# Fescue - drought burn



## jebmke (Apr 5, 2020)

I have tall fescue lawn in mid-Atlantic. The back was originally almost all weeds and wiregrass. Did a complete kill/re-seed three years ago (front was done 4 years ago). Due to drought and thinning, have had to over-seed the back each of the last two years.

This summer, again, drought is taking a toll. This is beyond just going dormant. Dead areas and burn strips from lawn mower (see photo).



Here also is the latest soil test that was done. The soil in this part of the state is heavy clay and this area is no exception.



The yard is not irrigated and I have no immediate desire to install an irrigation system; this is a fairly large yard and I'm not sure our well capacity is sufficient. We have it cut high and have no problem with the look of a dormant lawn when the weather gets hot and dry.

I have some ideas as to what is going on but I'd like to hear from others who can interpret the image and soil test results.

I don't think it has anything to do with treatments since this area is treated the same way as the front and the front has no issues.

Thanks for any input you might have.


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## stevehollx (Apr 8, 2020)

If you don't want to irrigate, I think you need to be subject to the fact that you will need to overseed every fall.

Maybe trying improving organic matter some more due to the lower CEC (maybe add humic, kelp, mulching when mowing) to improve drought tolerance a bit, but doubt it will be a panacea here.


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## g-man (Jun 15, 2017)

You say heavy clay, but your CEC is 4.4. i dont think that's likely in MD.

The weight of the mowing machine goes to the tires. Mowing drought stressed lawns will cause damage in the tire tracks.

Outside no irrigation, what else do you think is going on?


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## jebmke (Apr 5, 2020)

Almost all the soil in this section of the Eastern Shore is clay. The front receives the same amount of sun and rain as the back yet none of this type of burn stripping occurs in the front.

It seems to me that something about the soil in the back is preventing the grass from developing deep root systems and the equipment rolling on the back simply damages the grass plants whereas it doesn't in the front.

I am not familiar with the term CEC so I can't comment on how that fits with the soil types here.

One thought I have is that when the pool was installed in the back (by other owners) that soil pulled from the excavation may have been spread on the back such that it has different characteristics than the front.


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## g-man (Jun 15, 2017)

You should test your soils from the back in a different test than the front to see if there are soil issues. Subsoil from an excavation can lack nutrients and organic matter, thus making the grass struggle to survive.

CEC is a measurement of the ability of the soil to hold on to nutrients (cations). Sand particles are large so there are less cation sites vs clay are very small have have a high number. There are exceptions, but it most cases a CEC value less than 5 is likely a sandy soil. A CEC above 25 is more likely a clay soil. You also said shore, so I would expect a sandy loam in that area.


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## gllong0808 (Aug 13, 2020)

Hey jebmke,

I am on the Eastern shore as well. g-man's recommendation for different soil tests is spot on. Our property has areas of clay and sandy loam, so I do 3 different soil tests with Waypoint. Because of the different soil make up on my property, I get different treatment recommendations for lime, dolomitic in some areas and calcitic in others and fertilizer recommendations differ for me by area.

Good luck!


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## jebmke (Apr 5, 2020)

g-man said:


> You should test your soils from the back in a different test than the front to see if there are soil issues. Subsoil from an excavation can lack nutrients and organic matter, thus making the grass struggle to survive.
> 
> CEC is a measurement of the ability of the soil to hold on to nutrients (cations). Sand particles are large so there are less cation sites vs clay are very small have have a high number. There are exceptions, but it most cases a CEC value less than 5 is likely a sandy soil. A CEC above 25 is more likely a clay soil. You also said shore, so I would expect a sandy loam in that area.


This test is the back only.

"Shore" in this context is the Delmarva peninsula -- the "Eastern shore" is the eastern shore of the Chesapeake Bay. We are on the bay side of a major river -- soil west of the river is clay and east of the river is more sandy. Geologically, the soil on our side of the river is sediment from the Susquehanna River deposited over millennia. I suppose sand might have gotten mixed in by a contractor. But the surface of the back yard is like cement so if there is sand, it certainly isn't porous sand.


