The SWAP Model

The SWAP Model preview image

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Pj Peter Johnson (Author)

Tags

conservation 

Tagged by Peter Johnson almost 5 years ago

farmer behaviour 

Tagged by Peter Johnson almost 5 years ago

farming 

Tagged by Peter Johnson almost 5 years ago

soil and water conservation 

Tagged by Peter Johnson almost 5 years ago

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breed          [ farmers farmer ]
breed          [ extension-agents extension-agent ]

patches-own    [ soil-quality                       ;; score, normally distributed
                 soil-conservation-practised        ;; ?, false, true
                 owned-by                           ;; which turtle (farmer) owns the field
                 ]                                  
                 

farmers-own [    soil-conservation-decision         ;; not_accepted, accepted_not_adopted, adopted
                 acceptance-decision-score          ;; 0 = start, 1 = symptoms recognised, 2 = effects recognised, 3 = taken 
                                                    ;; serious, 4 = aware of methods, 5 = able to undertake, 6 = willing to 
                                                    ;; undertake, 7 = ready to unertake, 8 = accepted
                                  
              ;; household characteristics
                
                 age-of-decision-maker              ;; yrs, initially normally distributed
                 education-of-decision-maker        ;; normally distributed
                                  
                 successor                          ;; ?, Y/N, true / false
                 
                 decision-maker-does-labouring      ;; ?, Y/N, true / false
                 
                 size-of-household                  ;; ppl, normally distributed
  
              ;; economic attributes
                 
                 land-tenure-status                 ;; owned or rented
                 labour-access                      ;; ?, Y/N, true or false
                 credit-access                      ;; ?, Y/N, true or false
                 number-of-fields-owned             ;; No. of patches a farmer agent owns/rents
                 
                 
                 income                             ;; = no. of fields owned * soil quality of fields owned * knowledge of land
                 savings                            ;; normally distributed
                 consumption-requirement            ;; = size of household * consumption-reqiurement-per-individual
                 
                 risk-aversion                      ;; score, normally distributed
                 discount-rate                      ;; normally distributed
              
              ;; social attributes
              
                 cultural-inertia                   ;; score, normally distributed 
                 adherence-to-norms                 ;; score, normally distributed 
                 institution-attitude               ;; score, normally distributed 
                 influence-score                    ;; score, normally distributed 
              
              
              ;; other attributes
  
                 knowledge-of-land                  ;; same as age
                 knowledge-of-technology            ;; score, normally distributed 
                 extension-worker-contact           ;; ?, Y/N, ture of false,
                 
                 my-farm                            ;; group of patches owned by a turtle
                 
                 average-soil-quality-of-farm       ;; mean soil quality of my farm
                 
                 timeHadSWC                         ;; steps a farmer has practised SWC
                 timesDisadopted                    ;; count times a farmer disadopts
                 
                 %OfMyFarmwithSWC                   ;; % of patches of a farm with SWC
                 
                 ]
             
globals        [ number-of-shock-weather-events     ;; count shock weather events
                 decisions-to-accept                ;; count acceptance decisions
                 decisions-to-adopt                 ;; count adoption decisions
                 decisions-to-stop-adoption         ;; count disadoption decisions
                 case-study-name                    ;; case study name monitor
                 
                 IoD                                ;; Index of dissimilarity and its calculation (4 quadrants)
                 DareaA
                 DareaB
                 DareaC
                 DareaD
               
                  ]  
   
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;;;; load case study data for ease of use and 'playing'

to CasestudyTigray
  
   set average-age-of-decision-maker 47
   set average-years-of-education 4.79
   set average-size-of-household 4.6
   set average-savings 100
   set consumption-per-individual 200
   set average-risk-aversion 50
   set average-discount-rate 0.15
   set average-cultural-inertia 50
   set average-adherence-to-norms 59.4
   set average-institutional-attitude 50
   set average-influence-score 50
   set average-knowledge-of-tech 50
   set inital-proportion-farmers-practising-conservation 0.1
   set proportion-of-households-with-successor 0.422
   set proportion-of-households-with-decision-maker-labourer 0.9
   set proportion-of-households-own-land 0.75
   set proportion-of-households-with-labour-access 0.2
   set proportion-of-households-with-credit-access 0.1
   set proportion-of-households-with-extension-contact 0.574
   set death-age 60.5
   set case-study-name "Tigray"
   
