Hello All, I am working with a fertilizer study in apple tree production and I am hoping to get some help regarding my code. Experimental Design: RCBD with 4 blocks (rows) 3 trees per plot (row*trt) 5 Treatments (fertilizer rates) = (0, 25, 50, 75, and 100 lbs N/acre) Measured Yield per tree once every 3 years (2019-2021) My main interest is in differences per treatments, but I would also like to see how they are affected by time. I have gone back and forth on the code, specifically regarding the random and repeated statements. In my latest edition, I am using proc mixed and the code is as follows: proc mixed; class row trt tree year; model yield = year trt trt*year/ddfm=kr2; random intercept/subject=row; random intercept/subject=row*trt; random intercept/subject=row*trt*tree; repeated year/subject=row*trt*tree type=ar(1); lsmeans trt/adjust=tukey; run; My main question is, what subjects should I include in my random and repeated statements? I believe I should account for differences within blocks and experimental units, but do I also need to include variance within observational units (row*trt*tree)? I have also attached the dataset and sas code. I would appreciate any insight. Thank you! Eliott
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