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Rexburg, Idaho

Is this possible?
Last fall I had a soil test done. I took random samples (probably 15-20 areas) from the entire patch (15,000 sq feet) and I sent the results to reputable lab. The pH came in 8.1 slightly higher then the 7.9-8.0 that the readings had been over the previous 3 years. The results came back pretty much in line with what I had seen before except the OM dropped from 6% to 1%. The % lime was 1% down from 2% the year before. I added the equivalant of 50 bags of leaves, 13# of soil sulfer 1 yard of manure, and 5 bales of straw to every 1000 sq feet.
I did not do a soil test this spring. Last week I took a sample from 1 planting site (about 900sq feet). I did not do samples from the other planting sites in the patch. I took about 10 cores scattered throughout the planting site.
The results came back and I am perplexed. My pH is now 6.2 OM is 3%, % lime is 0%.
My question is--is this kind of drop even possible? Is this a lab error, sampling error or other.
I have split the patch into 1/2 before and sent samples from each half and have never had a significant difference between the two halves. Is it possible that this one planting site is that much different then rest of the patch. This same site did grow my biggest pumpkin ever 1071 although it was split.
Did I finally neutralize the free lime in the patch and drop the pH? It should take significantly more sulfur then 13# to do that.

7/24/2008 11:47:59 PM

Puyallup, WA

In the past, I believed that I received a "bum" report from an A&L Lab. If I were you, I'd send off another sample to another laboratory. For $31 or so, you could have peace of mind.

7/25/2008 12:31:39 AM

Columbus,ohio

Ya that sprobly a good idea...also you can go to the store and but ph tests or a ph reader

7/25/2008 2:13:25 AM

Ohio

Brian,I dont think the ph test kits are that accurate but there is a ph meter that Larry Checkon turned me onto (http://www.planetnatural.com/site/image.html?sku=ph-meter)
and it has always been real close to what my soil test from the lab have been in the past, you might want to try this?

http://bigpumpkins.com/MsgBoard/ViewThread.asp?b=3&p=239488

7/25/2008 2:44:51 AM

Pocatello ([email protected])

That's always been my excuse, as a thinker, to be skeptical at soil testing. Throw in my natural desire to be cheap, and I end up rarely getting a test done.

Lets say a month ago I threw out something granular... anything. Then lets say that this particular 3mm lump of something just didn't see the conditions to break down. Then this little lump gets into the sample, then the sub-sample, the actual thimble size volume of dirt that gets tested. That's going to throw that test way off.

Not saying that this has happened, but a zillion things can go wrong.

I once bought a soil test meter. It said my pH was around five or six. It quite simply aint that. It's likely between seven and eight.

I'm on a first-name basis down at a local nursery. I've even given a grower's seminar there. They sell home test kits... but since the people know me, they say, "Ah, this stuff really doesn't work..." ;-)

So anyway, I'm not saying that all lab tests are bad, but one out of ten is probably bad. They should be taken with a grain of salt... (pun intended).

7/25/2008 10:47:30 AM

Rexburg, Idaho

I am not worried about the quality of the lab these guys are good.
I suspect one of three things 1) sampling error 2) that there is significant variability in areas of the patch that I have not realized previously because I sampled larger areas and mixed them together 3) I neutralzied my free lime. I'm not sure which it is. I will sending in new samples this week.

7/26/2008 10:28:11 AM

Windsor, Ontario, Canada

Cliff you have a point about the amendment throwing the sample off in theory, but that is why you should take a dozen small samples, let dry, mix all together, sample from that and send it away.

7/26/2008 1:37:07 PM