# Micros



## Vol (Jul 5, 2009)

From DTN/Progressive Farmer.

Regards, Mike

https://www.dtnpf.com/agriculture/web/ag/news/article/2016/04/29/tissue-test-determine-value


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## hay wilson in TX (Jan 28, 2009)

I am probably very old fashion, but I was told many years ago not to bother looking for micro nutrients with a soil analysis. Way too small amount to be able to find anything at all in a standard soil sample.
Use a plant analysis for a reasonable Micro nutrient reading.

For some reason I was looking at Cobalt for alfalfa. Even using a plant analysis I needed a more than double sample size, just so the lab can find something at all in the entire sample. Until I took the hint I was getting None Found reported with a standard sized plant sample.

I like the idea of looking for the Macro Nutrients in samples that are in depth stages.

Some times the soil analysis can be misleading. With soils that have excessive calcium we can have deficiency symptoms even with good soil analysis. I can have potassium deficiency symptoms even with a soil test in the *350 ppm* range. My really excessive calcium levels can block the uptake of a Very High Potassium soil level.

An *8,500 ppm Ca soil, plus a 4 - 6% Free Lime soil analysis* will do that to you.

I am pleased I eventually changed to Midwest Lab and received an education to go with the soil analysis. Something good old SWTSTC neglected in my education.

I also see Iron Chlorosis with ample levels of iron in the soil.

I fully expect to continue my education, well past my mid eighties.


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## vhaby (Dec 30, 2009)

hay wilson in TX said:


> I am probably very old fashion, but I was told many years ago not to bother looking for micro nutrients with a soil analysis. Way too small amount to be able to find anything at all in a standard soil sample.
> Use a plant analysis for a* reasonable* Micro nutrient reading.
> 
> Some times the soil analysis can be misleading. With soils that have excessive calcium we can have deficiency symptoms even with good soil analysis. I can have potassium deficiency symptoms even with a soil test in the *350 ppm* range. My really excessive calcium levels can block the uptake of a Very High Potassium soil level. An *8,500 ppm Ca soil, plus a 4 - 6% Free Lime soil analysis* will do that to you.
> ...


Bill, I like your careful choice of words and agree with you that plant analysis is a better way to try to determine plant needs for micronutrients. Because our bureaucracy has determined that we don't need to adequately fund soil fertility research to improve food production, there is very little research that has been done, or is being done on calibrating soil and plant analytical tests to accurately predict crop yield improvements from plant micronutrient (or even macronutrient) applications. As a result, most micro-nutrient recommendations based on soil tests are little more than SWAGS. We do need to push our legislators, both state and federal, to adequately fund soil fertility research.

Relative to your soil test reports that show that your soil contains ~8,500 ppm calcium, remember that this calcium likely is not all available for plant uptake in soil solution or on the soil cation exchange complex. The chemical extractant used, whether it be the old ammonium acetate extractant, the Olsen extractant, or the now widely-used Mehlich III extractant, solubilizes some of the calcium carbonate that you refer to as free lime.

I applaud you for your post-college self-education in soil fertility and plant nutrition that you have undertaken by extensive reading and attendance at educational events across the country.


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