Two short articles on simplifying fertilization and soil test interpretation

These articles put soil testing in context and explain an easy way to think about turf nutrition.

In 2008, I wrote this article for the Hawaii GCSA: “Use the nutrients already in the soil: simple fertilization”. Here’s an excerpt:

If we look specifically at fertilization, I have a simple approach, yet it seems that many golf course superintendents doubt that my approach to fertilization can work at their facility. At most courses, I think this approach will work better than you might expect. Of the 14 essential mineral elements, nitrogen, phosphorus, and potassium are usually found in the highest concentrations in turfgrass leaves. We can test the soil to determine how much of each element is present in the soil and available for plant uptake. In most soils, even in sand rootzones such as USGA putting greens, there are adequate supplies of micronutrients and of elements such as calcium, magnesium, and phosphorus. This can all be confirmed by a soil test. Once there are adequate levels of a nutrient in the soil, adding more as fertilizer will have no affect on turfgrass performance.

The argument about what is adequate or not is one that we could have a day-long discussion about. Some fertilizer companies or soil testing services will set the target levels for nutrients in the soil to be much higher than what is required for good turfgrass growth. The base cation saturation theory is particularly notable for trying to “balance” elements in the soil, so even if there are adequate amounts of calcium and magnesium and potassium in the soil, there can still be recommendations to apply more of an element to try to “balance” the soil. This sounds good, but it costs money to purchase and apply unnecessary products.

_I will list here, for golf course turfgrass conditions, what I consider to be minimum levels of adequacy for some of the essential elements

You can download the article to read what those levels are. Pretty close to MLSN, but a little higher. I wrote that before we developed MLSN. Now, I’d recommend using the MLSN guidelines.

The second article is by Bill Kreuser, with a title “Simplifying Soil Test Interpretations for Turfgrass Professionals.” I can’t find it online anymore. But the gist of it was the same as my “simple fertilization” article. Here’s an excerpt from Bill’s article:

While soil tests can be useful, their results are frequently over-analyzed and over-interpreted. Sometimes soil test results can be more confusing than helpful. It doesn’t have to be so difficult. The goal of this publication is to explain which soil test values are important and which values can be ignored.