I conducted a study for two years with two locations (fields) in the first year and two different locations (fields) in the second year for a total of 4 site-year combinations. At each location I have 4 blocks. Within each block is the whole plot of cover crop (3 factors) and a sublplot factor of N rate (3 factors). We took soil samples in each plot three times during the year. My objective is to determine how different cover crop and N rate treatments affect various soil measurements and if that varies by sample timing and/or the site and year combinations. Below is the code I have so far. I am not sure if it is correct or not. proc mixed data = CCSHCorn1 covtest plots = studentpanel ;
class block siteyear sampletiming covercrop nratecat ;
model activeC =siteyear|covercrop|nratecat|sampletiming /ddfm=kr2;
random block block(siteyear) covercrop*block(siteyear) ;
repeated sampletiming/subject=block(covercrop*nratecat)type=un;
lsmeans siteyear*covercrop*nratecat*sampletiming /diff adjust = Tukey;
ods output tests3=tests3
CovParms = RandomVar ;
ods exclude lsmeans;
ods exclude diffs;
ods output diffs=ppp lsmeans=mmm;
run;
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