strategy)

=3 (in case of CSW strategy)

===Corn production===
''PULSE TRAIN function ensures specific crop to be delivered by time pattern. In crop rotation strategies, if corn is present, it is always first crop, therefore it starts at time 0 (first year), duration is 1 year, repetition is based on number of crops (eg. 2 - it repeats in third year) and final time is set to fixed 40 years according to simulation setup.''

=Corn quantity*PULSE TRAIN(0, 1 , Number of rotated crops ,40)

===Soybean production===
''Similar case as in Corn production variable only with difference of initial year, if sobyean is present in crop rotation strategy, it is always second crop, therefore it starts at time 1 (second year). In case of SSS strategy it starts at time 0 (first year)''

=Soybean quantity*PULSE TRAIN(IF THEN ELSE(Number of rotated crops=1, 0 , 1 ), 1 , Number of rotated crops , 40 )

===Wheat production===
''Similar case as in Corn production variable only with difference of initial year, if wheat is present in crop rotation strategy, it is always third crop, therefore it starts at time 2 (third year).''

=Wheat quantity*PULSE TRAIN(2, 1 , Number of rotated crops , 40 )

===Corn quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,100>.''

=100 (in case of CCC, CS and CSW strategies)

=0 (in case of SSS strategy)

===Soybean quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,40>.''

=40 (in case of CS, SSS and CSW strategies)

=0 (in case of CCC strategy)

===Wheat quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,80>.''

=80 (in case of CSW strategy)

=0 (in case of CCC, CS, SSS strategies)

===increase of N2O emissions===
''Auxiliary variable which changes based on each crop production and its emission coefficient (pattern was extracted from a study),additionaly it changes slightly according to tillage strategy and usage of extra inorganic fertilizer.''

Corn production*Corn N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Soybean production*Soybean N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Wheat production*Wheat N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Inorganic fertilizer/5

===increase of CO2 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Soybean production*Soybean CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Wheat production
*Wheat CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)

===increase of CH4 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Soybean production*Soybean CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Wheat production
*Wheat CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)

===Cumulative N2O emissions===

=INTEG(increase of N2O emissions)

===Cumulative CO2 emissions===

=INTEG(increase of CO2 emissions)

===Cumulative CH4 emissions===

=INTEG(increase of CH4 emissions)

===Corn N2O emission coef===
''Constant variable extracted from study and its data, representing how much N20 emissions is produced while producing corn. Can be adjusted in the future. Further coefficients are similar just crop and emission type changes.''

=0.5

===Soybean N2O emission coef===

=0.07

===Wheat N2O emission coef===

=0.005

===Corn CO2 emission coef===

=0.3

===Soybean CO2 emission coef===

=0.2

===Wheat CO2 emission coef===

=0.25

===Corn CH4 emission coef===

=0.005

===Soybean CH4 emission coef===

=0.01

===Wheat CH4 emission coef===

=0.05

===Inorganic fertilizer===
''Auxiliary variable observes if soil nitrogens decrease below 20 and applies 30 units of fertilizer (which affects NO2 emissions)''

=IF THEN ELSE(Soil nitrogen<20, 30 , 0 )

===Soil nitrogen===
''Level variable observes how much nitrogen in soil increase or decrease''

=INTEG(increase of soil N-decrease of soil N)

===increase of soil N===
''Increase of nitrogen level in soil in this model is triggered either by application of inorganic fertilizer or soybean production (soybean and other legumes increase nitrogen level in soil by its decomposition - extracted from study and its data)''

=Inorganic fertilizer+Soybean production/12

===decrease of soil N===
''Decrease of nitrogen level in soil in this model is triggered either by corn or wheat production (corn and wheat decreasing nitrogen level in soil by its farming - extracted from study and its data)''

=Corn production/8+Wheat production/12

===Soil nitrogen level===
''Auxiliary variable which is dependent on soil nitrogen quantity. According to soil nitrogen levels, it affects yields based on random function with normal distribution. The less soil nitrogen level, the higher negative impact on yields.''

IF THEN ELSE(Soil nitrogen<10, RANDOM NORMAL( 0.3 , 0.5 , 0.45 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=10) :OR: (Soil nitrogen>20)), RANDOM NORMAL( 0.4 , 0.6 , 0.55 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=20) :AND: (Soil nitrogen<30)), RANDOM NORMAL( 0.5 , 0.8 , 0.75 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=30) :AND: (Soil nitrogen<40)), RANDOM NORMAL( 0.7 , 0.9 , 0.85 , 0.05 , 100) , 1 )*
IF THEN ELSE(Soil nitrogen>=40, RANDOM NORMAL( 1 , 1.4 , 1.2 , 0.05 , 100) , 1 )

===Temperature===
''Auxiliary variable which is based on random function with normal distribution. Study showed that extremes in temperatures can have impacts on harvests and yields. Due to complex behavior, I decided to implement only random function.''

=RANDOM NORMAL( 0.9 , 1.1 , 1 , 0.05 , 100)

===Precipitation===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.8 , 1.2 , 1 , 0.05 , 100)

===Pests===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.9 , 1 , 0.98 , 0.005 , 100)

===Natural disasters===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.01 , 1 , 0.99 , 0.05 , 100)

===Tillage===
''Constant variable, which affects yield and emissions. 1 = tilled, 0 = no-till. No-till suppose to be better ecological decision according to study.''

