Difference between revisions of "Crop Rotation in sustainable farming"
| Line 14: | Line 14: | ||
'''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.. | '''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 and soil nitrogen levels, while changing different crop rotation strategies. | + | 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= | =Method= | ||
| Line 35: | Line 35: | ||
===Corn production=== | ===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) | =Corn quantity*PULSE TRAIN(0, 1 , Number of rotated crops ,40) | ||
===Soybean production=== | ===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=== | ===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=== | ===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=== | ===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=== | ===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=== | ===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=== | ===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=== | ===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=== | ===Cumulative N2O emissions=== | ||
===Cumulative CO2 emissions=== | ===Cumulative CO2 emissions=== | ||
| Line 81: | Line 119: | ||
===Wheat yield=== | ===Wheat yield=== | ||
===Total yield=== | ===Total yield=== | ||
| − | = Corn yield + Soybean yield + Wheat yield | + | =Corn yield + Soybean yield + Wheat yield |
=Results= | =Results= | ||
Revision as of 16:21, 26 January 2020
Contents
- 1 Problem definition
- 2 Method
- 3 Model
- 3.1 Variables
- 3.1.1 Number of rotated crops
- 3.1.2 Corn production
- 3.1.3 Soybean production
- 3.1.4 Wheat production
- 3.1.5 Corn quantity
- 3.1.6 Soybean quantity
- 3.1.7 Wheat quantity
- 3.1.8 increase of N2O emissions
- 3.1.9 increase of CO2 emissions
- 3.1.10 increase of CH4 emissions
- 3.1.11 Cumulative N2O emissions
- 3.1.12 Cumulative CO2 emissions
- 3.1.13 Cumulative CH4 emissions
- 3.1.14 Corn N2O emission coef
- 3.1.15 Soybean N2O emission coef
- 3.1.16 Wheat N2O emission coef
- 3.1.17 Corn CO2 emission coef
- 3.1.18 Soybean CO2 emission coef
- 3.1.19 Wheat CO2 emission coef
- 3.1.20 Corn CH4 emission coef
- 3.1.21 Soybean CH4 emission coef
- 3.1.22 Wheat CH4 emission coef
- 3.1.23 Inorganic fertilizer
- 3.1.24 Soil nitrogen
- 3.1.25 increase of soil N
- 3.1.26 decrease of soil N
- 3.1.27 Soil nitrogen level
- 3.1.28 Temperature
- 3.1.29 Precipitation
- 3.1.30 Pests
- 3.1.31 Tillage
- 3.1.32 Natural disasters
- 3.1.33 increase of C yield
- 3.1.34 increase of S yield
- 3.1.35 increase of W yield
- 3.1.36 Corn yield
- 3.1.37 Soybean yield
- 3.1.38 Wheat yield
- 3.1.39 Total yield
- 3.1 Variables
- 4 Results
- 5 Conclusion
- 6 Code
- 7 References
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
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
Cumulative CO2 emissions
Cumulative CH4 emissions
Corn N2O emission coef
Soybean N2O emission coef
Wheat N2O emission coef
Corn CO2 emission coef
Soybean CO2 emission coef
Wheat CO2 emission coef
Corn CH4 emission coef
Soybean CH4 emission coef
Wheat CH4 emission coef
Inorganic fertilizer
Soil nitrogen
increase of soil N
decrease of soil N
Soil nitrogen level
Temperature
Precipitation
Pests
Tillage
Natural disasters
increase of C yield
increase of S yield
increase of W yield
Corn yield
Soybean yield
Wheat yield
Total yield
=Corn yield + Soybean yield + Wheat yield
