Schreibdave's 2019 Soil Test

[schreibdave]

Here's my story:

- New construction in 2017.
- About 13K sq ft of lawn
- Full sun except for shade created by the house - It's a ranch
- I have PR growing now but my plan is to renovate in August - probably to a KBG mix
- No irrigation system but I have about a million miles of hose, a dozen sprinklers and 6 timers so I can irrigate if necessary
- My 2017 test showed me low on P and K so I have been mostly using 10-10-10 to get those numbers up. That product is easily available and economical.
- My primary interest right now is the P and K. I would do micro nutrients at some point in the future.

Since I am planning to renovate in August I could probably overdo applications now if necessary. Stress to the lawn is not that great of a concern if I can get the P and K better for my fall reno.

Unfortunately I followed Logan Labs directions on soil depth. I collected at about 6" which is deeper than I should have. If it matters, I know for sure that in 2017 when the final grade was done the top 10" of soil is all the same material. I was here when the excavator moved soil from the massive pile to my yard. So the soil at 3" and at 6" started out the same. However my P and K apps since 2017 may not have reached down to the lower depths.

Thanks

[andy10917]

With a heavy soil with a TEC of 15+, we need to balance raw numbers with the actual needs in the soil. A 15+ soil has a lot that it can hold.

In the cations, you're really heavy on the Calcium - it had me thinking about the possibility that the soil is calcareous. I don't think that's the case, but the possibility that someone (previous owner?) or provider of topsoil got heavy-handed with Lime is in play. The end-result is a pH of 8 which is pretty damned rare in NY. Not impossible to be natural, but it's at the edge of what's naturally present. You'll never apply Lime to that lawn's soil, but you're going to struggle to get Iron to be available without foliar FAS apps. You can't make the Calcium go away.

Potassium and Phosphorus are both short - but Phosphorus is much deeper a hole to climb out of. Now when both of them are short, we turn to balanced fertilizers. But the shorter season in the Syracuse area complicates that somewhat - we don't recommend Potassium in the Fall, and therefore we need to switch things around. Find a balanced fertilizer like 10-10-10, 19-19-19, etc and post the NPK for a monthly application until early September. Then you'll need to use a Starter fertilizer (high middle number) until about first frost - you'll need to pick one before it's time to use it and post the NPK.

The Iron number is good, but it's all unavailable at your pH. Milorganite might work at that pH, but if not the only other options are chelated Iron ($$$$) or foliar FAS every 3 weeks or so. Or live with color you can get.

[schreibdave]

the possibility that someone (previous owner?) or provider of topsoil got heavy-handed with Lime is in play. The end-result is a pH of 8 which is pretty damned rare in NY.

I am the first owner of a new home in a new development. The last time this land was used was as a farm. Not sure what they grew. Unless the farmer put lime down for some reason, I believe that the ph is as mother nature designed it. My last two houses (3 miles and 5 miles away respectively) had phs in the high 7s. Limestone Creek is about 2.5 miles from my house if that tells you anything.

Find a balanced fertilizer like 10-10-10, 19-19-19, etc and post the NPK for a monthly application until early September

True Value near me has had HJE 10-10-10 and it looks like 16-16-16 can be ordered. That's what I will likely use. If I go with 10-10-10 I will need about 130 lbs per app to do my 13K lawn. How many apps will I need to get my P and K where they need to be?

Here's a link to the label

https://www.hjefertilizer.com/-/media/f ... 0_35lb.pdf

Does my plan to renovate to a KBG blend in August need to be rethought?

Thanks!

[schreibdave]

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?

Thanks

[andy10917]

** Note: this may be an interesting read for those that want to understand soil test interpretation and planning **

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.

[schreibdave]

That was helpful. Thanks

I was planning to kill off my PR next month and reno to all KBG. Is there anything about my P and k deficiencies that would lead you to suggest that I hold off another year while working to get those numbers up?

[andy10917]

Nope. Just have Starter fertilizer prepped for when the Sprout-and-Pout is over.

[schreibdave]

Given last year's soil test, would Ironite be effective on my lawn?

[andy10917]

The simple answer in "No". Go back to last year's soil test thread and re-read the comments I made:

You'll never apply Lime to that lawn's soil, but you're going to struggle to get Iron to be available without foliar FAS apps. You can't make the Calcium go away.

The Iron number is good, but it's all unavailable at your pH. Milorganite might work at that pH, but if not the only other options are chelated Iron ($$$$) or foliar FAS every 3 weeks or so. Or live with color you can get.

You have plenty of Iron at 256 PPM - it's just unavailable at your Calcium levels, which are driving the pH to 8.0. Ironite will just add to the unavailable pile of Iron.

I'd encourage you to track the "Humates and Calcareous Soil" thread - we're experimenting to see if we can come up with a new way to address your issue. In the meantime, the only things that might work are listed above.