   ;; different calibrated values for last two interaction types
   
   if interaction-types = "extension worker" [   set average-institutional-attitude 30 
                                                 set average-risk-aversion 75
                                                 set average-discount-rate 0.4
                                                 set average-cultural-inertia 80
                                                 set average-influence-score 30
                                                 set average-knowledge-of-tech 20 ]
   
   if interaction-types = "all"              [   set average-institutional-attitude 15 
                                                 set average-risk-aversion 90
                                                 set average-discount-rate 0.5
                                                 set average-cultural-inertia 90
                                                 set average-influence-score 15
                                                 set average-knowledge-of-tech 15 ]
end 

to CaseStudySENigeria
  
   set average-age-of-decision-maker 54.6
   set average-years-of-education 7.01
   set average-size-of-household 4.52
   set average-savings 100
   set consumption-per-individual 200
   set average-risk-aversion 50
   set average-discount-rate 0.15
   set average-cultural-inertia 50
   ifelse random 10 > 4 [ set average-adherence-to-norms 40 ] [ set average-adherence-to-norms 60 ]
   set average-institutional-attitude 50
   set average-influence-score 50
   set average-knowledge-of-tech 50
   set inital-proportion-farmers-practising-conservation 0.1
   ifelse random 10 > 4 [ set proportion-of-households-with-successor 0.4 ]
                        [ set proportion-of-households-with-successor 0.6 ]
   set proportion-of-households-with-decision-maker-labourer 0.73
   set proportion-of-households-own-land 0.61
   set proportion-of-households-with-labour-access 0.745
   set proportion-of-households-with-credit-access 0.204
   set proportion-of-households-with-extension-contact 0.33
   set death-age 53
   set case-study-name "SE Nigeria"
   
   ;; different calibrated values for last two interaction types
   
   if interaction-types = "extension worker" [   set average-institutional-attitude 30 
                                                 set average-risk-aversion 75
                                                 set average-discount-rate 0.4
                                                 set average-cultural-inertia 80
                                                 set average-influence-score 30
                                                 set average-knowledge-of-tech 20 ]
   
   if interaction-types = "all"              [   set average-institutional-attitude 15 
                                                 set average-risk-aversion 90
                                                 set average-discount-rate 0.5
                                                 set average-cultural-inertia 90
                                                 set average-influence-score 15
                                                 set average-knowledge-of-tech 15 ]
end 

to caseStudyCebu
  
   set average-age-of-decision-maker 48.2
   set average-years-of-education 4.4
   set average-size-of-household 4.8
   set average-savings 100
   set consumption-per-individual 200
   set average-risk-aversion 50
   set average-discount-rate 0.15
   set average-cultural-inertia 50
   if random 3 = 2 [ set average-adherence-to-norms 40 ] 
   if random 3 = 1 [ set average-adherence-to-norms 50 ]
   if random 3 = 0 [ set average-adherence-to-norms 60 ]
   set average-institutional-attitude 50
   set average-influence-score 50
   set average-knowledge-of-tech 50
   set inital-proportion-farmers-practising-conservation 0.1
   ifelse random 10 > 4 [ set proportion-of-households-with-successor 0.4 ]
                        [ set proportion-of-households-with-successor 0.6 ]
   ifelse random 10 > 4 [ set proportion-of-households-with-decision-maker-labourer 0.6 ] 
                        [ set proportion-of-households-with-decision-maker-labourer 0.9 ] 
   set proportion-of-households-own-land 0.45
   set proportion-of-households-with-labour-access 0.3
   set proportion-of-households-with-credit-access 0.3
   set proportion-of-households-with-extension-contact 0.08
   set death-age 73
   set case-study-name "Cebu"
   
   ;; different calibrated values for last two interaction types
   
   if interaction-types = "extension worker" [   set average-institutional-attitude 30 
                                                 set average-risk-aversion 75
                                                 set average-discount-rate 0.4
                                                 set average-cultural-inertia 80
                                                 set average-influence-score 30
                                                 set average-knowledge-of-tech 20 ]
   
   if interaction-types = "all"              [   set average-institutional-attitude 15 
                                                 set average-risk-aversion 90
                                                 set average-discount-rate 0.5
                                                 set average-cultural-inertia 90
                                                 set average-influence-score 15
                                                 set average-knowledge-of-tech 15 ]
end 

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to setup
  
  clear-all
  setup-patches-and-create-turtles
  set-farmer-attributes
  set-case-study-name
  my-update-plots
  reset-ticks
end 

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to go
  
  farmer-decision-start-point
  extension-agents-move
  update-patches 
  update-attributes
  ask farmers with [ soil-conservation-decision = "adopted" ] [ set timeHadSWC timeHadSWC + 1 ]
  IoDiss
  tick
  my-update-plots
end 

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to setup-patches-and-create-turtles
  
  ;; creating pathes and turtles
  
  ask patches [
    
    ;; set initial soil quality
    
    set soil-quality random-normal 25 10
    
    let my-area patches in-radius 1
    
    if ( mean [ soil-quality ] of my-area ) > soil-quality [ set soil-quality soil-quality + 5 ]
    if ( mean [ soil-quality ] of my-area ) < soil-quality [ set soil-quality soil-quality - 5 ] 
    