=1 (can be changed to 0)

===increase of C yield===
''Corn yield calculated based on previous variables.''

=Corn production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.05)*Temperature*Precipitation*Pests*Natural disasters

===increase of S yield===
''Soybean yield calculated based on previous variables.''

=Soybean production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.03)*Temperature*Precipitation*Pests*Natural disasters

===increase of W yield===
''Wheat yield calculated based on previous variables.''

=Wheat production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.07)*Temperature*Precipitation*Pests*Natural disasters

===Corn yield===

=INTEG(increase of C yield)

===Soybean yield===

=INTEG(increase of S yield)

===Wheat yield===

=INTEG(increase of W yield)

===Total yield===
''Sum of yields''

=Corn yield + Soybean yield + Wheat yield

=Results=
As explained in problem definition sections, four crop rotation strategy were observed: CCC, CS, SSS, CSW. For each strategy I changed necessary variables and did simulation run. I divided results into yields, N2O and CO2 emissions, CH4 emissions and soil nitrogen for comparsion between mentioned crop rotation strategies.

===Yields===
CCC Yield
[[File:CCC yield.png|400px|CCC Yield]]

CS Yield
[[File:CS yield.png|400px|CS Yield]]

SSS Yield
[[File:SSS yield.png|400px|SSS Yield]]

CSW Yield
[[File:CSW yield.png|400px|CSW Yield]]

===N2O and CO2 emissions===
CCC N2O CO2
[[File:CCC N2O CO2.png|400px|CCC N2O CO2]]

CS N2O CO2
[[File:CS N2O CO2.png|400px|CS N2O CO2]]

SSS N2O CO2
[[File:SSS N2O CO2.png|400px|SSS N2O CO2]]

CSW N2O CO2
[[File:CSW N2O CO2.png|400px|CSW N2O CO2]]

===CH4 emissions===
CCC CH4
[[File:CCC CH4.png|400px|CCC CH4]]

CS CH4
[[File:CS CH4.png|400px|CS CH4]]

SSS CH4
[[File:SSS CH4.png|400px|SSS CH4]]

CSW CH4
[[File:CSW CH4.png|400px|CSW CH4]]

===Soil nitrogen===
CCC soil nitrogen
[[File:CCC soil nitrogen.png|400px|CCC soil nitrogen]]

CS soil nitrogen
[[File:CS soil nitrogen.png|400px|CS soil nitrogen]]

SSS soil nitrogen
[[File:SSS soil nitrogen.png|400px|SSS soil nitrogen]]

CSW soil nitrogen
[[File:CSW soil nitrogen.png|400px|CSW soil nitrogen]]

=Conclusion=

Simulation of such complex evnironment as crop rotation in farming was challenging. Created VENSIM model of crop rotation is simplified with some parameters based on just few studies. Real world behaviour can be different because there are many variables affecting the whole process. Although with dramatic simplification, it can be used as a starting point for creating more complex models in agriculture sector. My goal to demonstrate changing of yield, greenhouse gas emissions and nitrogen level was achieved.

Yields results could be extended with price and demand of market implementation for comparsion with different crop yields.

N2O and CO2 emissions were highest in CCC crop strategy, providing speculation that monoculture is enviromentaly unfriendly in compare with polyculture strategies. SSS strategy was providing lowest N2O emissions, on other hand it showed highest CH4 emissions which are specific for legumes as soybean.

Soil nitrogen levels were highly dependent on soybean in crop rotation strategy. With no soybean in crop strategy - in CCC strategy, dramaticaly more inorganic fertilization inputs were necessary

Due to the scope of model, different tillage scenario (0 - no-til) was not simulated. Provided study concluded higher yield and lower emission levels with tillage sceario (1 - tillage, default for simulated model)

===Model extension===
More complexity can be implemented in the future, for example:

Detailed description of parameteres like Temperature, Pests, Natural disasters or Precipitation.
More crop strategies or new crops.
Market variables like demand or prices of crop seeds or harvesting costs could be also implemented.
Monthly changes (instead of yearly) with more detailed fluctuations during seasons (in Spring there is bigger demand for fertilizers, temperature spikes)

=Code=

[http://www.simulace.info/index.php/File:Crop_rotation_finished.mdl Crop rotation VENSIM model]

=References=

#BEHNKE, Gevan D., Stacy M. ZUBER, Cameron M. PITTELKOW, Emerson D. NAFZIGER a María B. VILLAMIL. Long-term crop rotation and tillage effects on soil greenhouse gas emissions and crop production in Illinois, USA. Agriculture, Ecosystems & Environment [online]. 2018, 261, 62-70 [cit. 2020-01-26]. DOI: 10.1016/j.agee.2018.03.007. ISSN 01678809. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S0167880918301221
#KOLLAS, Chris, Kurt Christian KERSEBAUM, Claas NENDEL, et al. Crop rotation modelling—A European model intercomparison. European Journal of Agronomy [online]. 2015, 70, 98-111 [cit. 2020-01-26]. DOI: 10.1016/j.eja.2015.06.007. ISSN 11610301. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S1161030115300010
#BRANKATSCHK, Gerhard a Matthias FINKBEINER. Modeling crop rotation in agricultural LCAs — Challenges and potential solutions. Agricultural Systems [online]. 2015, 138, 66-76 [cit. 2020-01-26]. DOI: 10.1016/j.agsy.2015.05.008. ISSN 0308521X. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S0308521X1500075X

Crop Rotation in sustainable farming

2020-01-26T16:39:25Z

Simm04:

=Problem definition=
Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc.

