Posted 10/13/2021 07:31 (#9266250 - in reply to #9265146) Subject: RE: Soil sampling size
I would go visit midwest labs.
Do you need to lime or is there manure history? If so I would lean to grid. If not I would lean to zone sampling.
It's not about putting dirt in a bag and filling to the line. You will get an "answer" from the lab, but how accurate will it be?
However you sample do it very consistently. Taking the cores is where the most errors occur. If you submit 0-6", make sure it actually is a 6" core, not a 6.5" or 5.5" core. Don't fondle the soil with your bare hands. Don't mix up the cores and only put some of it in the bag. Put the bags in the refrigerator until it goes to the lab.
Technically, anything larger than a 1/4 acre grid represents alot of guessing and often inaccuracies. Less than 12-16 cores per sample doesn't represent a location accurately either.
Good grids takes ALOT of time. Takes cores from wherever in grid best represents that grid, not just the center. Then a good software to more accurately create kriged maps.
The more details you hold yourself to the better results you will get. Striptill is great way to apply your vrt.