Thank you for your reply. I still have some questions though. Is this code fitting a split plot model? To identify the error terms I had on paper something like this: Block CO2 block*co2              error1 (WP error) geno co2*geno geno*block(co2)     error2 time block*time              error3 time*trt block*time*trt         error4 time*geno time*trt*geno error I understand that this is the model for a split plot design in time with whole plot in RCBD.  How do I specify the error term for each factor and interactions in the sas code? For example, test co2 with error1, test geno with error2,  test time with error 3, and so on. Similarly, how can I  determine the lsmeans given that there are different error terms? Also time cannot be randomized because these are measurements taken during five weeks, should I ignore this or is there a way to include this in the model? Thanks ... View more