My soil smells

[JesseFrank]

The soil of my lawn isn't the best, I know that, but I have to live with it.

In fact it consists of that yellow compacting sand, on top of that a few cm clay and then a few cm of "better" soil.My lawn of Malay grass looks pretty good though.It gets irrigated twice a day .

Today I had to dig a hole to plant a small tree, and when I digged through the clay which was all wet, I detected it had a foul smell.

I would like to hear your opinions on this.

[scunner]

What was the smell? Rotten eggs? OR some other noxious wiff?

Also, was the clay water logged?

It could just be the clay layer is waterlogged and there are some anaerobic bacteria doing their thing re decomposing organic matter, so you need to let it dry out a bit or provide some mean for the water to drain away or reduce irrigation time / amount.

Hope that this is of some use to you.

[pigeonjake]

ill agree, to much water,,,

[JesseFrank]

Yes the clay smelled like rotten eggs. I had a few weeks earlier a Thai worker around and when sitting squat she said I use too much "pooh" on the lawn, while in fact I never use any.

I assume that was the same smell she was referring to.

I'm also from the impression that in that area of the lawn the grass is stressed, e.g it gets red color, which I read on the web can be a sign of too much water.

Do you suggest I water less ?

[samuijimmy]

Yes the clay smelled like rotten eggs. I had a few weeks earlier a Thai worker around and when sitting squat she said I use too much "pooh" on the lawn, while in fact I never use any.

I assume that was the same smell she was referring to.

I'm also from the impression that in that area of the lawn the grass is stressed, e.g it gets red color, which I read on the web can be a sign of too much water.

Do you suggest I water less ?

Yes! Lawn should be fairly drought tolerant, as long as it is established....

Once a day watering, or even less than that should be fine! .... let the soil dry out a bit between watering !

[JesseFrank]

What was the smell? Rotten eggs? OR some other noxious wiff?

Also, was the clay water logged?

It could just be the clay layer is waterlogged and there are some anaerobic bacteria doing their thing re decomposing organic matter, so you need to let it dry out a bit or provide some mean for the water to drain away or reduce irrigation time / amount.

Hope that this is of some use to you.

I need to retract my statement regarding the smell, as I had to reopen the hole this afternoon.

It really smells like excrement instaed of rotten eggs, which is hard to understand since I have never added any to the soil.

[David48]

How close is the septic or holding/dispersal tank or the associated pipe network?

[JesseFrank]

How close is the septic or holding/dispersal tank or the associated pipe network?

My septic tanks are the proper black ones, and are at least 30 meter from that spot.

[Cylon]

Maybe run off from neighbor's septic ?

[JesseFrank]

Don't have neighbors.

Common guys, what does it mean if your soil smells like there is a lot of excrement inside, while there has never been added any.

Can too much water cause this kind of smell ?

[scunner]

yes it can, stagnant soil can really kick up a stench, especially if there's plenty of organic matter in it;

Soils with lots of clay can absorb huge amounts of water, which can lead to anaerobic conditions. Clay particles are extremely small and cannot even be seen with the naked eye. Because of their tiny size, clay particles can trap water between themselves that smelly bacteria can grow in. Clay soils do not usually stink until they have standing water on them or they are dug into. Digging releases the gasses that have been building up in the ground from bacteria.

So given all the available data I suggest your clay is water logged and that you need to reduce the amount of water going onto your lawn. The reason for the clay layer was to provide a barrier to reduce the rate of seepage from the thin top soil into the freely draining sandy subsoil,so just ease up on the watering and see how the grass does - also try to water at dusk as well, so that the water isn't lost to evaporation so easily.

[JesseFrank]

yes it can, stagnant soil can really kick up a stench, especially if there's plenty of organic matter in it;

Soils with lots of clay can absorb huge amounts of water, which can lead to anaerobic conditions. Clay particles are extremely small and cannot even be seen with the naked eye. Because of their tiny size, clay particles can trap water between themselves that smelly bacteria can grow in. Clay soils do not usually stink until they have standing water on them or they are dug into. Digging releases the gasses that have been building up in the ground from bacteria.