    ;; set initial practice
    
    set soil-conservation-practised false 
    
    ;; set patch colors, brown no conservation, green conservation, 
    ;; darker shade means higher quality, lighter means lower quality
           
    if ( soil-quality < 25 ) and ( soil-conservation-practised = true ) [ set pcolor 59 ]
    if ( soil-quality >= 25 ) and ( soil-quality < 50 ) and ( soil-conservation-practised = true ) [ set pcolor 57 ]
    if ( soil-quality >= 50 ) and ( soil-quality < 75 ) and ( soil-conservation-practised = true ) [ set pcolor 54 ]
    if soil-quality >= 75 and (soil-conservation-practised = true ) [ set pcolor 52 ]
    
    if ( soil-quality < 25 ) and ( soil-conservation-practised = false ) [ set pcolor 39 ]
    if ( soil-quality >= 25 ) and ( soil-quality < 50 ) and ( soil-conservation-practised = false ) [ set pcolor 37 ]
    if ( soil-quality >= 50 ) and ( soil-quality < 75 ) and ( soil-conservation-practised = false ) [ set pcolor 34 ]
    if soil-quality >= 75 and (soil-conservation-practised = false ) [ set pcolor 32 ]
    ]

  ;;  create population
  
  ;;  create new agents, spread randomly, set appearance ( extension agents first )
  
  if ( interaction-types = "extension worker" ) or ( interaction-types = "all" ) 
  
                                [ create-extension-agents ( number-of-initial-farmers / 20 )  [                         
                                  setxy random-pxcor random-pycor
                                  set shape "triangle"
                                  set color red 
                                  set size 1.5
  ]]
                                  create-farmers number-of-initial-farmers  [ 
                                  setxy random-pxcor random-pycor
                                  if any? other farmers-here [ move-to one-of patches with [ not any? farmers-here ] ]
                                  set shape "circle"
                                  set color red 
                                  set size 1]
                                  
                                  ;; turtle owns patches it's nearest to
  
                                  ask patches 
                                  
                                [ set owned-by min-one-of farmers [distance myself] ] 
end 

;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;; 
;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;;
;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;; setting farmers attributes;;

to set-farmer-attributes
  
;; setup farmer parameters, using case study data for a mean of normal distribution, SD set at a plausible level

ask farmers [ 
  
              ;; basics for outputs
              
              set timeHadSWC 0
              set timesDisadopted 1 ;; set at 1 to avoid division by zero when used in outputs/plots
              
              ;; score based parameters
                                  
              set age-of-decision-maker random-normal average-age-of-decision-maker 10
              set education-of-decision-maker random-normal average-years-of-education 3
              set size-of-household random-normal average-size-of-household 3
                                  
              set number-of-fields-owned count patches with [ owned-by = myself ]                                  
              set my-farm patches with [ owned-by = myself ]
                                  
              set income 
              (  ( number-of-fields-owned *  mean [ soil-quality ] of my-farm ) + knowledge-of-land )
                                  
              set savings random-normal average-savings 40 
              set consumption-requirement ( size-of-household * consumption-per-individual ) 
                                                   
              set risk-aversion random-normal average-risk-aversion 20 
              ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                [ set risk-aversion risk-aversion - 30 ] )
              set discount-rate random-normal average-discount-rate 0.07
                                  
              set cultural-inertia random-normal average-cultural-inertia 20 
              ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                [ set cultural-inertia cultural-inertia - 30 ] )
              set adherence-to-norms random-normal average-adherence-to-norms 20
              set institution-attitude random-normal average-institutional-attitude 20 
              ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                [ set institution-attitude institution-attitude  + 30 ] )
              set influence-score random-normal average-influence-score 20
  
              set knowledge-of-land age-of-decision-maker 
              set knowledge-of-technology random-normal average-knowledge-of-tech 20 
              ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                [ set knowledge-of-technology knowledge-of-technology - 30 ] )
                                  
              set average-soil-quality-of-farm mean [ soil-quality ] of my-farm
                                  
              set soil-conservation-decision "not_accepted"  ]
                                  
              ;; some farmers already practise SC
                                  
              ask n-of ( inital-proportion-farmers-practising-conservation * count farmers ) farmers 
                [ set soil-conservation-decision "adopted" 
                  set color black ask n-of (0.5 * count my-farm) my-farm 
                       [ set soil-conservation-practised true 
                         if ( soil-quality < 25 ) and ( soil-conservation-practised = true ) 
                              [ set pcolor 59 ]
                         if ( soil-quality >= 25 ) and ( soil-quality < 50 ) and ( soil-conservation-practised = true ) 
                              [ set pcolor 57 ]
                         if ( soil-quality >= 50 ) and ( soil-quality < 75 ) and ( soil-conservation-practised = true ) 
                              [ set pcolor 54 ]
                         if soil-quality >= 75 and ( soil-conservation-practised = true ) 
                              [ set pcolor 52 ]
                              ] ] 
                                  
              ask farmers [ if soil-conservation-decision = "not_accepted" [ set acceptance-decision-score 0 ]
                            if soil-conservation-decision = "accepted_not_adopted" [ set acceptance-decision-score 7 ]
                            if soil-conservation-decision = "adopted" [ set acceptance-decision-score 7 ] 
                                  
