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| So it's obvious you don't trust the lab(s) you use. What labs do you use?? Why use them if you don't trust them??
I agree that - only use labs that participate in NPTP and are willing to share the data; and weighing is much better than "scooping"
So how exactly do you analyze the data from all of these check samples you send in to see how proficient the lab is? When they don't meet your standards what do you do? (whatever your standards are; universities say +/- 10% accuracy is all the better that can be expected) Re-sample/re-analyze everything? Who pays for redoing everything? You? or your clients?
Why not find a reputable lab instead of doing the QA/QC yourself? Even if a few samples now and then are say +15% rather than within that +/-10% range, how much does it really affect things? IMHO, not very much. Remember, pH and fertility levels are constantly moving targets, and optimum levels are defined by a range, not a specific number! Yes, it is a science, but it's not a perfectly exact science. | |
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grid sampling ? again
