I think the grid vs soil type discussion has been going on for 35 yrs around here. We did our 1st grids in '74, I think, maybe '73. But, the folks that say only sample by soil type have been arguing for about that long also. Still, I have never understood, if I'm sampling on 2, 2.5, or 3A grids, am I not hitting every supposedly mapped soil type in the field? If grids are approx 300x300', are you not going to hit every soil type out there? I just checked the U of IL Agronomy Handbook & they still suggest sampling on precise, repeatable points on every 2.5A (=grids).

The mapped soil types have come under scrutinizing discussions around here in recent years. We don't have digital soil type maps yet in our county. So, why not grid test & then you are sure that you're hitting every soil type change? Why take a chance on just looking at a fabricated soil-type map?

I think this is like deciding whether to be Methodist or Lutheran.