In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs (these were slightly changed from concept) - crop yields, greenhouse gas emissions (N2O, CO2, NH4), soil fertility (nitrogen levels).

I will focus on four crop rotation strategies with three different crops - corn, soybean, wheat:

'''CCC''' (continuous corn) - only corn will be farmed for the whole observed time period (40 years)

'''CS''' (corn-soybean) - rotation of corn and soybean will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, repeat..

'''SSS''' (continuous soybean) - only soybean will be farmed for the whole observed time period (40 years)

'''CSW''' (corn-soybean-wheat) - rotation of corn, soybean and wheat will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, third year wheat, repeat..

Goal of this simulation is to observe dynamic changes with yields, greenhouse gas emissions, tillage strategy and soil nitrogen levels, while changing different crop rotation strategies.

=Method=

Vensim modelling approach was selected due to dynamic behavior of the simulated system.

=Model=

Following vensim model was developed based on the study.
[[File:Crop_rotation_vensim_finished.png|900px|thumb|center|Crop rotation Stock Flow Diagram]]

== Variables ==

===Number of rotated crops===
''Input constant variable which can be changed based on crop strategy. Range <1,3>.''

=1 (in case of CCC and SSS strategies)

=2 (in case of CS strategy)

=3 (in case of CSW strategy)

===Corn production===
''PULSE TRAIN function ensures specific crop to be delivered by time pattern. In crop rotation strategies, if corn is present, it is always first crop, therefore it starts at time 0 (first year), duration is 1 year, repetition is based on number of crops (eg. 2 - it repeats in third year) and final time is set to fixed 40 years according to simulation setup.''

=Corn quantity*PULSE TRAIN(0, 1 , Number of rotated crops ,40)

===Soybean production===
''Similar case as in Corn production variable only with difference of initial year, if sobyean is present in crop rotation strategy, it is always second crop, therefore it starts at time 1 (second year). In case of SSS strategy it starts at time 0 (first year)''

=Soybean quantity*PULSE TRAIN(IF THEN ELSE(Number of rotated crops=1, 0 , 1 ), 1 , Number of rotated crops , 40 )

===Wheat production===
''Similar case as in Corn production variable only with difference of initial year, if wheat is present in crop rotation strategy, it is always third crop, therefore it starts at time 2 (third year).''

=Wheat quantity*PULSE TRAIN(2, 1 , Number of rotated crops , 40 )

===Corn quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,100>.''

=100 (in case of CCC, CS and CSW strategies)

=0 (in case of SSS strategy)

===Soybean quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,40>.''

=40 (in case of CS, SSS and CSW strategies)

=0 (in case of CCC strategy)

===Wheat quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,80>.''

=80 (in case of CSW strategy)

=0 (in case of CCC, CS, SSS strategies)

===increase of N2O emissions===
''Auxiliary variable which changes based on each crop production and its emission coefficient (pattern was extracted from a study),additionaly it changes slightly according to tillage strategy and usage of extra inorganic fertilizer.''

Corn production*Corn N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Soybean production*Soybean N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Wheat production*Wheat N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Inorganic fertilizer/5

===increase of CO2 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Soybean production*Soybean CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Wheat production
*Wheat CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)

===increase of CH4 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Soybean production*Soybean CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Wheat production
*Wheat CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)

===Cumulative N2O emissions===

=INTEG(increase of N2O emissions)

===Cumulative CO2 emissions===

=INTEG(increase of CO2 emissions)

===Cumulative CH4 emissions===

=INTEG(increase of CH4 emissions)

===Corn N2O emission coef===
''Constant variable extracted from study and its data, representing how much N20 emissions is produced while producing corn. Can be adjusted in the future. Further coefficients are similar just crop and emission type changes.''

=0.5

===Soybean N2O emission coef===

=0.07

===Wheat N2O emission coef===

=0.005

===Corn CO2 emission coef===

=0.3

===Soybean CO2 emission coef===

=0.2

===Wheat CO2 emission coef===

=0.25

===Corn CH4 emission coef===

=0.005

===Soybean CH4 emission coef===

=0.01

===Wheat CH4 emission coef===

=0.05

===Inorganic fertilizer===
''Auxiliary variable observes if soil nitrogens decrease below 20 and applies 30 units of fertilizer (which affects NO2 emissions)''

=IF THEN ELSE(Soil nitrogen<20, 30 , 0 )

===Soil nitrogen===
''Level variable observes how much nitrogen in soil increase or decrease''

=INTEG(increase of soil N-decrease of soil N)

===increase of soil N===
''Increase of nitrogen level in soil in this model is triggered either by application of inorganic fertilizer or soybean production (soybean and other legumes increase nitrogen level in soil by its decomposition - extracted from study and its data)''

=Inorganic fertilizer+Soybean production/12

===decrease of soil N===
''Decrease of nitrogen level in soil in this model is triggered either by corn or wheat production (corn and wheat decreasing nitrogen level in soil by its farming - extracted from study and its data)''

=Corn production/8+Wheat production/12

===Soil nitrogen level===
''Auxiliary variable which is dependent on soil nitrogen quantity. According to soil nitrogen levels, it affects yields based on random function with normal distribution. The less soil nitrogen level, the higher negative impact on yields.''

