Post
by andy10917 » March 21st, 2021, 10:39 am
Oh, this one presents some challenges whether you're the member trying to work this soil or the more-experienced person trying to interpret what the soil test results are telling you...
I always start with a cursory skim of the numbers to make sure that the numbers on the test results are consistent, and that they make some sense when taken as a group. But right from the start, this one had conflicting data. It's a very sandy soil (TEC = 3) with a poor organic matter component (OM < 2). I glanced at the cation numbers and they painted a picture of a soil that had enough Calcium, but was pretty deficient in Magnesium and Potassium. My guess was that since the cations push the pH higher and they were short, the pH was going to be around 6 or maybe even a bit lower. So I glanced at the pH number and it was 7.
WTH?
Something in the soil was driving the pH higher and it wasn't the typical components. Time to dig deeper into the numbers. I went to the Saturation numbers and there it was << red light now flashing >>. The Sodium component of the Saturation numbers was pretty much off the charts -- where we would expect a Sodium component to be 0.5% to maybe 1.5%, this was 6.1%. Not good - not good at all. And since you're in Ronkonkoma, it ain't coming from being very close to salt water. It could be from road salt that the town was applying over the winter or ice melter that you were applying, but even then if you did many samples from all over the yard it shouldn't be that high. Did you do a lot of your samples from near areas like driveways or the street?
So, it's not the pH that's the challenge, it's the fact that the pH is where it is due to lots of Sodium, and that needs to be addressed.
Let's dig into the rest of the story now...
Overall, the soil is very sandy and won't hold nutrients well. This is likely from a combo of a natural sandy soil in your area, pulling up trees that "flipped" the topsoil and subsoil, and the use of subsoil Fill instead of Topsoil to level the yard. What's done i done, but it will take many years of applications of mulched leaves, compost and/or peat moss to raise the OM% significantly to improve the soil's nutrient holding ability. If you wish to, this can be accelerated somewhat by the application of Humates to the soil, and we can discuss that farther if you care to.
In the cations, you are very short on Magnesium and Potassium. You actually have more Sodium (bad) than Potassium. The challenge is that the way to remove/displace Sodium is with the use of Gypsum, which applies Calcium that you already have enough of in your soil. Again, it is what it is.
Get "Fast-Acting Gypsum" and apply it at the heavy-bag rate as soon as possible, and again in about 8 weeks. Also apply a "balanced fertilizer" like 10-10-10 or 19-19-19. Pick a balanced fertilizer that you can get and post the NPK for rates and frequency. It is likely that you'll need to apply it every month or six weeks. This will also begin to fix the Phosphorus deficiency that you have,
Sorry to say that I do not know how much success you'll have trying to establish a lawn until you have the Sodium problem and the other nutrients moving in the right direction.
If you wish to discuss building some nutrient-holding capability through the use of Humates, reply and we can discuss.
I'm sure you're going to have lots of questions, and I'm willing to work with you to do this on an ongoing basis. Let's take this a step at a time.
