I am a beginner with the use of SAS and particularly Orthogonal contrast. My experiment involve the use of 4 rate of Nitrogen at 3 time of application plus a control for bread wheat. The trail was in the field by RCBD with three replication. The different responses are labeled as variables 1-39 as depicted in the SAS command I just prepared. I used Proc IML to get the coefficients for the polynomial effects of N-rate.

My treatments are:-

N-rates= 4

N application time =3

Control=1

Total treatments= 13

PROC GLM;

CLASS Treatment Level Replicate;

MODEL v1-v39= Replicate Treatment Level Treatment*Level;

/*Control vs all N-supplemented*/

CONTRAST 'CTRL Vs. All' Treatment +12 -1 -1 -1 -1 -1 -1-1 -1 -1 -1 -1 -1;

/*N-time main effect*/

CONTRAST 'Full Vs ½,1/3 ' Treatment 0 1 1 11 1 1 -1 -1 -1-1 -1 -1;

/*N-Level main effect*/

CONTRAST 'Level' TRMT 0 +1 +1 -1 -1 0 0 +1 +1 -1 -1 0 0 ,

TRMT 0 +1 -1 0 +1 -1 0;

/*Interaction effect*/

CONTRAST 'rate x time' TRMT 0 +1 +1 -1 -1 0 0 +1 +1 -1 -1 0 0 ;,

TRMT 0 +1 -1 0 +1 -1 0 ;

/*Orthogonal polynomials for trend comparison of Level effect (averaged over frequencies, control included)*/

LS Means Treatment /DIFF lines;

Run;

Are there other things to consider in my analysis???

Thanks for anticipated help.