title: how to set x axis start at 30 in bar plots
body: <p>I have water content data that starts at day 30, I would like the x axis at start at 30 when y=0.</p>
  
  <p>I have tried this codes:</p>
  
  <pre><code>bp=barplot(height=ESR18R$Rainfall,names.arg=ESR18R$DAS,las=1,xaxt="n"
             ,ylim=c(0,80),col="grey",ylab="Daily rainfall (mm)")
  
  axis(1, at = seq(30, 80, by = 10))
  </code></pre>
  
  <p>Unfortunately, this codes labels the x axis almost at the middle while I want it to start in the beginning of the x axis.</p>