So given all the available data I suggest your clay is water logged and that you need to reduce the amount of water going onto your lawn. The reason for the clay layer was to provide a barrier to reduce the rate of seepage from the thin top soil into the freely draining sandy subsoil,so just ease up on the watering and see how the grass does - also try to water at dusk as well, so that the water isn't lost to evaporation so easily.

Well the clay wasn't added on purpose, it was rather a delivery of what was supposed to be top soil. It was only the day after the delivery that it was detected because it all stick to our shoes, and the majority has been scraped of again. After all it may actually haven't been a bad thing, as I probably can reduce the watering in that zone.

I always water at 5AM and 4.30PM.Will try out to lower the time in that particular zone. Thanks for the advice.

[cooked]

An established lawn doesn't need water twice a day. Try giving a lot every two - three days. If the lawn doesn't like this then you have far from ideal conditions for a lawn.

I graze the cows on my bit of 'lawn'.

When you dig down, how deep do the roots of the grass go? Are they down to the clay layer? If they are then the grass shouldn't show signs of thirst. Compacting sand: I guess you mean calcareous sand, that can set as solid as concrete. It is also calcareous, and lawns prefer acidic, river sand. I guess you have a lawn that tends to the yellow side, and that you have to use a lot of fertiliser.

I have limited experience with lawns here, but I have solved stuff like this by scattering 3 cm of river sand on the surface and raking it over.

I have rarely seen a lawn in Thailand that is worth looking at all the year round in Thailand.

[JesseFrank]

The grass I have is malay grass, which is known to grow horizontal. The roots are less than 1 inch below surface with that kind of grass.

The lawn looks nice green, hence that I get so many compliments from visitors, but in that particular zone it tends to turn dark red from the bottom up.In the other zones where there is less clay in the ground this symptom is much less visible.It looks like the ground in that zone is depleted faster from it's nutrients than in the other zones.

I should add that that zone has a bigger slope than the other areas.

The compacting sand is indeed the version you mention, it compacts very well, but still allows water to drain pretty well.

I added building sand last year and it improved the lawn very much.The problem is that I can't add much more because the lawn will be higher than my walk ways.However I have occasionally still some brown spots where the grass grows thin, and always in the same location.

Does that mean that I have to add sand at that spot or remove ?

I fertilize every 4 - 6 weeks and throw about 1kg/100sqm

[kickstart]

To much water,sand land can compact as much as clay land ,as Cooked said it dos not not need watering twice a day ,this is a tropical country,and the local grasses are very drought tolerant, as SJ said.

My cow paddock's have had no more 4 lots of rain this year ,and they are still green.and it has been hot.

You could try spikeing the lawn, a muck fork would do the job,help with the dranage a lot.

Get some wormes back will help to.

[JesseFrank]

To much water,sand land can compact as much as clay land ,as Cooked said it dos not not need watering twice a day ,this is a tropical country,and the local grasses are very drought tolerant, as SJ said.

My cow paddock's have had no more 4 lots of rain this year ,and they are still green.and it has been hot.

You could try spikeing the lawn, a muck fork would do the job,help with the dranage a lot.

Get some wormes back will help to.

I have worms in the lawn, since i find some daily on the paved walkways. Maybe suicide attempts

[NeverSure]

To much water,sand land can compact as much as clay land ,as Cooked said it dos not not need watering twice a day ,this is a tropical country,and the local grasses are very drought tolerant, as SJ said.

My cow paddock's have had no more 4 lots of rain this year ,and they are still green.and it has been hot.

You could try spikeing the lawn, a muck fork would do the job,help with the dranage a lot.

Get some wormes back will help to.

I have worms in the lawn, since i find some daily on the paved walkways. Maybe suicide attempts

When worms come to the surface it's usually because they can't get oxygen in the soil. It's probably waterlogged.

It's too bad that just before you planted you didn't thoroughly rototill the combination of topsoil, clay, and some yellow sand to assure drainage. Clay has a lot of nutrients in it (and will as others have said support anaerobic growth) but it needs drainage.