IF THEN ELSE(Soil nitrogen<10, RANDOM NORMAL( 0.3 , 0.5 , 0.45 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=10) :OR: (Soil nitrogen>20)), RANDOM NORMAL( 0.4 , 0.6 , 0.55 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=20) :AND: (Soil nitrogen<30)), RANDOM NORMAL( 0.5 , 0.8 , 0.75 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=30) :AND: (Soil nitrogen<40)), RANDOM NORMAL( 0.7 , 0.9 , 0.85 , 0.05 , 100) , 1 )*
IF THEN ELSE(Soil nitrogen>=40, RANDOM NORMAL( 1 , 1.4 , 1.2 , 0.05 , 100) , 1 )

===Temperature===
''Auxiliary variable which is based on random function with normal distribution. Study showed that extremes in temperatures can have impacts on harvests and yields. Due to complex behavior, I decided to implement only random function.''

=RANDOM NORMAL( 0.9 , 1.1 , 1 , 0.05 , 100)

===Precipitation===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.8 , 1.2 , 1 , 0.05 , 100)

===Pests===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.9 , 1 , 0.98 , 0.005 , 100)

===Natural disasters===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.01 , 1 , 0.99 , 0.05 , 100)

===Tillage===
''Constant variable, which affects yield and emissions. 1 = tilled, 0 = no-till. No-till suppose to be better ecological decision according to study.''

=1 (can be changed to 0)

===increase of C yield===
''Corn yield calculated based on previous variables.''

=Corn production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.05)*Temperature*Precipitation*Pests*Natural disasters

===increase of S yield===
''Soybean yield calculated based on previous variables.''

=Soybean production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.03)*Temperature*Precipitation*Pests*Natural disasters

===increase of W yield===
''Wheat yield calculated based on previous variables.''

=Wheat production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.07)*Temperature*Precipitation*Pests*Natural disasters

===Corn yield===

=INTEG(increase of C yield)

===Soybean yield===

=INTEG(increase of S yield)

===Wheat yield===

=INTEG(increase of W yield)

===Total yield===
''Sum of yields''

=Corn yield + Soybean yield + Wheat yield

=Results=
As explained in problem definition sections, four crop rotation strategy were observed: CCC, CS, SSS, CSW. For each strategy I changed necessary variables and did simulation run. I divided results into yields, N2O and CO2 emissions, CH4 emissions and soil nitrogen for comparsion between mentioned crop rotation strategies.

===Yields===
CCC Yield
[[File:CCC yield.png|400px|CCC Yield]]

CS Yield
[[File:CS yield.png|400px|CS Yield]]

SSS Yield
[[File:SSS yield.png|400px|SSS Yield]]

CSW Yield
[[File:CSW yield.png|400px|CSW Yield]]

===N2O and CO2 emissions===
CCC N2O CO2
[[File:CCC N2O CO2.png|400px|CCC N2O CO2]]

CS N2O CO2
[[File:CS N2O CO2.png|400px|CS N2O CO2]]

SSS N2O CO2
[[File:SSS N2O CO2.png|400px|SSS N2O CO2]]

CSW N2O CO2
[[File:CSW N2O CO2.png|400px|CSW N2O CO2]]

===CH4 emissions===
CCC CH4
[[File:CCC CH4.png|400px|CCC CH4]]

CS CH4
[[File:CS CH4.png|400px|CS CH4]]

SSS CH4
[[File:SSS CH4.png|400px|SSS CH4]]

CSW CH4
[[File:CSW CH4.png|400px|CSW CH4]]

===Soil nitrogen===
CCC soil nitrogen
[[File:CCC soil nitrogen.png|400px|CCC soil nitrogen]]

CS soil nitrogen
[[File:CS soil nitrogen.png|400px|CS soil nitrogen]]

SSS soil nitrogen
[[File:SSS soil nitrogen.png|400px|SSS soil nitrogen]]

CSW soil nitrogen
[[File:CSW soil nitrogen.png|400px|CSW soil nitrogen]]

=Conclusion=

=Code=

[http://www.simulace.info/index.php/File:Crop_rotation_finished.mdl Crop rotation VENSIM model]

=References=

#BEHNKE, Gevan D., Stacy M. ZUBER, Cameron M. PITTELKOW, Emerson D. NAFZIGER a María B. VILLAMIL. Long-term crop rotation and tillage effects on soil greenhouse gas emissions and crop production in Illinois, USA. Agriculture, Ecosystems & Environment [online]. 2018, 261, 62-70 [cit. 2020-01-26]. DOI: 10.1016/j.agee.2018.03.007. ISSN 01678809. Availiable: https://linkinghub.elsevier.com/retrieve/pii/S0167880918301221
#
#

File:Crop rotation finished.mdl

2020-01-26T16:37:11Z

Simm04:

File:SSS yield.png

2020-01-26T16:16:02Z

Simm04:

File:SSS soil nitrogen.png

2020-01-26T16:15:54Z

Simm04:

File:SSS N2O CO2.png

2020-01-26T16:15:46Z

Simm04:

