title: Issue with RDA plot in R
body: <p>I am a novice in using R for multivariate analysis . I am trying to get a RDA plot depicting the relationship between my species abundance and environmental data. I have 6 environmental variables. But when I obtain the plot, I am able to see only only two vectors representing two variables alone. The commands I have used are below.</p>
  
  <pre><code>data &lt;- read.csv("all_data.csv",h=T); 
  library(vegan)
  sp1 &lt;- data[,c("Sample","Acidobacteria","Actinobacteria","Aquificae","Bacteroidetes")];
  env1 &lt;- data[,c("Nitrogen","TOC","Phosphate","Sand","Silt","Clay")];
  myrda &lt;- rda(sp1,env1)
  plot(myrda,scaling=2)
  </code></pre>
  
  <p>Someone please help me out with this. I wish to see all the 6 environmental parameters in my RDA plot.</p>