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Little River, TX | The lab is going to dry the samples anyway and then grind the soil to a manageable mesh size.
If you have a clay soil that holds tightly cations when wet that soil will release these cations as the soil drys, be it in the ground, in a paper sack or in a forced air oven.
Because a lab will force dry, then grind, then thoroughly mix that sample, then pull a sub sample to test, their results will have a better than 90% confidence factor, for that sample.
The extreme differences in test results are due to differences in the soil. From one square foot pull enough probes to fill one of those little paper sacks, then move over 4 feet and do the same and the results will be dramatically different. Do this exercise a few more times if you desire and you will wonder if there is any validity in soil test results. This is why we pull a number of samples to make up the sample sent off to the Lab. The idea is to even out these differences.
I have considerable confidence in the results for pH & organic matter. I have no confidence in the reported results for nitrogen, sulfur or any of the micronutrients.
Now for the rest of the story. I depend more on tissue testing and records from previous seasons to develop my fertilizer program. | |
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Soil test in extremely dry soils?