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## sheepfescue (Jul 29, 2019)

Hello,

It is possible that browning along tire tracks is Ascochyta Leaf Blight. One of the specific features of that is that it follows tire tracks.

https://hortnews.extension.iastate.edu/2010/6-23/ascochyta.html


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## corneliani (Apr 2, 2019)

+1 ^
I was going to mention Ascocytha as well, though I'm not sure if it's a treatable fungus or if it goes away with proper watering & cultural practices.


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## jebmke (Apr 5, 2020)

corneliani said:


> +1 ^
> I was going to mention Ascocytha as well, though I'm not sure if it's a treatable fungus or if it goes away with proper watering & cultural practices.


Thanks; I'll ask my turf service if the fungicides they use are effective against this. The lawn was treated in early June and again in early July. We tend to gt brown patch this time of year and so far, I haven't seen any of that. It has been extremely dry since early spring but when the nights get warm, it is usually humid weather and low air flow.


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## Virginiagal (Apr 24, 2017)

I wonder if the hardness of the soil might have something to do with the calcium to magnesium ratio. Magnesium is a much higher percentage of cations than normal. Magnesium tightens up soil. As for why the grass isn't doing better, maybe water is not being absorbed like it should. Maybe it tends to run off instead of making its way down into the soil?


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## Deadlawn (Sep 8, 2020)

It is also possible for a sandy loam to become compacted which may give you the impression it is clay. Using a heavy riding mower doesn't help that either.

A CEC of 4.4 is definitely not clay. Your soil has trouble holding water and nutrients.


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## jebmke (Apr 5, 2020)

Deadlawn said:


> It is also possible for a sandy loam to become compacted which may give you the impression it is clay. Using a heavy riding mower doesn't help that either.
> 
> A CEC of 4.4 is definitely not clay. Your soil has trouble holding water and nutrients.


Interesting; perhaps I should get another test done. I remember when this sample was taken. It had been a very rainy 6-8 weeks and the sample was taken in mid-September. The core he pulled up was at least six inches long (probably longer) and it was saturated with water and sure looked like clay to me. I remember remarking to him that we could probably risk seeding early since there was so much water in the ground compared to most years at that time.

I wonder if the reading from the test was incorrect?


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## Virginiagal (Apr 24, 2017)

Did you pull samples from several spots and mix them together? Or is the test just on the soil from one probe? The problem may be with the subsoil from the pool excavation. I'm paging @Ridgerunner as he may some ideas on flocculation and what you might do. It's an interesting test.


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## g-man (Jun 15, 2017)

Some clay soils can have low CEC. It depends on the type of clay. I think piedmont clays is one.

But just because the soil becomes hard when it is dry or water not flowing does not mean it is clay. If you test your soil again, you can ask for a soil structure test and they will determine the percent of clay, loam and sand in the soil.


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## jebmke (Apr 5, 2020)

Virginiagal said:


> Did you pull samples from several spots and mix them together? Or is the test just on the soil from one probe? The problem may be with the subsoil from the pool excavation. I'm paging @Ridgerunner as he may some ideas on flocculation and what you might do. It's an interesting test.


He pulled three samples from the area


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## Bigfeather1 (Jun 11, 2019)

You could also take a qt jar, fill it half full of soil from the back yard, finish filling it up with tap water, shake it up, let it settle. That will tell you how much clay you have. I live mid-way on "shore" . Some areas might have 2 feet of clay, move 100yds might have 4 inches. Soil scientists took samples before digging my wildlife ponds. You might want to test your front yard too so you could determine if your yard has same soil characteristics.


