I was reading the latest issue of No-Till Farmer and the Technical No-Till Tip of the Month was about Avoiding the "Acid Roof" Pitfall, (written by Penn State University). I for one have never heard of this idea before or the concept of soil sampling a 2 inch deep layer strictly for the purpose of seeing what the pH is right on the surface. It went on to say that even if the normal depth sample doesn't recommend lime and if the field hasn't been limed recently that you should still test the top 2 inches and if the pH of the soil sample from the top two inches was below 6.2 you should apply 1 ton of lime.
So, does anyone do this type of testing, and if you do have you seen there be a large difference between the normal sampling depth and the top two inches?
What sampling depth does everyone pull for continuos no-till ground, and what grid pattern size or management zones do you practice and how often does everyone sample in a continuos no-till system?
I look forward to the comments because this "tip" is something I had never heard anything about.
Edit - We pull 4" cores on all of our continuos no-till ground.