Elevated Aluminum in Your Soil and its Effects

Okay, admittedly, sometimes we do not talk about the most glamorous topics in our Blog. Unless you are into soil chemistry, this may be one of those times.  But Aluminum and its effects on plant performance comes up regularly when reading soil tests, so here it goes…

If you are one of our ongoing, organic service customers, you know we require a soil report so we can see what is happening inside your soils. Many times the Aluminum reading far exceeds the recommended maximum for normal plant performance. Many wonder how the Aluminum got there and most want to know what it means when the reading is elevated. This article talks about where Aluminum comes from and when it affects plant growth and what to do about it… Soil Aluminum and Soil Test Interpretation.

A key point in the article is this: “The soil pH is probably the single most important management factor controlling the amount of Al+++ in the soil solution. Soluble Al is present in the soil when the pH begins to drop below pH 6.0. However, it is inconsequential in the vast majority of soils until the pH drops below pH 5.5. Even then, it is rarely a problem until the soil pH drops below pH 5.0. However, the amount of soluble Al increases dramatically in nearly all soils as the soil pH drops below pH 5.0.

As our customers know, adjusting pH is the first step in growing successful turf grasses. This article would hold that to be true for mitigating the effects of Aluminum on turf grasses. Our minimum threshold for pH in lawns is 5.8 with a target of 6.5 to 7.0. A pH below 5.8 negatively affects turf grasses and as we see from the article, also increases soluble Aluminum.

So, if you are freaking-out over elevated Aluminum in your soils know that the first thing to do is to bring your pH up and that will bring your Aluminum effects down. Adding Calcium (lime) will bring up your pH. Be sure to note that the maximum single application of Calcium is 40 lbs/1,000 square feet. If you need more than that you will have to apply every 6 months until you get the desired pH range for your plants. But eventually, you can make your grass happy by getting the pH where it likes it. 🙂

*** As a reminder, the lower the number the more “acidic” it is as can be seen in this graphic…

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