Can anyone suggest me reading about PROC NLMIXED for crop growth analysis. I do have some expertise to handle PROC MIXED but never used NLMIXED. It would be good to look at few examples on crop growth analysis testing different functions. If there would be any specific example for split-split-plot design of RCBD it would be awesome.
You should get a copy of the excellent textbook by Oliver Schabenberger and Francis Pierce (Contemporary Statistical Models for the Plant and Soil Sciences).
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.