File:SSS CH4.png

2020-01-26T16:15:33Z

Simm04:

File:CSW yield.png

2020-01-26T16:14:46Z

Simm04:

File:CSW soil nitrogen.png

2020-01-26T16:14:31Z

Simm04:

File:CSW N2O CO2.png

2020-01-26T16:14:20Z

Simm04:

File:CSW CH4.png

2020-01-26T16:14:12Z

Simm04:

File:CS yield.png

2020-01-26T16:13:45Z

Simm04:

File:CS soil nitrogen.png

2020-01-26T16:13:28Z

Simm04:

File:CS N2O CO2.png

2020-01-26T16:13:08Z

Simm04:

File:CS CH4.png

2020-01-26T16:12:57Z

Simm04:

File:CCC yield.png

2020-01-26T16:12:44Z

Simm04:

File:CCC soil nitrogen.png

2020-01-26T16:12:33Z

Simm04:

File:CCC N2O CO2.png

2020-01-26T16:12:23Z

Simm04:

File:CCC CH4.png

2020-01-26T16:12:14Z

Simm04:

Crop Rotation in sustainable farming

2020-01-26T16:09:54Z

Simm04:

=Problem definition=
Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc.

In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs (these were slightly changed from concept) - crop yields, greenhouse gas emissions (N2O, CO2, NH4), soil fertility (nitrogen levels).

I will focus on four crop rotation strategies with three different crops - corn, soybean, wheat:

'''CCC''' (continuous corn) - only corn will be farmed for the whole observed time period (40 years)

'''CS''' (corn-soybean) - rotation of corn and soybean will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, repeat..

'''SSS''' (continuous soybean) - only soybean will be farmed for the whole observed time period (40 years)

'''CSW''' (corn-soybean-wheat) - rotation of corn, soybean and wheat will be used in year cycles for the whole observed time period (40 years), first year corn, second year soybean, third year wheat, repeat..

Goal of this simulation is to observe dynamic changes with yields, greenhouse gas emissions, tillage strategy and soil nitrogen levels, while changing different crop rotation strategies.

=Method=

Vensim modelling approach was selected due to dynamic behavior of the simulated system.

=Model=

Following vensim model was developed based on the study.
[[File:Crop_rotation_vensim_finished.png|900px|thumb|center|Crop rotation Stock Flow Diagram]]

== Variables ==

===Number of rotated crops===
''Input constant variable which can be changed based on crop strategy. Range <1,3>.''

=1 (in case of CCC and SSS strategies)

=2 (in case of CS strategy)

=3 (in case of CSW strategy)

===Corn production===
''PULSE TRAIN function ensures specific crop to be delivered by time pattern. In crop rotation strategies, if corn is present, it is always first crop, therefore it starts at time 0 (first year), duration is 1 year, repetition is based on number of crops (eg. 2 - it repeats in third year) and final time is set to fixed 40 years according to simulation setup.''

=Corn quantity*PULSE TRAIN(0, 1 , Number of rotated crops ,40)

===Soybean production===
''Similar case as in Corn production variable only with difference of initial year, if sobyean is present in crop rotation strategy, it is always second crop, therefore it starts at time 1 (second year). In case of SSS strategy it starts at time 0 (first year)''

=Soybean quantity*PULSE TRAIN(IF THEN ELSE(Number of rotated crops=1, 0 , 1 ), 1 , Number of rotated crops , 40 )

===Wheat production===
''Similar case as in Corn production variable only with difference of initial year, if wheat is present in crop rotation strategy, it is always third crop, therefore it starts at time 2 (third year).''

=Wheat quantity*PULSE TRAIN(2, 1 , Number of rotated crops , 40 )

===Corn quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,100>.''

=100 (in case of CCC, CS and CSW strategies)

=0 (in case of SSS strategy)

===Soybean quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,40>.''

=40 (in case of CS, SSS and CSW strategies)

=0 (in case of CCC strategy)

===Wheat quantity===
''Input constant variable which can be changed based on crop strategy. Range <0,80>.''

=80 (in case of CSW strategy)

=0 (in case of CCC, CS, SSS strategies)

===increase of N2O emissions===
''Auxiliary variable which changes based on each crop production and its emission coefficient (pattern was extracted from a study),additionaly it changes slightly according to tillage strategy and usage of extra inorganic fertilizer.''

Corn production*Corn N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Soybean production*Soybean N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Wheat production*Wheat N2O emission coef*IF THEN ELSE(Tillage=0, 1.5 , 1.4)+
Inorganic fertilizer/5

===increase of CO2 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Soybean production*Soybean CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)+Wheat production
*Wheat CO2 emission coef*IF THEN ELSE(Tillage=0, 3 , 2.9)

===increase of CH4 emissions===
''Similar auxiliary variable as increase of N20 emissions extra except zero effect with inorganic fertilizer.''

Corn production*Corn CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Soybean production*Soybean CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)+Wheat production
*Wheat CH4 emission coef*IF THEN ELSE(Tillage=0, 0.3 , 0.2)

===Cumulative N2O emissions===

=INTEG(increase of N2O emissions)

===Cumulative CO2 emissions===

=INTEG(increase of CO2 emissions)

===Cumulative CH4 emissions===

=INTEG(increase of CH4 emissions)

===Corn N2O emission coef===
''Constant variable extracted from study and its data, representing how much N20 emissions is produced while producing corn. Can be adjusted in the future. Further coefficients are similar just crop and emission type changes.''