                                  ] 
                               
              ;; proportion Y/N parameters
                                                                                                                                
              ask farmers [ set successor false ]
                                  
              ask n-of ( proportion-of-households-with-successor * count farmers ) farmers [ set successor true ]
                                  
              ask farmers [ set decision-maker-does-labouring false ]
                                  
              ask n-of ( proportion-of-households-with-decision-maker-labourer * count farmers ) farmers 
              [ set decision-maker-does-labouring true ]
                                   
              ask farmers [ set land-tenure-status "rented" ]
                                  
              ask n-of ( proportion-of-households-own-land * count farmers ) farmers 
              [ set land-tenure-status "owned" ]
                                  
              ask farmers [ set labour-access false ]
                                  
              ask n-of ( proportion-of-households-with-labour-access * count farmers ) farmers 
              [ set labour-access true ]
                                  
              ask farmers [ set credit-access false ]
                                  
              ask n-of ( proportion-of-households-with-credit-access * count farmers ) farmers 
              [ set credit-access true ]
                                  
              ask farmers [ set extension-worker-contact false ]
                                  
              ask n-of ( proportion-of-households-with-extension-contact * count farmers ) farmers 
              [ set extension-worker-contact true ]
end  

;; double checking labelling of run using death age

to set-case-study-name
  if death-age = 60.5 [ set case-study-name "Tigray" ]
  if death-age = 53 [ set case-study-name "SE Nigeria" ]
  if death-age = 73 [ set case-study-name "Cebu" ]
end 


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;; farmers have to start their decision in right place each tick so...

to farmer-decision-start-point
  ask farmers [ if soil-conservation-decision = "not_accepted" OR soil-conservation-decision = "accepted_not_adopted" 
    [ ask my-farm [ set soil-conservation-practised false ] ] ]
  
  ask farmers [ if any? my-farm with [ soil-conservation-practised = true ] [ run-continued-use-decision]
                if not any? my-farm with [ soil-conservation-practised = true ] [ run-decide-between-accept-and-adopt ]]
end 

;; farmers current 'opinion' affects which decision procedure to now run

to run-decide-between-accept-and-adopt
  
       if soil-conservation-decision = "not_accepted" [ run-acceptance-decision  ]
       if soil-conservation-decision = "accepted_not_adopted" [ run-adoption-decision ]
       if soil-conservation-decision = "adopted" [ run-continued-use-decision ]
end 

;; choose which stage of acceptance decision to run according to current 'opinion'

to run-acceptance-decision 
  
 ;; 10% probability of accepting need for SWC by chance
  
 ifelse random 100 > 89 [ accept-conservation ] [
 if acceptance-decision-score = 0 [ degradation-symptoms-recognised ]
 if acceptance-decision-score = 1 [ degradation-effects-recognised  ]
 if acceptance-decision-score = 2 [ degradation-taken-serious ]
 if acceptance-decision-score = 3 [ aware-of-conservation-methods ]
 if acceptance-decision-score = 4 [ able-to-undertake-conservation ]
 if acceptance-decision-score = 5 [ willing-to-undertake-conservation ]
 if acceptance-decision-score = 6 [ ready-to-undertake-conservation ]
 if acceptance-decision-score = 7 [ accept-conservation ]
 ]
end 

;; the following 8 procedures are the acceptance decision process

to degradation-symptoms-recognised
           
           let deg-symp-recog ( ( 100 - soil-quality ) + knowledge-of-land )
           
           if  ( deg-symp-recog > 100 ) and ( decision-maker-does-labouring = true ) 
           [ set acceptance-decision-score  1 ]
end 

to degradation-effects-recognised          
           
            let deg-eff-recog 
            (( 100 - age-of-decision-maker ) + knowledge-of-land + education-of-decision-maker + ( 100 - cultural-inertia ))
            
            if  ( deg-eff-recog > 125 ) and ( extension-worker-contact = true ) 
            [ set acceptance-decision-score 2 ] 
end 

to degradation-taken-serious
 
            if (  extension-worker-contact = true ) and ( land-tenure-status = "owned" ) [ set acceptance-decision-score 3 ]
end 

to aware-of-conservation-methods
 
            if ( knowledge-of-technology > 60 ) and (  extension-worker-contact = true ) [ set acceptance-decision-score 4 ]
end 

to able-to-undertake-conservation

            if ( age-of-decision-maker < 75 ) and ( labour-access = true ) and 
               (  extension-worker-contact = true ) and ( credit-access = true ) and ( land-tenure-status = "owned" ) 
               [ set acceptance-decision-score 5 ]
               
