So last week I got to be a teacher for a class. The Agriculture, Food and Natural Resources class from nearby Fowler High School came by for a lesson. From me no less. There were around fifteen students who showed up at 7:40 to listen and learn. And that's a.m. by the way. So I filled their heads with a lesson on soils, soil chemistry and nutrients, growing crops and careers in agriculture. Now there's a class worth taking. In fact if I wasn't the teacher I would have enrolled just to hear it. But it was fun for me and I know the students learned a thing or two.
Well during the class I talked about the importance of a soil test as a guide for farmers to know what fertilizers to apply to the crop they are growing. I mentioned that how a soil sample is collected can influence the results. Now I have often talked about how you should use a clean plastic bucket to put the samples in, and not to use a metal pail as this could influence results. But like a lot of know-it-all talkers, I had never actually done a comparison. So I made the students do it for me. Isn't that what teachers do?
So we went outside to a field behind the parking lot. I'm not sure who is farming there, but sadly they don't use AgroLiquid fertilizers. Anyway, we had three sampling comparisons. First was the use of a stainless steel probe and a plastic bucket, which is the recommended procedure. Second was the use of a stainless steel probe and a galvanized bucket. And third was the use of a shovel and hand scoop. Many people use this when they don't have a probe. But you stick the shovel in the ground, pull it forward leaving a space in the soil, and make an upward scoop with your hand from a depth of around eight inches. Then put the soil in a plastic bucket. So we took ten samples around the field, with each method collected right next to each other. I sent the results to Midwest Labs, and just got them back. Selected results are in the table.
The results were similar for pH, organic matter (%OM), cation exchange capacity (CEC) and P1 phosphorus. The phosphorus is really low here. (I would use Pro-Germinator for sure.). Potassium has a little variance, but is generally close and also very low. (Kalibrate would help.) But look at the Zinc readings. The level from the galvanized bucket is super high. After all, galvanization is a zinc coating of steel, and enough flaked off into the sample to alter results. So don't do that! The copper level was also higher, but not sure if that is from the metal pail. Maybe there was a penny in the ground or something. But lesson learned. Class dismissed. (And no one even gave me an apple. Do they still do that?)