Weed Mats

[sibeymai]

Does anyone have experience with weed mats to prevent the growth of weeds around trees ?

Usually these are around 1 metre square plastic. They block sunlight preventing weed growth but allow water and nutrients to pass through to the soil.

Are there suppliers in the Prachin Buri area ? What is the cost per mat ? Any web sites showing this product ?

[JungleBiker]

Does anyone have experience with weed mats to prevent the growth of weeds around trees ?

Usually these are around 1 metre square plastic. They block sunlight preventing weed growth but allow water and nutrients to pass through to the soil.

Are there suppliers in the Prachin Buri area ? What is the cost per mat ? Any web sites showing this product ?

Hi Sibeymai,

I have never seen them in Thailand, but perhaps they exist? I think they are made of woven polypropylene, the same stuff as fertilizer bags and rice sacks, but they are usually black to prevent light reaching weeds underneath and treated with a UVI to prevent the sun breaking them down. Perhaps you could use fertilizer/rice bags and give them a coat of black paint? Just an idea. Though the paint may block the tiny holes between the weaves and prevent the water from soaking through. You may have to import them yourself. I know a British company that makes something like that: http://www.growingtechnologies.co.uk/groundcover.htm

It's probably cheaper to just use rice husks (plain or burnt), say about 5 cm thick, but don't let them come too close to the tree - allow about 5 - 8 cm gap - otherwise you may get rot problems around the trunk due to lack of ventilation. Once your trees are about a year or so old you can easily spray weeds with glyphosate, usually it doesn't do any harm to the trees if it touches only the bark; just don't let it touch the tree leaves.

Best regards,

JB.

[JungleBiker]

Hi Again,

Here's an endorsement for rice hulls:

http://www.sarep.ucdavis.edu/NEWSLTR/v8n1/sa-16.htm

And here is another idea for a mulching material using guinea grass (Panicum maximum or "yaa kini" in Thai) - seed is widely available in Thailand:

http://www.echotech.org/technical/az/aztext/azch5dry.htm

I intend to use a similar approach for growing agarwood trees in Laos. I will plant stylo 184 or "stylo thaphra" in Thai (seed also widely available in Thailand) in the alleys between the tree rows and then cut this and place as a mulch around the agarwood trees. Stylo produces less biomass than guinea grass but it is a legume so will fix nitrogen in the soil and the leaves and stems are fairly high in nitrogen, so besides weed surpressing, moisture conserving and temperature-moderating benefits the trees will also get fertilizer benefits.

If you have a large area of trees I reckon you could mechanize the cutting using one of those crude looking rotary mowers (the ones with the two big wheels) and attach a shield to deflect the cut vegetation into the tree row. A tractor with rotary mower could be used for bigger plantations.

JB.

[Pond Life]

Im currently experimenting with hessian (gunny)(burlap) sacks, theyre used rice sacks but cost a supriseing 30 B each.

I put them on top of our veggie patch.

The TGF says theres very little growing thru them after 3 wks but will have to wait another 3 wks before I go home & check.

[z9999]

Im currently experimenting with hessian (gunny)(burlap) sacks, theyre used rice sacks but cost a supriseing 30 B each.

I put them on top of our veggie patch.

The TGF says theres very little growing thru them after 3 wks but will have to wait another 3 wks before I go home & check.

I've always used a thick layer of newspaper, wet it thoroughly and place a layer of leaf mulch, or other mulch material over top. I find the newspapers keep the weed roots, if any appear from getting into the ground below and are easily removed. Depending on the thickness of paper I've found it to last for 3 years or longer.

[sibeymai]

Thanks all. I've used newspapers before on a home veggie patch and they've been very effective. However I need a solution on a commercial scale (800 rai so far). Am using rice husk at the moment but it gets blown away by wind and washed away by rain. Would prefer to use straw/hay but it is not available in the quantities I need at this time of year and what is available is very expensive.

I could use newspaper I guess. It's easily handled and does break down eventually and should be available in reasonable quantities. I wonder what it costs per tonne. It's not really attractive though, but probably no less than using plastic.

I wonder what sort of chemicals leach out of newspaper over time and whether this might be detrimental.

[JungleBiker]

Check this out:

http://www.ecocover.com

[sibeymai]

Thanks for the link JB. Interesting product. Will need to work out a few things like how long it lasts for and of course the price. Really prefer to source something local as shipping cost from NZ would be a factor. Like the idea of impregnated fertilizer, will have to ask what they use.

[chownah]

Soooooo what's your budget for mulching 800 rai?

Oh, by the way, from the link Junglebiker posted:

"Uniquely, EcoCover mulch mat is pre-enriched with an IFOAM approved organic fertilizer manufactured from deep sea fish waste. The mulch mat has sufficient fertilizer to provide a continuous application of nutrients to the soil during the mat degradation process."

Edited July 22, 2007 by chownah

[sibeymai]

Thanks Chownah. That a good "plain english" description of the fertiliser from the website....but I'd like a full chemical analysis before I used it.