            if ( age-of-decision-maker < 75 ) and ( size-of-household > 3 )  and 
               (  extension-worker-contact = true ) and ( credit-access = true ) and ( land-tenure-status = "owned" ) 
               [ set acceptance-decision-score 5 ]
               
            if ( age-of-decision-maker < 75 ) and ( labour-access = true ) and 
               (  extension-worker-contact = true ) and ( savings > 75 ) and ( land-tenure-status = "owned" ) 
               [ set acceptance-decision-score 5 ]
               
            if ( age-of-decision-maker < 75 ) and ( size-of-household > 3 )  and 
               (  extension-worker-contact = true ) and ( savings > 75 ) and ( land-tenure-status = "owned" ) 
               [ set acceptance-decision-score 5 ]
end 

to willing-to-undertake-conservation

            let willing 
            ((  100 - ( discount-rate * 100 ) ) + ( 100 - cultural-inertia ) + 
              institution-attitude + ( 100 - age-of-decision-maker ))
              
            if ( willing > 100 ) and ( successor = true ) and ( decision-maker-does-labouring = true ) 
            [ set acceptance-decision-score 6 ]
end 

to ready-to-undertake-conservation

            let ready ( ( 100 - risk-aversion ) + savings + income )
            
            if ( ready > 200 ) [ set acceptance-decision-score 7 ]
end 

to accept-conservation

    set soil-conservation-decision "accepted_not_adopted"
    set decisions-to-accept decisions-to-accept + 1
    set color blue
    ask my-farm [set soil-conservation-practised false ]
end 

;; adoption decision - run once acceptance is true

to run-adoption-decision
  
  if ( risk-aversion > 80 ) 
      
          [ set soil-conservation-decision "accepted_not_adopted" 
            set color blue ask my-farm [ set soil-conservation-practised false ] ]                                    
                        
  if ( risk-aversion > 60 ) and ( risk-aversion <= 80 ) and (  extension-worker-contact = true )
  
          [ set soil-conservation-decision "adopted" 
            set color black 
            set decisions-to-adopt decisions-to-adopt + 1 
            ask n-of ( 0.1 * count my-farm ) my-farm [ set soil-conservation-practised true ]]
  
  if ( risk-aversion > 40 ) and ( risk-aversion <= 60 ) and (  extension-worker-contact = true )
  
          [ set soil-conservation-decision "adopted" 
            set color black 
            set decisions-to-adopt decisions-to-adopt + 1 
            ask n-of ( 0.25 * count my-farm ) my-farm [ set soil-conservation-practised true ]]
 
  if ( risk-aversion > 20 ) and ( risk-aversion <= 40 ) and (  extension-worker-contact = true ) 
  
          [ set soil-conservation-decision "adopted" 
            set color black 
            set decisions-to-adopt decisions-to-adopt + 1 
            ask n-of ( 0.5 * count my-farm ) my-farm [ set soil-conservation-practised true ]]
  
  if ( risk-aversion <= 20 ) and (  extension-worker-contact = true )
  
          [ set soil-conservation-decision "adopted" 
            set color black 
            set decisions-to-adopt decisions-to-adopt + 1 
            ask n-of ( 0.75 * count my-farm ) my-farm [ set soil-conservation-practised true ]]
end 

;; contined use decision

to run-continued-use-decision
  
  ;; increase or reduce adoption dependent on results ie., income
  
  if ( income > consumption-requirement ) 
  [ ask n-of ( 0.2 * count my-farm with [ soil-conservation-practised = false ] ) 
    my-farm with [ soil-conservation-practised = false ] 
    [ set soil-conservation-practised  true  ] ]
  
  if ( income < consumption-requirement ) 
  [ ask n-of ( 0.2 * count my-farm with [ soil-conservation-practised = true ] ) 
    my-farm with [ soil-conservation-practised = true ]  
    [ set soil-conservation-practised false ] ]
  
  
 ;; if very low adoption, stop altogether
  
  if ( soil-conservation-decision = "adopted" ) and 
  ( count my-farm with  [ soil-conservation-practised = true ] < ( 0.1 * count my-farm )) 
  
  [ set soil-conservation-decision "accepted_not_adopted" 
    set color blue 
    set decisions-to-stop-adoption decisions-to-stop-adoption + 1  
    set timesDisadopted timesDisadopted + 1
    ask my-farm [ set soil-conservation-practised false ] ]
end 

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;; extension agents have to move so...

to extension-agents-move
  
  if ( interaction-types = "extension worker" ) or ( interaction-types = "all" ) 
  [ ask extension-agents [ set heading random 360 fd 10 ] ]
end 

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;;;;;;;;;;;;;;;;;;;;;UPDATE VARIABLES;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;UPDATE VARIABLES;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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to update-patches
  