If that was my lawn I would kill it with Roundup. I would wait about 6 weeks until even the roots had decomposed into compost. I'd keep watering it lightly so that the lawn and roots would compost.

Then I'd have three layers to incorporate with a tiller. I'd have the existing lawn and roots as compost, the topsoil, and the clay. When I tilled I'd make sure I went all the way through the clay to the original sand so I'd be assured of drainage. The clay would break up and be mixed with the compost, topsoil and sand and would never again cause a drainage problem.

The dead lawn and roots become free compost. You can then rake it smooth, roll it, and re-plant it. The Roundup will have dissipated within a week or so.

In all types of growing, a lack of soil preparation will defeat you.

Good luck.

[IsaanAussie]

Neversure, you are a kindred spirit.

If you read the OP there was only a few inches of sand, clay and soil. Hardly a breathing soil base that the roots can permeate. Turf layers often just flatten the existing site with a scrapping of sand and lay the sod on top. If the site is normal hardpan, what do they expect to happen?

Sorry not a no till application for me, I agree with NS, get the rotary onto it with some quality compost incorporated before you lay turf or sow the grass seed.

If you were to rotary hoe the grass now, you can spray an EM solution to promote the composting rather than use roundup. The advantage is you do not kill off the biology. In fact add some nitrogen fixing bacteria etc. to get the soil life working for you.

[NeverSure]

IsaanAussie, I'm not familiar with that type of grass. Any lawn I've ever had would be very difficult to rototill right into the live sod. In a farm field we could simply turn it under with a plow, but in a lawn with my rototiller it would just mostly bounce.

That is why I would kill the lawn, keep it moist and let it rot including the roots. You'll know it has rotted when the grass can be easily raked away from the roots as a test.

If this type of grass has less density overall and you could till it as is, you have a good idea.

[samuijimmy]

In heavy clay areas we used to add gypsum in my days of lawn making and landscaping .... to help break down the clay.... not sure if it is available here, I have never looked....

I like Neversure's answer ^ except the Round Up part....which is not suppose to have a residual effect in soil.... give at least 10 days before disturbing roots I think would be better, but agree with the rest of what he suggests ....

Sounds like OP is in a farming area, perhaps can get a local with a tiller on a tractor to do tilling... if there is room of course....and wants to go through the process again!! Hand held tillers can be a very bumpy ride!!!

I have seen a few good lawns here, in Thailand, one just up the road from me is just about perfect year round .... but obviously prepped properly and it is given a lot of care and maintenance (local Thai Landscaper) .. will post a picture later!

[IsaanAussie]

You can get all three types of lime. Ag lime, gypsum and dolomite at most farm suppliers. Where I am gypsum is usually the hardest to get.

[cooked]

I think we discussed this before in another context, Isaan Aussie. If you already have a lawn that is over 'calcareous' you don't want to be adding more stuff like gypsum. River sand works miracles.

I agree with Never Sure that the best solution would be to zap the lawn, but then add river sand and get a tractor tiller to work it in, followed by a rotovator.

I originally suggested adding 3 - 4 cm of river sand because this would certainly give some results without too much disturbance.

I never had a failure when I was renovating lawns but I did sometimes sweat a lot before making a decision, often going for a more expensive solution when I knew that customers wanted results. Difficult to say without visiting on site.

[JesseFrank]

This is a picture of the lawn area I'm talking about, taken this morning. Does it look that bad ? Let me add that on picture it looks worse than in reality. Seems the camera brings out the brown spots more than the human eye.

[NeverSure]

The problem with gypsum and other limes is that they are highly alkaline. 5 pounds per 100 sq feet (or about 2.5 kilos for a square 3 meters on a side) will raise the PH about 1 point. It is very heavy and that much won't even completely look opaque on the area.

Because his lawn looks so green, I doubt his soil is acid enough to take much lime. Organic material will do as well and the long term solution is to get that clay broken up into topsoil and some of the sand underneath. The main reason I would use Roundup is to make the grass easy to till.

