If you read it and want to discuss it (with questions), please use this thread and let's avoid hijacking his thread.
Here's a direct link to his question and my response: Dave's Soil Test Question. The soil test results being discussed are up higher in the thread.
Here's his question:
and here's my response:If I put 1 lb of P and K down monthly does anyone have an opinion as to how many apps I will need before those numbers get into the acceptable range? Is this a multi year effort?
This is going to be confusing for you, because the numbers on your test show amounts at the 6" test depth, and most of the time we do calculations at the 4" depth for grasses. The numbers we use are therefore (4/6th for the conversion), or 67% of our normal numbers for anything calculated in lbs/acre. Things calculated in PPM do not need conversion. Sorry, that's what happens when you have the tests listed at the 6" test depth, which you did.
Soil chemistry is far more complex than "if I need to get from 58 lbs/acre of Phosphorus to 170 lbs/acre, and I apply 1 lb/K monthly (43 lbs/acre), then it will take X number of months to reach my target".
You've got a boatload of Calcium in your soil. In a "perfect scenario", we'd want to see the Calcium around 68% base saturation. You're at almost 84%, and there is no way to remove Calcium. Now, Calcium/Magnesium/Potassium are all vying for exchange sites, and Calcium has an advantage in a head-to-head competition. This means that Potassium is going to struggle to bind to your soil and find a permanent home. If it doesn't, it can flush out ("leach") over time. It's sort of like pouring water into a glass with a hole drilled in the bottom - it is leaking out at some rate as you pour it in. What is that rate? We don't know, but can take educated guesses once we have a year-to-year trend.
So, if we lose Potassium to leaching, is this a hopeless cause? No - because we're adding it monthly, so there's always some present. Optimal? No, but it's better than not putting it down.
Now, the raw number for Potassium in your soil is actually not terrible - it's 144 lbs/acre (215 * 0.67). We'd like to see that at around 175 lbs/K. But (another complication) - the high TEC means that the raw numbers and the "desired numbers" are not in the same ballpark. Soils can act funny when ratios of one nutrient is not in balance (by ratios) to another. The short-term goal is to at least get the raw numbers working, and move slowly toward the balanced ratios in the "desired values" over time.
So, the Potassium situation in your soil is not horrible. But the Phosphorus numbers are. Converted to the 4" depth, you have about 39 lbs/K - far below the 170 lbs/K I'd like to see even for raw numbers. That will take a long time to correct, but at least Phosphorus doesn't vy for exchange sites.
I could go on and on, but I feel I'm just going to confuse you more. The bottom line is that you'll be applying Phosphorus and Potassium for quite a while, but we'll watch how things go with the lawn's quality as we get at least the raw numbers addressed.
I'm sorry that this is probably way more information than you were expecting, but I wanted to get you understanding that your question isn't straightforward. Ask more questions if you'd like to.
Now you've got a preliminary feel for what we (and Logan Labs) consider when we interpret your soil test and why we don't just publish stupid target numbers via a single calculation - it doesn't work well to do that.