                ;; chance of shock weather event
  
                if random-float 100 < 4 [  set number-of-shock-weather-events number-of-shock-weather-events + 1
                                           ask patches 
                                           [ set soil-quality soil-quality - (( random-normal 0.5 0.1 ) * soil-quality ) ]]
                
  
  ask patches [ ;; random noise in soil quality
    
                ifelse random 2 = 1 [ set soil-quality soil-quality + 5.8 ] [ set soil-quality soil-quality - 5 ] 
                        
                ;; effect of conservation
                
                if ( soil-conservation-practised = true ) [ set soil-quality soil-quality + 8 ] 
                
                if ( soil-conservation-practised = false ) [ set soil-quality soil-quality - 1 ] 
               ]
                 
                ;; fields around a field affect it 
                
  ask patches [ let my-area patches in-radius 1
    
                if ( mean [ soil-quality ] of my-area ) > soil-quality [ set soil-quality soil-quality + 5 ]
                if ( mean [ soil-quality ] of my-area ) < soil-quality [ set soil-quality soil-quality - 5 ] 
                
                ;; regulate scores within 0-100
                
                if soil-quality > 100 [ set soil-quality 95 ]  
                if soil-quality < 0 [ set soil-quality 5 ]               
                 
                ;; update colour of patches each tick 
                  
                if ( soil-quality < 25 ) and ( soil-conservation-practised = true ) 
                [ set pcolor 59 ]
                if ( soil-quality >= 25 ) and ( soil-quality < 50 ) and ( soil-conservation-practised = true ) 
                [ set pcolor 57 ]
                if ( soil-quality >= 50 ) and ( soil-quality < 75 ) and ( soil-conservation-practised = true ) 
                [ set pcolor 54 ]
                if soil-quality >= 75 and ( soil-conservation-practised = true ) 
                [ set pcolor 52 ]
    
                if ( soil-quality < 25 ) and ( soil-conservation-practised = false ) 
                [ set pcolor 39 ]
                if ( soil-quality >= 25 ) and ( soil-quality < 50 ) and ( soil-conservation-practised = false ) 
                [ set pcolor 37 ]
                if ( soil-quality >= 50 ) and ( soil-quality < 75 ) and ( soil-conservation-practised = false ) 
                [ set pcolor 34 ]
                if soil-quality >= 75 and ( soil-conservation-practised = false ) 
                [ set pcolor 32 ]
  ]
end 

to update-attributes 
  
  ;; update income, consumption req, contact with ext, age, knowledge of land, knowledge of tech
  
  ask farmers [ 
    
                ;; calc prop of my farm with SWC
                
                set %OfMyFarmwithSWC round 
                ((( count my-farm with [ soil-conservation-practised = true ] ) / (count my-farm )) * 100 ) 
                
                ;; age and knowledge of land go up with time
    
                set age-of-decision-maker age-of-decision-maker + 0.25
                set knowledge-of-land age-of-decision-maker
                
                ;; update farm soil quality and income
                
                set average-soil-quality-of-farm mean [ soil-quality ] of my-farm
                set income  ( number-of-fields-owned *  mean [ soil-quality ] of my-farm ) + knowledge-of-land 
                
                ;; spatial / locality effects
                
                local-effects    ;; below - these are the interaction types
                
                ;; death - if have a successor all attributes stay same except age, 
                ;; if no successor, all change, soil cons decision will be back to not accepted
                
                if ( age-of-decision-maker > ( death-age * random-normal 1 0.2 ) ) and ( successor = true ) 
                [ set age-of-decision-maker 20 
                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-successor  
                  [ set successor false ] [set successor true ]] 
                
                
                if ( age-of-decision-maker > ( death-age * random-normal 1 0.2 ) ) and ( successor = false ) [ 
                  
                                  set age-of-decision-maker random-normal average-age-of-decision-maker 10
                                  set education-of-decision-maker random-normal average-years-of-education 3
                                  set size-of-household random-normal average-size-of-household 3
                                  
                                  set number-of-fields-owned count patches with [ owned-by = myself ]                                  
                                  set my-farm patches with [ owned-by = myself ]
                                  
                                  set income 
                                  ( number-of-fields-owned *  mean [ soil-quality ] of my-farm ) + knowledge-of-land
                                  
                                  set savings random-normal average-savings 40 
                                  set consumption-requirement ( size-of-household * consumption-per-individual )  
                                                   
                                  set risk-aversion random-normal average-risk-aversion 20 
                                  ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                                    [ set risk-aversion risk-aversion - 30 ] )
                                  set discount-rate random-normal average-discount-rate 0.07
                                  
                                  set cultural-inertia random-normal average-cultural-inertia 20 
                                  ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                                    [ set cultural-inertia cultural-inertia - 30 ] )
                                  set adherence-to-norms random-normal average-adherence-to-norms 20
                                  set institution-attitude random-normal average-institutional-attitude 20 
                                  ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                                    [ set institution-attitude institution-attitude  + 30 ] )
                                  set influence-score random-normal average-influence-score 20
  
