Why I do not get the interaction output using aov function in R I hope you are well.
I am analyzing some data related to some bacterial phylum. 
Here is the data:

I am writing the aov function as the following but I do not get the interaction value. 
acioaov <- aov(Acidobacteria ~ Treatment * Zone, data = phyla)
Why it doesn't work?
The out put of that is like the following:
Df   Sum Sq   Mean Sq F value Pr(>F)
Treatment    1 0.000106 0.0001063   0.473 0.4986
Zone         6 0.003153 0.0005255   2.338 0.0656 .
Residuals   23 0.005170 0.0002248

Thank you!
 A: If the categories of one dependent variable is associated with the categories of the other dependent variable, you'll not get the interaction.. For example, if a particular type of treatment is available in only one zone, there is no interaction between the zone and the treatment. 
Since you have not provided the information about the categories, I couldn't find any other answer for your question.
A: I cannot really type your data in, but let's suppose your data.frame phyla is something like this:
# you don't need to run
phyla = data.frame(Treatment=rep(c("NT","T"),each=4),
Zone=rep(c("maize_NT_Z1","maize_NT_Z2","maize_T_Z1","maize_T_Z2"),each=2)
)
phyla$Acidobacteria = rnorm(nrow(phyla))

summary(aov(Acidobacteria ~ Treatment * Zone, data = phyla))
            Df Sum Sq Mean Sq F value Pr(>F)  
Treatment    1  0.082  0.0824   0.319 0.6022  
Zone         2  3.391  1.6953   6.572 0.0544 .
Residuals    4  1.032  0.2580   

And you don't see the interaction term. That's because there are two categories under each zone, i.e "maize_NT_Z1" and "maize_T_Z1" are treated as a same category, but in fact, they are from the same zone Z1, so you should have maize_Z1 for both of them. Let's rectify this:
phyla$Zone = gsub("_[N]*T","",phyla$Zone)
summary(aov(Acidobacteria ~ Treatment * Zone, data = phyla))

               Df Sum Sq Mean Sq F value Pr(>F)  
Treatment       1 0.0824  0.0824   0.319 0.6022  
Zone            1 0.9381  0.9381   3.636 0.1292  
Treatment:Zone  1 2.4525  2.4525   9.507 0.0368 *
Residuals       4 1.0318  0.2580                 

A: Do you have more than one observation for each combination of Treatment and Zone? (Unless you do, you cannot estimated the interaction terms in the aabsence of additional assumptions.) Is your data balanced?