=0.5

===Soybean N2O emission coef===

=0.07

===Wheat N2O emission coef===

=0.005

===Corn CO2 emission coef===

=0.3

===Soybean CO2 emission coef===

=0.2

===Wheat CO2 emission coef===

=0.25

===Corn CH4 emission coef===

=0.005

===Soybean CH4 emission coef===

=0.01

===Wheat CH4 emission coef===

=0.05

===Inorganic fertilizer===
''Auxiliary variable observes if soil nitrogens decrease below 20 and applies 30 units of fertilizer (which affects NO2 emissions)''

=IF THEN ELSE(Soil nitrogen<20, 30 , 0 )

===Soil nitrogen===
''Level variable observes how much nitrogen in soil increase or decrease''

=INTEG(increase of soil N-decrease of soil N)

===increase of soil N===
''Increase of nitrogen level in soil in this model is triggered either by application of inorganic fertilizer or soybean production (soybean and other legumes increase nitrogen level in soil by its decomposition - extracted from study and its data)''

=Inorganic fertilizer+Soybean production/12

===decrease of soil N===
''Decrease of nitrogen level in soil in this model is triggered either by corn or wheat production (corn and wheat decreasing nitrogen level in soil by its farming - extracted from study and its data)''

=Corn production/8+Wheat production/12

===Soil nitrogen level===
''Auxiliary variable which is dependent on soil nitrogen quantity. According to soil nitrogen levels, it affects yields based on random function with normal distribution. The less soil nitrogen level, the higher negative impact on yields.''

IF THEN ELSE(Soil nitrogen<10, RANDOM NORMAL( 0.3 , 0.5 , 0.45 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=10) :OR: (Soil nitrogen>20)), RANDOM NORMAL( 0.4 , 0.6 , 0.55 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=20) :AND: (Soil nitrogen<30)), RANDOM NORMAL( 0.5 , 0.8 , 0.75 , 0.05 , 100) , 1 )*
IF THEN ELSE(((Soil nitrogen>=30) :AND: (Soil nitrogen<40)), RANDOM NORMAL( 0.7 , 0.9 , 0.85 , 0.05 , 100) , 1 )*
IF THEN ELSE(Soil nitrogen>=40, RANDOM NORMAL( 1 , 1.4 , 1.2 , 0.05 , 100) , 1 )

===Temperature===
''Auxiliary variable which is based on random function with normal distribution. Study showed that extremes in temperatures can have impacts on harvests and yields. Due to complex behavior, I decided to implement only random function.''

=RANDOM NORMAL( 0.9 , 1.1 , 1 , 0.05 , 100)

===Precipitation===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.8 , 1.2 , 1 , 0.05 , 100)

===Pests===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.9 , 1 , 0.98 , 0.005 , 100)

===Natural disasters===
''Auxiliary variable, similar to Temperature variable only with different min and max parameters''

=RANDOM NORMAL( 0.01 , 1 , 0.99 , 0.05 , 100)

===Tillage===
''Constant variable, which affects yield and emissions. 1 = tilled, 0 = no-till. No-till suppose to be better ecological decision according to study.''

=1 (can be changed to 0)

===increase of C yield===
''Corn yield calculated based on previous variables.''

=Corn production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.05)*Temperature*Precipitation*Pests*Natural disasters

===increase of S yield===
''Soybean yield calculated based on previous variables.''

=Soybean production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.03)*Temperature*Precipitation*Pests*Natural disasters

===increase of W yield===
''Wheat yield calculated based on previous variables.''

=Wheat production*Soil nitrogen level*IF THEN ELSE(Tillage=0, 1, 1.07)*Temperature*Precipitation*Pests*Natural disasters

===Corn yield===

=INTEG(increase of C yield)

===Soybean yield===

=INTEG(increase of S yield)

===Wheat yield===

=INTEG(increase of W yield)

===Total yield===
''Sum of yields''

=Corn yield + Soybean yield + Wheat yield

=Results=
As explained in problem definition sections, four crop rotation strategy were observed: CCC, CS, SSS, CSW. For each strategy I changed necessary variables and did simulation run. I divided results into yields, N2O and CO2 emissions, CH4 emissions and soil nitrogen for comparsion between mentioned crop rotation strategies.

===Yields===
[[File:CCC yield.png]]

[[File:CS yield.png]]

[[File:SSS yield.png]]

[[File:CSW yield.png]]

===N2O and CO2 emissions===
[[File:CCC N2O CO2.png]]

[[File:CS N2O CO2.png]]

[[File:SSS N2O CO2.png]]

[[File:CSW N2O CO2.png]]

===CH4 emissions===
[[File:CCC CH4.png]]

[[File:CS CH4.png]]

[[File:SSS CH4.png]]

[[File:CSW CH4.png]]

===Soil nitrogen===
[[File:CCC soil nitrogen.png]]

[[File:CS soil nitrogen.png]]

[[File:SSS soil nitrogen.png]]

[[File:CSW soil nitrogen.png]]

=Conclusion=

=Code=

=References=

File:Crop rotation vensim finished.png

2020-01-26T15:55:24Z

Simm04:

Crop Rotation in sustainable farming

2020-01-26T15:21:36Z

Simm04:

