BAM8004 Soil Test Summer 2020

[bam8004]

Finally sent my soil sample in. Please see below for results (with Ammonium Acetate extraction of cations). Any suggestions will be greatly appreciated, though I would prefer the “best” vs “simple” approach. Will add link in Soil Test Interpretation Queue shortly…



LOCATION: North Texas (Plano)

GRASS TYPE: St Augustine – Appx 3,750 sq ft total (2,500 sq ft in front yard, 1,250 in backyard)

SUNLIGHT: Most of the yard gets mix of dappled sun/shade throughout the day and some direct sunlight. Turf has to compete with six mature trees for water, nutrients & sunlight.

SOIL TEXTURE: Haven’t done the jar test or anything yet, but it’s clay.

HISTORY: Moved in at beginning of September 2019. Switched sprinkler system to water ½” 2x per week in the morning vs 3x a week at night which is what it was set for when I moved in. Turned sprinkler system off for winter in early November, started it back up at the beginning of June (had been getting 1” of rain per week before then). Applied halts (pendimethalin) at bag rate at the beginning of October 2019 and again at bag rate in Mid-March 2020. Mulch mowed half the leaves in the fall, bagged the rest. Have been mowing at around 3”.

Took soil sample below on 5/5/20 (took forever to send it off), then dropped 32 lbs of Milorganite on 2,500 sq ft front yard on 5/9/20 (after taking soil sample - Milorganite bag broke when I was organizing the shed and didn’t want to be smelling Vitamin M in there for the whole summer), and then I applied 20lbs/1k sq feet of corn meal to the whole lawn on 6/27/20 to see if it helps with what I think are fungal issues. Have ordered SLS, yucca extract and kelp extract to make BLSC & BLKH, but haven’t applied it yet.

ISSUES/CONDITION: Front yard is ok, nothing spectacular, it has a few super deep green patches that pop out, and it seems to grow super slow even for St. Augustine. I think the slow growth is just due to the shade and the super green patches may be fungal, but they aren’t that noticeable. I’m pretty positive the back/side yard has some bigger fungal issues. STA in the sunniest spots of the back yard grow pretty vigorously, but still have the same deep green patches I see in the front yard. Bare patches have developed in an area between the patio and pecan tree and the patio. The side yard is mottled, with some parts growing vigorously with others barely holding on. If I can ever actually find a coffee can, I’ll do the chinch bug test, but I don’t think that’s what this is. These issues were present, but not as noticeable when I moved in last fall, they just seem to have gotten worse this season.

[andy10917]

Make sure to put a Link in the Soil Test Interpretation Queue pointing to your thread. Otherwise, it will get buried and forgotten.

[andy10917]

Hmmmm - that's a typical Plano-area soil, but it has a couple of very strange little twists - I don't see one like this very often...

The area is very prone to calcareous soils, and you have one. I can spot it and its tricks even through the AA test. You have a boatload of Calcium, and you're pretty lucky to get out of it with a pH of 7.8. But the surprise in the structural area is the OM% - wow! 10+%. You'll never need to supplement the organic matter. I'd love to know how that happened. Alas, there is nothing you can really do about the Calcium. Luckily, it's not a huge thing preventing you from having a nice lawn.

The "shortages" of Magnesium and Potassium are not real, and the raw numbers are adequate.

The Phosphorus is also OK.

The Iron is very low, but it's a moot point - it wouldn't be available at your pH. If you decide to try FAS for improved color (see the article for more detail, start off lightly on St Aug grass. You can always add a bit more the next time.

In the micro's, I see two strange items - the Zinc and Boron numbers are unusually high. Again, nothing to explain why.

So, everything is either high or adequate. What do you do?

Check your watering habits - make sure you're not watering daily or leaving it entirely to Mother Nature. Use proper mowing habits for St Aug. And while St Aug is not a fan of heavy fertilization, regular applications of 1 lb/K every 6-7 weeks are welcome. At pH's over 7.5, it can show chlorosis (yellowing) when not managed. Since you don't need Phosphorus or Potassium, you can use high-Nitrogen fertilizers.

I wish I could offer something, but a calcareous soil with your characteristics doesn't offer many opportunities that can be addressed off of a soil test.

[bam8004]

Thank you for the input! I was thrilled to see a Ph lower than 8 and organic matter that high. Wish I could take credit for the high OM, but I’ve been here less than a year. My best guess is that most of the OM is from 45 years of tree leaf litter, etc. Between the five mature oak trees and the big ‘ol pecan tree they drop what I guestimate is about 70 brown paper lawn bags packed full of leaves every fall, and what seems like thousands of acorns. Glad to hear I don’t have any major deficiencies, but I do have some follow-up questions.

FAS?
I assume FAS refers to the Ferrous Ammonium Sulfate on the spray iron applications article, correct? If that is the case would “starting off lightly” be something like 1oz of FAS per 1K sq feet mixed in 1 gal of water, or should I start off with an even more diluted solution. I also read in that article not to apply when temps are going to exceed 85 degrees in 24 hours to prevent burning. Our high temps are usually above 85 from May to Early October. Can applying at dusk or dawn and then watering the solution in prevent burning when applied at higher temps? I won’t be trying this in the 100+ degree dead heat of summer, but I’m wondering if watered in thoroughly if it can be applied temps are between 85-95 degrees. Also, I’m assuming the nitrogen in FAS’s Ammonium Sulfate (NH₄)₂SO₄ isn’t really significant enough to count towards the 1lb of nitrogen per 1k sq ft ever 6 weeks, or is my math wrong on that?
(NH₄)₂SO₄ is 21% nitrogen.
100/21=4.71lbs of (NH₄)₂SO₄ to equal 1lb of nitrogen
1oz of FAS contains only .85oz(.053lbs) of (NH₄)₂SO₄
.053/4.71=.011 lbs of nitrogen provided in 1oz of FAS

Best Lawn Soil Conditioner impact on Corn Meal as anti-fungal?
I applied 20lbs/1K sq feet of Corn Meal last weekend in hopes that it may have some impact on what I think are fungal issues. I know there’s a big debate as to whether or not this actually works and it will take at least 3 weeks to see any results. I was going to apply BLSC this week or next, but I’m wondering if I should hold off on that for at least two weeks to make sure it doesn’t somehow inhibit/effect the environment the corn meal is trying to work in. Any thoughts on this?

Thanks again!