[NeverSure]

I think we discussed this before in another context, Isaan Aussie. If you already have a lawn that is over 'calcareous' you don't want to be adding more stuff like gypsum. River sand works miracles.

I agree with Never Sure that the best solution would be to zap the lawn, but then add river sand and get a tractor tiller to work it in, followed by a rotovator.

I originally suggested adding 3 - 4 cm of river sand because this would certainly give some results without too much disturbance.

I never had a failure when I was renovating lawns but I did sometimes sweat a lot before making a decision, often going for a more expensive solution when I knew that customers wanted results. Difficult to say without visiting on site.

The problem with gypsum and other limes is that they are highly alkaline. 5 pounds per 100 sq feet (or about 2.5 kilos for a square 3 meters on a side) will raise the PH about 1 point. It is very heavy and that much won't even completely look opaque on the area.

Because his lawn looks so green, I doubt his soil is acid enough to take much lime. Organic material will do as well and the long term solution is to get that clay broken up into topsoil and some of the sand underneath. The main reason I would use Roundup is to make the grass easy to till.

Oops, sorry Cooked. I didn't see your post.

[NeverSure]

This is a picture of the lawn area I'm talking about, taken this morning. Does it look that bad ? Let me add that on picture it looks worse than in reality. Seems the camera brings out the brown spots more than the human eye.

20140516_090752.jpg

Up to you, as they say. Knowing what's underneath would put me into high gear to fix it for the health of the soil.

[samuijimmy]

This is a picture of the lawn area I'm talking about, taken this morning. Does it look that bad ? Let me add that on picture it looks worse than in reality. Seems the camera brings out the brown spots more than the human eye.

20140516_090752.jpg

Looks very good.... there must have been some good prep work to get it looking like that..... too bad about the smell problem....

But I think seriously cutting down watering.... and see if the smell problem still exists might be the first step .... to try and see what happens...

I only suggested Gypsum as it was some we used (but had generally low PH where I worked ) .... but as with anywhere soil PH will vary .... factor to consider .... as with any garden project....

I suppose a good aerating machine might be good and then add sand as Cooked suggests... ( But has any one every seen in Thailand...? I would image golf courses must use? ) That might minimize the level getting too high...

This is the lawn just down the road from me.... it should be due for it's weekly trim tomorrow... It's a variety of Zoa grass that only he uses on his landscapes... I forget now which variety.... he was not around to ask... (although probably not available everywhere) ....( just for info rather than OP changing grass.... )

[kickstart]

Got to agree, use round up and get a tractor in ,but not a rotovator, they use to be popular some years ago in the UK, easy way of working the land,but farmers where finding that they where making a "smear" under ground, that water could not penetrate, and made a pan,this is the last thing this land/ lawn needs.

If the op desids to get rid of the lawn,looking at that photo the grass is green ,but dos not look over healthy,find a tractor with a set of sub soil tines go down 2 foot, and rip the lot up will help the land to breath,then plough, not easy with those palms in the way,this might sound daft,put a catch crop of sweet corn in ,this will give the land a change of crops,and will help soil structure ,you could eat the corn, you will get a crop in 85 days,then put it back down to grass.

My 2 stang worth.

[JesseFrank]

Thanks all for your suggestions, but I've really no intention of digging up my lawn, I was looking for a more simple solution to my problem.

I have the palm trees and the underground irrigation system, so getting in a tractor is asking for problems, let alone that we're talking of a lot of money to have it redone. If there really isn't any easy solution, than it will stay as it is.

[samuijimmy]

Thanks all for your suggestions, but I've really no intention of digging up my lawn, I was looking for a more simple solution to my problem.

I have the palm trees and the underground irrigation system, so getting in a tractor is asking for problems, let alone that we're talking of a lot of money to have it redone. If there really isn't any easy solution, than it will stay as it is.

Agree, after seeing the picture.... gives a whole different perspective of it..... shut off the water for a while! .... that's easy, and see if it helps !

Good luck with it ....