title: Modify error bar
body: <p>I am trying to do two things with the following graph
  1 - Make capped error bar
  2 - Bold the error bars</p>
  
  <p><a href="https://i.stack.imgur.com/dOZtm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dOZtm.png" alt="enter image description here"></a></p>
  
  <p>This is the set of code I used</p>
  
  <pre><code>data$rotation[data$Rot.trt %in% c("C2", "S2")]&lt;-"TwoYear"
  data$rotation[data$Rot.trt %in% c("C3", "S3", "O3")]&lt;-"ThreeYear"
  data$rotation[data$Rot.trt %in% c("C4", "S4", "O4", "A4")]&lt;-"FourYear"
  
  
  ggplot(data, aes(x=Rot.Herb.label, y=kg.ha, fill=Crop))+
      geom_boxplot()+
      facet_grid(~rotation, scales = "free_x", space="free_x")+
      scale_fill_brewer(palette = "Paired")+
      theme_bw() +
      theme(panel.grid.major=element_blank())+
      ggtitle("Weed biomass by plot")+
      theme(plot.title = element_text(size=30, face="bold", vjust=2))+
      xlab("Treatment (L = Low herbicide regime, C = Conventional herbicide regime)")+
      theme(axis.text.x = element_text(size = 16, angle = 90, hjust = 1),axis.title=element_text(size=16,face="bold"))+
      ylab("Weed dry weight (kg/ha)")+
      theme(axis.text.y = element_text(size = 16))
  </code></pre>
  
  <p>As referred to <a href="http://www.cookbook-r.com/Graphs/Plotting_means_and_error_bars_(ggplot2)/" rel="nofollow noreferrer">this question</a>, I tried to add this part before the <code>geom_boxplot</code> line but it didn't help.</p>
  
  <pre><code>geom_bar(width= .1, position="dodge", color="black", stat="identity")+
  geom_errorbar(aes(ymin=kg.ha-ci, ymax=kg.ha+ci),
                width=.2,                    
  　            position=position_dodge(.9))
  </code></pre>
  
  <p>Here is what I have reached so far. 
  <a href="https://i.stack.imgur.com/qdL4W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qdL4W.png" alt="enter image description here"></a></p>
  
  <p>And here is the <a href="https://www.dropbox.com/s/hn6gwshpawo9cad/DataJul.csv?dl=0" rel="nofollow noreferrer">data</a></p>
  
