Tissue testing: sometimes my own words come back to haunt me

Yesterday I wrote of tissue testing (or more specifically, leaf nutrient analysis) that “I don’t like making nutrient application decisions” based on it and “I would not do routine tissue testing if I were a golf course superintendent.”

I’ve got more to explain about why that is. But I need to get this out of the way first. When I was a graduate student, I wrote an article that said tissue testing could be the final answer!

This is the quote that I’d like to have back, from an article in the May 2004 TurfNet Monthly entitled Q&A: water-based extraction methods for turf soils:

In general, I find it much more useful to look at soil test data as an indicator of available nutrients but to use tissue analysis as a means to detect nutrient deficiencies … Tissue tests tell us what the plant has, so there are no questions about whether a certain nutrient is available or not, deficient or not, or sufficiently mobile or not. In the tissue there are either adequate amounts or there are not. Final answer.

I’ve already explained at length many of the things I disagree with from that article. For tissue testing specifically, a big problem is knowing what are adequate amounts. When I wrote that article in 2004, I was convinced that soil testing interpretation was broken, and the leaf nutrient guidelines – which will classify almost every turf sample as adequate, by the way – seemed at the time a better alternative. “Instead of all this fertilizer being recommended based on problems with soil test interpretation,” I thought, “one can just do a tissue test, find that all is fine, and skip the unnecessary fertilizer.”

Now I wouldn’t even go that far. I think tissue tests are likely to cause confusion, and for turf management, I’d rather focus on producing a surface, instead of trying to adjust leaf nutrient levels.