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## Jeff_MI84 (Sep 28, 2020)

I have to agree about testing soil elsewhere. My front and backyard renos have slightly different soil. Also @g-man is right about damage in the tire tracks on a heat/ drought stressed lawn. It almost looks like scorched grass where the tires were.


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## jebmke (Apr 5, 2020)

This is a soil test that was done in front a couple of years earlier than the back. 


Setting aside the irrigation question, my turf management guy suggested aeration and compost (Leafgro).

Landscape guy (not formally trained) also suggested aeration but first choice amendment is chicken manure. This is used a lot in the area on farms but I'm wary of it because we are on the waterfront (Chesapeake tributary).


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## Virginiagal (Apr 24, 2017)

In response to the older test, did you apply lime? To the whole yard or just the front? Calcitic or dolomitic? The CEC on the front is very low too. In general on a low CEC soil, it's good to use slow release amendments or to spoon feed. Instead of doing 1 lb of N once a month in the fall, you could do 1/2 lb twice a month. As for chicken manure, wait until the fall and make sure it's not fresh if you want to use it.. For that matter, wait until early fall for any kind of fertilizer. Organic matter is always useful. Leave your lawn clippings on the lawn and mulch mow your leaves into the lawn when they fall. Your roots growing and dying back supply organic matter too.


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## jebmke (Apr 5, 2020)

Virginiagal said:


> In response to the older test, did you apply lime? To the whole yard or just the front? Calcitic or dolomitic? The CEC on the front is very low too. In general on a low CEC soil, it's good to use slow release amendments or to spoon feed. Instead of doing 1 lb of N once a month in the fall, you could do 1/2 lb twice a month. As for chicken manure, wait until the fall and make sure it's not fresh if you want to use it.. For that matter, wait until early fall for any kind of fertilizer. Organic matter is always useful. Leave your lawn clippings on the lawn and mulch mow your leaves into the lawn when they fall. Your roots growing and dying back supply organic matter too.


Don't know on the lime - was done by turf co. We don't do anything here except fall and spring. N is heavily regulated (for turf cos but if done on your own outside regs and you get caught you get some heavy fines).

btw - what is role of gypsum in breaking up clay. I have sibling in VA whose lawn guy uses gypsum as amendment to break up red clay there.


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## Virginiagal (Apr 24, 2017)

But do you have clay? With such a low CEC, it is doubtful. There are soil structure tests to find out just what kind of soil you have, Gypsum may be useful in displacing magnesium, which is taking up a lot of cation space. But I don't know if you should address the magnesium. Gypsum might displace potassium and sodium too. With such a low CEC, you can't go around displacing too much stuff. Nutrients are barely hanging onto anyway. Here's an article on gypsum:
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/gypsum.pdf
Ask your turf management guy what he thinks.

I expect they did add lime in response to the other test. Your pH on the most recent test is fine now. No lime is needed now and you should avoid magnesium. If you were to use gypsum, it would add calcium but would not affect the pH.

The front yard soil has a low CEC too.


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## Deadlawn (Sep 8, 2020)

Gypsum has both calcium and sulfur, so is good to use if you need both of those nutrients but don't want to change your pH. The calcium and sulfur cancel each other out as far as pH.

Gypsum has been marketed as a way to loosen compacted soil, but there is no real evidence it does that.


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## jebmke (Apr 5, 2020)

Virginiagal said:


> But do you have clay? With such a low CEC, it is doubtful. There are soil structure tests to find out just what kind of soil you have, Gypsum may be useful in displacing magnesium, which is taking up a lot of cation space. But I don't know if you should address the magnesium. Gypsum might displace potassium and sodium too. With such a low CEC, you can't go around displacing too much stuff. Nutrients are barely hanging onto anyway. Here's an article on gypsum:
> https://s3.wp.wsu.edu/uploads/sites/403/2015/03/gypsum.pdf
> Ask your turf management guy what he thinks.
> 
> ...


Thanks. He did add lime but I just don't know whether it was dolomitic or calcitic.


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