  <pre><code>&gt; str(data)
  'data.frame':   72 obs. of  69 variables:
   $ Date            : Factor w/ 10 levels "10-Sep-14","12-Sep-14",..: 10 10 10 10 10 10 1 1 1 1 ...
   $ Plot            : int  11 11 13 13 18 18 23 23 24 24 ...
   $ Rep             : Factor w/ 4 levels "1rep","2rep",..: 1 1 1 1 1 1 2 2 2 2 ...
   $ Side            : Factor w/ 2 levels "E","W": 2 1 2 1 2 1 2 1 2 1 ...
   $ Crop            : Factor w/ 4 levels "alfalfa","corn",..: 2 2 2 2 2 2 2 2 2 2 ...
   $ Rot             : Factor w/ 3 levels "2rot","3rot",..: 2 2 1 1 3 3 2 2 1 1 ...
   $ Rot.Herb        : Factor w/ 18 levels "A4conv","A4low",..: 5 6 4 3 8 7 5 6 4 3 ...
   $ Rot.trt         : Factor w/ 9 levels "A4","C2","C3",..: 3 3 2 2 4 4 3 3 2 2 ...
   $ Herb.trt        : Factor w/ 2 levels "conv","low": 1 2 2 1 2 1 1 2 2 1 ...
   $ DIGSANo         : int  0 0 0 0 2 0 0 0 0 0 ...
   $ DIGSAWt         : num  0 0 0 0 1.3 0 0 0 0 0 ...
   $ SETFANo         : int  1 3 1 0 2 0 0 2 0 0 ...
   $ SETFAWt         : num  0.1 61 1.5 0 14 0 0 4.1 0 0 ...
   $ SETLUNo         : int  0 0 0 0 1 0 0 0 0 0 ...
   $ SETLUWt         : num  0 0 0 0 0.1 0 0 0 0 0 ...
   $ PANCANo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ PANCAWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ ECHCGNo         : int  0 0 0 0 6 0 0 0 0 0 ...
   $ ECHCGWt         : num  0 0 0 0 21.7 0 0 0 0 0 ...
   $ ERBVINo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ ERBVIWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ CYPESNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ CYPESWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ AMATANo         : int  0 2 8 4 2 1 1 0 1 3 ...
   $ AMATAWt         : num  0 25.5 8.3 0.1 1.2 0 0 0 0.03 1.57 ...
   $ CHEALNo         : int  6 44 0 0 0 0 0 15 2 0 ...
   $ CHEALWt         : num  0.1 208.1 0 0 0 ...
   $ SOLPTNo         : int  0 0 0 0 0 11 1 3 18 4 ...
   $ SOLPTWt         : num  0 0 0 0 0 0.4 0.08 0.3 5.81 0.17 ...
   $ PHYSUNo         : int  0 5 2 6 2 1 0 0 0 0 ...
   $ PHYSUWt         : num  0 2.1 13.9 0 0.1 0 0 0 0 0 ...
   $ POLCCNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ POLCCWt         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ POLPYNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ POLPYWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ ABUTHNo         : int  4 0 2 0 6 0 1 0 0 0 ...
   $ ABUTHWt         : num  0.2 0 0.1 0 3.1 0 0.07 0 0 0 ...
   $ TAROFNo         : int  6 4 0 21 6 3 6 7 17 33 ...
   $ TAROFWt         : num  0.1 0 0 0 0.1 0 0.07 0.23 0.18 0.51 ...
   $ EPHHTNo         : int  0 0 0 1 2 0 0 0 5 0 ...
   $ EPHHTWt         : num  0 0 0 0 0.1 0 0 0 0.13 0 ...
   $ CIRARNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ CIRARWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ SONARNo         : int  0 0 0 0 0 0 0 0 1 0 ...
   $ SONARWt         : num  0 0 0 0 0 0 0 0 0.1 0 ...
   $ MORALNo         : int  0 5 0 0 0 1 0 0 0 0 ...
   $ MORALWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ OXASTNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ OXASTWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ POLLANo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ POLLAWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ ASCSYNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ ASCSYWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ POLAVNo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ POLAVWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ PLAMANo         : int  0 0 0 0 0 0 0 0 0 0 ...
   $ PLAMAWt         : num  0 0 0 0 0 0 0 0 0 0 ...
   $ UnknowndicotNo  : int  0 0 0 0 0 0 0 0 0 0 ...
   $ UnknowndicotWt  : num  0 0 0 0 0 0 0 0 0 0 ...
   $ UnknownmonocotNo: int  0 0 0 0 0 0 0 0 0 0 ...
   $ UnknownmonocotWt: num  0 0 0 0 0 0 0 0 0 0 ...
   $ TOTALNo         : int  17 63 13 32 29 17 9 27 44 40 ...
   $ TOTALWt         : num  0.5 296.7 23.8 0.1 41.7 ...
   $ samplearea.m.2. : num  18.5 18.5 18.5 18.5 18.5 ...
   $ g.m.2           : num  0.03 16.01 1.28 0.01 2.25 ...
   $ kg.ha           : num  0.27 160.1 12.84 0.05 22.5 ...
   $ lb.acre         : num  0.24 142.97 11.47 0.05 20.09 ...
   $ rotation        : chr  "Three Year" "Three Year" "Two Year" "Two Year" ...
   $ Rot.Herb.label  : Factor w/ 8 levels "Alfalfa C","Alfalfa L",..: 3 4 4 3 4 3 3 4 4 3 ...
  </code></pre>