Soil Test Results - Recommendations on what to do?

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ChaseinTX
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Soil Test Results - Recommendations on what to do?

Post by ChaseinTX » Wed Dec 04, 2019 8:50 am

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I received the above test results, and am just curious what the experts think I should amend my soil with? I’m growing a hybrid Bermuda in West Texas, so the grass is currently dormant. I won’t do any soil amending until the spring.

From the results, it’s clear I need to add nitrogen, phosphates, sodium and iron. I believe I can buy nitrogen, phosphorus and iron pretty easily, but not sure on soil requirements for sodium.

I’ve got a loamy sand soil with very little organic matter. Is there anything to be taken away from the salinity test in the bottom right? It shows a neutral pH in bottom right, but alkaline at top of report, any reason to attempt to bring that down slightly?

Thanks for any help or insight you are able to give.
Last edited by ChaseinTX on Wed Dec 04, 2019 9:30 am, edited 1 time in total.

corneliani
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Re: Soil Test Results - Recommendations on what to do?

Post by corneliani » Wed Dec 04, 2019 10:57 am

Not an expert but I'll pick off some of the low-hanging fruit, to start. I should add that your report looks about as good as anyone can hope, esp with it being a sandy-loam type. There's nothing egregiously deficient that needs immediate "amending' in my opinion, but this report does give you a nice roadmap to follow over the next couple years.

Things that stand out on your report:
- Nitrogen is highly mobile and hence the low reading on the test. Frankly some labs don't even account for it at all. With your soil type I wouldn't be surprised if N moves through the profile within a month of application, so unless you just fertilized before grabbing the soil sample the labs won't pick much of it up. Ignore this result.
- I don't see any CEC numbers but your OM may be enough to understand they'll be on the low end of the spectrum. Consider regular applications of Humic Acid and/or Biochar to help with nutrient retention.
- the lower Iron levels aren't something that I would amend immediately, but instead it would give me the freedom to know that I can apply liberally throughout the year without worry.. and the added knowledge that the grass may respond well to this since it's a deficient mineral as it is. The 7-0-0 GreeneEffect product comes to mind.
- Sodium likewise isn't an issue. If anything it shows that the salinity levels aren't too high (ie toxic). Fertilizers are generally salty in nature so this gives you the freedom to apply fert as needed, including the likes of Ammonium Sulfate (which would also have the added benefit of lowering your pH over time).

Recommendations? This is a choose-your-own-adventure decision but the two options I would consider are:
- Starter fertilizer (such as CarbonX 8-24-4 / Lesco 18-24-12 / Scotts 24-25-4) for the first couple rounds to increase the P levels using a synthetic fert. Spray iron foliarly to get your pop of green. Switch over to CarbonX Pro if you want to continue adding biochar during your growing season. A big-box fertilizer (29-0-4?) with 6+% Iron can also work once you have applied your Phosphorous.

- Milorganite as a slow-release option that would also give you high K as well as Iron inputs. More expensive than first option but this may also help with adding OM into your soil (?). I would personally still add some biochar (Mirimichi CarbonizPN comes to mind) to help retention and add further OM.
Last edited by corneliani on Wed Dec 04, 2019 11:03 am, edited 2 times in total.

ChaseinTX
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Re: Soil Test Results - Recommendations on what to do?

Post by ChaseinTX » Wed Dec 04, 2019 2:34 pm

Appreciate the response! Good to hear everything appears to be in order. I thought the same, and was kind of surprised since I live out here in West Texas. Our water quality is poor, and usually high in salts. The lack of organic matter was no surprise to me.

The low nitrogen didn’t bother me, as I purposefully stopped fertilizing for about 2+ months Prior to sending the sample in. I currently use milorganite the majority of the time, as well as an occasional boost of iron with Ironite. Once this year I used a synthetic fertilizer, but every other application was milorganite.
Last edited by ChaseinTX on Wed Dec 04, 2019 2:36 pm, edited 1 time in total.

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g-man
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Re: Soil Test Results - Recommendations on what to do?

Post by g-man » Wed Dec 04, 2019 9:16 pm

@ChaseinTX Welcome to TFL.

This is a fairly typical Texas soil. Is this a TAMU lab results?

The main issue with the soil is the high pH of 8.1. You can have a great lawn with it, but it has some challenges. The main one is that iron is not really available to the plants via the soil. Adding iron via the soil will results in poor effect. You will be better off doing a foliar (via the leaf) application of iron. We call this FAS (Ferrous Ammonium Sulfate) and there is a whole thread on how to do it. Another option is to use Milorganite because the iron is plant available, but it is way more expensive.

Why is the pH high? Likely is limestone in the soil and it is reflected by the calcium value. It shows high, but I dont know what extraction method the lab used. It is likely that you have hardwater in your house. Can you lower it? Sometimes. It takes elemental sulfur at 5lb/ksqft in early spring and early fall for multiple years. Depending on how much calcium there is, it might not have a lasting effect. But like said, it is not the end of the world. Mine is also high, I just learn to live with it.

Phosphorus is on the low side. It is not deficient, but you can improve it. I recommend getting MAP (18-52-0) at a local farm fertilizer store (not at home depot) or maybe at a site one. Check in the Texas hometown folders for local places.

I dont see any other thing to address. In regards to the sodium, most plants dont like it. It seems that you have some. There is not much you can do about it other than flush it with water. Ideally rain water because the irrigation water might be high in sodium too.

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