Crop Rotation in sustainable farming

2020-01-26T14:55:14Z

Simm04:

Crop Rotation in sustainable farming

2020-01-26T14:45:41Z

Simm04:

Crop Rotation in sustainable farming

2020-01-26T14:43:56Z

Simm04:

WS 2019/2020

2020-01-23T14:41:40Z

Simm04: /* Simulation */

Semestral papers from winter term 2019/2020. Please, put here links to the pages with your paper. First you need to have your [[Assignments WS 2019/2020|assignment approved]]

== Simulation ==
[http://www.simulace.info/index.php/Crop_Rotation_in_sustainable_farming Crop Rotation in sustainable farming], [[User:Simm04|Simm04]] ([[User talk:Simm04|talk]]) 15:41, 23 January 2020 (CET) (in progress)

[http://www.simulace.info/index.php/Cotton_Processing_Quality:_Cotton,_Seed,_Lint,_Trash Cotton Processing Quality: Cotton, Seed, Lint, Trash] , Ibrahim Aghazada (in progress)

[http://www.simulace.info/index.php/Time_Series_Model_Building_Process Time Series Model Building Process] , [[User:Hazn00|Hazn0000]] ([[User talk:Hazn00|talk]]) 16:15, 20 January 2020 (CET) (done)

[http://www.simulace.info/index.php/Indian_Elephant_Population_in_Thailand Indian Elephant Population in Thailand] , [[User:Xkavj12|Xkavj12]] ([[User talk:Xkavj12|talk]]) 18:42, 20 January 2020 (CET)

[http://www.simulace.info/index.php/Atlantic_Bluefin_Tuna_Population Atlantic Bluefin Tuna Population], [[User:Vokp00|Vokp00]] ([[User talk:Vokp00|talk]]) 20:32, 20 January 2020 (CET)

[http://www.simulace.info/index.php/Shopping_Centre_Simulation Shopping Centre Management Simulation], [[User:Tkad01|Tkad01]] ([[User talk:Tkad01|talk]]) 21:57, 20 January 2020 (CET)

== Textbook Chapters ==
[http://www.simulace.info/index.php/Limits_to_Growth Limits to Growth] , Ibrahim Aghazada

Crop Rotation in sustainable farming

2020-01-23T14:41:07Z

Simm04: Created page with "=Problem definition= =Method= =Model= =Results= =Conclusion= =Code= =References="

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Assignments WS 2019/2020

2019-12-12T19:03:45Z

Simm04:

{{Ambox
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Please, put here your assignments. Do not forget to sign them. You can use <nowiki>~~~~</nowiki> (four tildas) for an automatic signature. Use Show preview in order to check the result before your final sumbition.
</div>
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{{Ambox
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Please, strive to formulate your assignment carefully. We expect an adequate effort to formulate the assignment as it is your semestral paper. Do not forget that your main goal is a research paper. It means your simulation model must generate the results that are specific, measurable and verifiable. Think twice how you will develop your model, which entities you will use, draw a model diagram, consider what you will measure. No sooner than when you have a good idea about the model, submit your assignment. And of course, read [[How to deal with the simulation assignment|How to deal with the simulation assignment]].
</div>
}}

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Topics on gambling, cards, etc. are not welcome.
</div>
}}

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In order to avoid possible confusion, please, check if you have added '''approved''' in bold somewhere in our comment under your submission. If there is no '''approved''', it means the assignment was not approved yet.
</div>
}}

== Simulation Proposal - Orders completion in a warehouse ==

We need to optimize number of warehouse workers and packaging stations in a warehouse with cca 20 000 different products stored. There are workers that work on picking the products for orders from stock positions and there is also one worker per packaging station assigned. Picking products for one regular order takes 15 minutes on average and for one B2B order takes 90 minutes on average. Packaging one regular order takes 2 minutes on average and B2B order takes 45 minutes on average. Ratio of regular to B2B orders is 25:1.
We want to find out optimal set up of number of workers and packaging stations.

'''Title:''' Orders completion in a warehouse

'''Author:''' Ján Káva

'''Model type:''' Discrete event

'''Modeling tool:''' Simprocess

== Simulation Proposal - Santa Clause Elves & Scattered Gifts ==

This simulation is inspired by couple of animation movies from my childhood. Imagine, sleigh of the Santa crashed and all the gifts scattered. Elves try to move around and calculate all the gifts by moving to the sleigh. So, each elf moves randomly until he will found a gift, then he carries the gift to the sleigh. After he will put gift into sleigh he will perform operations again. The process will continue until all the gifts will be in sleigh.

'''Title:'''Santa Clause Elves & Scattered Gifts

'''Author:''' Ibrahim Aghazada

'''Model type:''' Multi Agent

'''Modeling tool:''' NetLogo

== Simulation Proposal - Atlantic Bluefin Tuna Population==

The population of tuna worldwide is decreasing due to being overfished. Yet some studies claim, that overfishing is not the main cause of the tuna population reduction. Christelle Ravier and Jean-Marc Fromentin in their paper "Long-term fluctuations in the eastern Atlantic and Mediterranean bluefin tuna population" came to the conclusion that the bluefin tuna population may be influence by biotic and environmental factors more than by overexploitation. This simulation will use available data of population size, juvenile death, environmental influences, fishing statistics and other to investigate whether overfishing is the main culprit for bluefin tuna population decline.