                                  set knowledge-of-land age-of-decision-maker 
                                  set knowledge-of-technology random-normal average-knowledge-of-tech 20 
                                  ( if ( age-of-decision-maker < average-age-of-decision-maker ) 
                                    [ set knowledge-of-technology knowledge-of-technology - 30 ] )
                                  
                                  set average-soil-quality-of-farm mean [ soil-quality ] of my-farm
                                  
                                  set soil-conservation-decision "not_accepted" 
                                  set timesDisadopted timesDisadopted + 1
                                  set color red
                                                                            
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-successor  
                                  [ set successor false ] [set successor true ]
                                  
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-decision-maker-labourer 
                                  [ set decision-maker-does-labouring false ] [set decision-maker-does-labouring true ]
                                  
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-own-land 
                                  [ set land-tenure-status "rented" ] [set land-tenure-status "owned" ]
                                  
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-labour-access 
                                  [ set labour-access false ] [set labour-access true ]
                                  
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-credit-access 
                                  [ set credit-access false ] [set credit-access true ]
                               
                                  ifelse ( random-float 1 + 0.00001 ) > proportion-of-households-with-extension-contact 
                                  [ set extension-worker-contact false ] [set extension-worker-contact true ] 
  ]
             
  ]
end 

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;interaction effects;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to local-effects
  
                if interaction-types = "farmer groups" [ farmer-groups ]
                if interaction-types = "influential individuals" [ influential-individuals ]
                if interaction-types = "extension worker" [ extension-worker ]
                if interaction-types = "all" [ all-local-effects ]
end 

to farmer-groups
  
                ;; if farmer effects turned on, and any or all of my group are using SC, and i have adherence to norms above 30, 
                ;; then 'increase' some variables and thus chance of adoption / acceptance
                   
                let my-farmer-group farmers in-radius 10  
                
                if ( adherence-to-norms > 50 ) and ( any? my-farmer-group with [ soil-conservation-decision = "adopted" ]  ) 
                           
                           [ set knowledge-of-technology knowledge-of-technology + ( 0.2 * knowledge-of-technology ) 
                             set risk-aversion risk-aversion - ( 0.2 * risk-aversion )
                             set cultural-inertia cultural-inertia - ( 0.2 * cultural-inertia )
                              ]
                
                if (adherence-to-norms > 50 ) and ( all? my-farmer-group [ soil-conservation-decision = "adopted" ] )
                
                           [ set knowledge-of-technology knowledge-of-technology + ( ( 2 * 0.2 ) * knowledge-of-technology ) 
                             set risk-aversion risk-aversion - ( ( 2 * 0.2 ) * risk-aversion )
                             set cultural-inertia cultural-inertia - ( ( 2 * 0.2 ) * cultural-inertia )
                              ]
                           
                if ( soil-conservation-decision = "not_accepted" ) and 
                  (( count my-farmer-group with [ soil-conservation-decision = "adopted" ]) > 
                    ( 0.75 * count my-farmer-group )) and ( adherence-to-norms > 50 )
                
                      [ set soil-conservation-decision "accepted_not_adopted" 
                        set color blue 
                        set decisions-to-accept decisions-to-accept + 1 
                        ask my-farm [ set soil-conservation-practised false 
                        ]]
end 

to influential-individuals
  
  ;; like a leader some agents have very high influence over others in their group- 
  ;; others will  take on their scores - like a leader
  
  let my-farmer-group farmers in-radius 10 
  
  if influence-score > 80 [ ask my-farmer-group [ 
      
                             set knowledge-of-technology [ knowledge-of-technology ] of myself 
                             set risk-aversion [ risk-aversion ] of myself
                             set cultural-inertia [ cultural-inertia ] of myself
      
  ]]
end 

to extension-worker
  
  ;; extension agents roam around randomly and set new scores for farmers..
  
  if any? extension-agents in-radius 1
  
  [                          set knowledge-of-technology knowledge-of-technology + ( 0.3 * knowledge-of-technology )  
                             set risk-aversion risk-aversion - ( 0.3 * risk-aversion )
                             set cultural-inertia cultural-inertia - ( 0.3 * cultural-inertia )
                             set extension-worker-contact true
                             
                             if ( random 4 >= 2 ) and ( soil-conservation-decision = "not_accepted" ) 
                             [ set soil-conservation-decision "accepted_not_adopted" 
                               set color blue 
                               set decisions-to-accept decisions-to-accept + 1 
                               ask my-farm [set soil-conservation-practised false ]]
  ]
end 

to all-local-effects
  
  let my-farmer-group farmers in-radius 10  
                
                if ( adherence-to-norms > 50 ) and ( any? my-farmer-group with [ soil-conservation-decision = "adopted" ]  ) 
                           