Current cost of mulching 800 rai four times a year is 2,944,000Bt yearly.

[chownah]

Thanks Chownah. That a good "plain english" description of the fertiliser from the website....but I'd like a full chemical analysis before I used it.

Current cost of mulching 800 rai four times a year is 2,944,000Bt yearly.

Mulching 800 rai seems like a big job...how long does it take? How are you doing it (materials and methods) and what's your cost breakdown?

chownah

[sibeymai]

Chownah...1 person weeding, fertilising, mulching 4 rai per month. Cost above was for mulch (rice husk) only...1,150 baht per tonne. Fertiliser is about the same cost, then add labour, approx. 5,000 baht per person per month.

Leave you some mental exercise to do the sums.

Edited July 26, 2007 by sibeymai

[chownah]

Sibeymai,

I'm interesed in how this is working out. I guess you are putting 3 tons of rice hulls per rai....this comes out to about 2 kilo rice hulls per sq. metre which would be a very thin coverage so I guess you are not putting the mulch everywhere....are you puttin it around some trees?...and if so can you estimate what percentage of the ground gets mulched and describe how it is placed?...is it in continuous bands or is it in circles around trees...and about how thick is it being placed. Also, I'm interested in how long you have been doing this and in any observations (if any) you have made on what effect it is having on the soil or anything else....etc.

Chownah

[sibeymai]

Chownah,

2 kg in circles around the tree is correct (nice maths !). With mulching every 3 months the mulch will build up over a year to a point where the quantity and frequency (and therefore cost) can be reduced. 2kg covers not more than 0.5 square metres. For full thick cover of 1 metre square probably 5-6 kg minimum, but more initial cost.

With not more than 1 square metre around the tree mulched the percentage of total planted area mulched is around 20%. The rest is mowed by tractor.

Ideally I'd like to use straw when it is available and leave the husk as a base.

No effect on the soil. The organic material contributed from the rice husk appears to be minimal so we apply buffalo manure as fertiliser with the husk.

Only negative comment we've had is whether the husk will cause an increase in the temperature of the soil because of its density. It may if used in sufficient quantities, which is why I'd prefer to start using straw/hay for better ventilation.

We have only just started this program so the quantity of mulch around the tree is not great but what is there seems to be having the desired effect.

[chownah]

Chownah,

2 kg in circles around the tree is correct (nice maths !). With mulching every 3 months the mulch will build up over a year to a point where the quantity and frequency (and therefore cost) can be reduced. 2kg covers not more than 0.5 square metres. For full thick cover of 1 metre square probably 5-6 kg minimum, but more initial cost.

With not more than 1 square metre around the tree mulched the percentage of total planted area mulched is around 20%. The rest is mowed by tractor.

Ideally I'd like to use straw when it is available and leave the husk as a base.

No effect on the soil. The organic material contributed from the rice husk appears to be minimal so we apply buffalo manure as fertiliser with the husk.

Only negative comment we've had is whether the husk will cause an increase in the temperature of the soil because of its density. It may if used in sufficient quantities, which is why I'd prefer to start using straw/hay for better ventilation.

We have only just started this program so the quantity of mulch around the tree is not great but what is there seems to be having the desired effect.

From what I have heard and from my experience, mulches of any sort tend to reduce ground temperature beneath them because mulches in general are insulators and they keep surface generated heat from moving down into the soil. The only way I can think that a mulch could cause heat is if it was actively composting and this would only last for a few days unless you turned your mulch like you would a compost pile.......in short, I wouldn't worry about heat buildup.

chownah

[JungleBiker]

Hi Sibeymai,

Chownah,

2 kg in circles around the tree is correct (nice maths !).

Chownah calculated 2 kg per square meter not per tree, so the maths doesn't make sense to me!? But anyway there's no need to explain.

Only negative comment we've had is whether the husk will cause an increase in the temperature of the soil because of its density. It may if used in sufficient quantities, which is why I'd prefer to start using straw/hay for better ventilation.

We have only just started this program so the quantity of mulch around the tree is not great but what is there seems to be having the desired effect.

I agree with Chownah that the mulch will keep the soil cooler than bare soil because of the insulation effect, that's one of the many good reasons for applying a mulch. In this case the rice husks would also keep the soil cooler because they are light coloured so they'll reflect back some of the heat from the sun.

The rest is mowed by tractor.

So perhaps you should try my suggestion to grow stylo or grass and modify your mower to chuck the cut stylo/grass onto the tree rows, then you won't have to bother with the rice husks and if you grow stylo or other legume you will also get nitrogen.

JB

[JungleBiker]

this comes out to about 2 kilo rice hulls per sq. metre which would be a very thin coverage so I guess you are not putting the mulch everywhere....are you puttin it around some trees?

Ah, okay I get the maths now!

[sibeymai]

Good ideas there, thanks JB.