'''Title:''' Atlantic Bluefin Tuna Population

'''Author:''' Petra Vokálová, [[User:Vokp00|Vokp00]] ([[User talk:Vokp00|talk]]) 07:43, 9 December 2019 (CET)

'''Model type:''' Stock and flow diagram

'''Modeling tool:''' Vensim

:: [[User:Oleg.Svatos|Oleg.Svatos]] ([[User talk:Oleg.Svatos|talk]]) 22:09, 11 December 2019 (CET) '''Approved'''. Make sure that you describe in detail in the report, how you have derived the equations from the available data (proving so that they are based on relevant data).

== Simulation Proposal - Crop Rotation in sustainable farming==

Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc. In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs - high soil fertility, low soil erosion, good quality crops, high crop field and therefore higher revenue.

'''Title:''' Crop Rotation in sustainable farming

'''Author:''' Michal Šimánek, [[User:Simm04|Simm04]] ([[User talk:Simm04|talk]]) 20:33, 10 December 2019 (CET)

'''Model type:''' Stock and flow diagram

'''Modeling tool:''' Vensim

:: [[User:Oleg.Svatos|Oleg.Svatos]] ([[User talk:Oleg.Svatos|talk]]) 22:13, 11 December 2019 (CET) What data will you build (derive the equations) your simulation on?

:: [[User:Simm04|Simm04]] ([[User talk:Simm04|talk]]) 20:02, 12 December 2019 (CET) I would use available dataset from https://www.nature.com/articles/s41598-017-14271-6#Sec16

Assignments WS 2019/2020

2019-12-10T19:35:00Z

Simm04:

{{Ambox
| text = <div>
Please, put here your assignments. Do not forget to sign them. You can use <nowiki>~~~~</nowiki> (four tildas) for an automatic signature. Use Show preview in order to check the result before your final sumbition.
</div>
}}

{{Ambox
| text = <div>
Please, strive to formulate your assignment carefully. We expect an adequate effort to formulate the assignment as it is your semestral paper. Do not forget that your main goal is a research paper. It means your simulation model must generate the results that are specific, measurable and verifiable. Think twice how you will develop your model, which entities you will use, draw a model diagram, consider what you will measure. No sooner than when you have a good idea about the model, submit your assignment. And of course, read [[How to deal with the simulation assignment|How to deal with the simulation assignment]].
</div>
}}

{{Ambox
| text = <div>
Topics on gambling, cards, etc. are not welcome.
</div>
}}

{{Ambox
| type = content
| text = <div>
In order to avoid possible confusion, please, check if you have added '''approved''' in bold somewhere in our comment under your submission. If there is no '''approved''', it means the assignment was not approved yet.
</div>
}}

== Simulation Proposal - Santa Clause Elves & Scattered Gifts ==

This simulation is inspired by couple of animation movies from my childhood. Imagine, sleigh of the Santa crashed and all the gifts scattered. Elves try to move around and calculate all the gifts by moving to the sleigh. So, each elf moves randomly until he will found a gift, then he carries the gift to the sleigh. After he will put gift into sleigh he will perform operations again. The process will continue until all the gifts will be in sleigh.

'''Title:'''Santa Clause Elves & Scattered Gifts

'''Author:''' Ibrahim Aghazada

'''Model type:''' Multi Agent

'''Modeling tool:''' NetLogo

== Simulation Proposal - Atlantic Bluefin Tuna Population==

The population of tuna worldwide is decreasing due to being overfished. Yet some studies claim, that overfishing is not the main cause of the tuna population reduction. Christelle Ravier and Jean-Marc Fromentin in their paper "Long-term fluctuations in the eastern Atlantic and Mediterranean bluefin tuna population" came to the conclusion that the bluefin tuna population may be influence by biotic and environmental factors more than by overexploitation. This simulation will use available data of population size, juvenile death, environmental influences, fishing statistics and other to investigate whether overfishing is the main culprit for bluefin tuna population decline.

'''Title:''' Atlantic Bluefin Tuna Population

'''Author:''' Petra Vokálová, [[User:Vokp00|Vokp00]] ([[User talk:Vokp00|talk]]) 07:43, 9 December 2019 (CET)

'''Model type:''' Stock and flow diagram

'''Modeling tool:''' Vensim

== Simulation Proposal - Crop Rotation in sustainable farming==

Crop rotation is based on growing a series of different types of crops in the same area in sequential seasons. The planned rotation may vary from a growing season to a few years or even longer periods. It is one of the most effective agricultural control strategies that is used in preventing the loss of soil fertility. It also helps in reducing soil erosion and increases crop yield. Planning an effective crop rotation requires weighing fixed and fluctuating production circumstances: market, farm size, labor supply, climate, soil type, growing practices, etc. In this simulation I will try to find parameters which have impact on the whole process of crop rotation with goal to find model providing desired outputs - high soil fertility, low soil erosion, good quality crops, high crop field and therefore higher revenue.

'''Title:''' Crop Rotation in sustainable farming

'''Author:''' Michal Šimánek, [[User:Simm04|Simm04]] ([[User talk:Simm04|talk]]) 20:33, 10 December 2019 (CET)

'''Model type:''' Stock and flow diagram

'''Modeling tool:''' Vensim