                           [ set knowledge-of-technology knowledge-of-technology + ( 0.2 * knowledge-of-technology ) 
                             set risk-aversion risk-aversion - ( 0.2 * risk-aversion )
                             set cultural-inertia cultural-inertia - ( 0.2 * cultural-inertia )
                              ]
                
                if (adherence-to-norms > 50 ) and ( all? my-farmer-group [ soil-conservation-decision = "adopted" ] )
                
                           [ set knowledge-of-technology knowledge-of-technology + ( ( 2 * 0.2 ) * knowledge-of-technology ) 
                             set risk-aversion risk-aversion - ( ( 2 * 0.2 ) * risk-aversion )
                             set cultural-inertia cultural-inertia - ( ( 2 * 0.2 ) * cultural-inertia )
                              ]
                           
                if ( soil-conservation-decision = "not_accepted" ) and 
                (( count my-farmer-group with [ soil-conservation-decision = "adopted" ]) > 
                  ( 0.75 * count my-farmer-group )) and ( adherence-to-norms > 50 ) 
                
                   [ set soil-conservation-decision "accepted_not_adopted" 
                     set color blue 
                     set decisions-to-accept decisions-to-accept + 1 
                     ask my-farm [set soil-conservation-practised false ] ]     
  
  if influence-score > 80 [ ask my-farmer-group [ 
      
                             set knowledge-of-technology [ knowledge-of-technology ] of myself 
                             set risk-aversion [ risk-aversion ] of myself
                             set cultural-inertia [ cultural-inertia ]  of myself ] ]
  
  if any? extension-agents in-radius 1
  
  [                          set knowledge-of-technology knowledge-of-technology + ( 0.6 * knowledge-of-technology )  
                             set risk-aversion risk-aversion - ( 0.6 * risk-aversion )
                             set cultural-inertia cultural-inertia - ( 0.6 * cultural-inertia )
                             set extension-worker-contact true
                             
                             if ( random 4 >= 2 ) and ( soil-conservation-decision = "not_accepted" ) 
                             [ set soil-conservation-decision "accepted_not_adopted" 
                               set color blue 
                               set decisions-to-accept decisions-to-accept + 1 
                               ask my-farm [set soil-conservation-practised false ]]
                               ]
end 

;;;;;;;;;;;;;;;;;;;;;;;;;;PLOTS;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;PLOTS;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

to my-update-plots
  
  set-current-plot "percentage of fields with SWC"
  set-current-plot-pen "percentage of fields with conservation"
  plot ((  ( count patches with [ soil-conservation-practised = true ])  / count patches ) * 100 )
  
  
  set-current-plot "percentage of farmers adopted SWC"
  set-current-plot-pen "default"
  plot (( count farmers with [ soil-conservation-decision = "adopted" ] ) / count farmers ) * 100
end 


;;;;;;;;;;;;;;;;;;;;;;;;index of dissimilarity;;;;;;;;;;;

to IoDiss
  ; D = 0.5(abs)sum(b/B - w/W), over the 4 areas.
   
   set DareaA ( ( count farmers with [ xcor >= 0 and ycor >= 0 and soil-conservation-decision = "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision = "adopted" ] )) - 
              ( ( count farmers with [ xcor >= 0 and ycor >= 0 and soil-conservation-decision != "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision != "adopted" ] ))
              
   set DareaB ( ( count farmers with [ xcor >= 0 and ycor < 0 and soil-conservation-decision = "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision = "adopted" ] )) - 
              ( ( count farmers with [ xcor >= 0 and ycor < 0 and soil-conservation-decision != "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision != "adopted" ] ))
              
   set DareaC ( ( count farmers with [ xcor < 0 and ycor < 0 and soil-conservation-decision = "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision = "adopted" ] )) - 
              ( ( count farmers with [ xcor < 0 and ycor < 0 and soil-conservation-decision != "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision != "adopted" ] ))
              
   set DareaD ( ( count farmers with [ xcor < 0 and ycor >= 0 and soil-conservation-decision = "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision = "adopted" ] )) - 
              ( ( count farmers with [ xcor < 0 and ycor >= 0 and soil-conservation-decision != "adopted" ] ) / 
                ( count farmers with [ soil-conservation-decision != "adopted" ] ))
              
   
   set IoD 0.5 * ( abs DareaA + abs DareaB + abs DareaC + abs DareaD ) 
end 

There are 6 versions of this model.

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Peter Johnson over 4 years ago 20oct Download this version
Peter Johnson over 4 years ago More INFO tab updates Download this version
Peter Johnson over 4 years ago Further tidying Download this version
Peter Johnson over 4 years ago Updated interface Download this version
Peter Johnson almost 5 years ago Tidied code for width Download this version
Peter Johnson almost 5 years ago Initial upload Download this version

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