Burnt Rice Hulls

[Somtham]

My wife's uncle just bought a truck load of burnt rice hulls to use around his banana trees. The stuff looks beautiful. Jet black and the texture of coffee grounds. Does this stuff contain any nutrients to improve the soil and is it worth it to till some into the garden?

Thanks

[samuibeachcomber]

My wife's uncle just bought a truck load of burnt rice hulls to use around his banana trees. The stuff looks beautiful. Jet black and the texture of coffee grounds. Does this stuff contain any nutrients to improve the soil and is it worth it to till some into the garden?

Thanks

well it would n't hurt,am not sure about any nutrients left after burning though.I remember g/f uncle using the rice husks to cover burning old timber to make charcoal.

[Maizefarmer]

No harm done with most soils - very little nutrient but will help with drainage and get the density right and it will act as a pretty good sponge. Avoid adding to clay soil.

[Smithson]

Avoid adding to clay soil.

This is interesting, considering they improve drainage I would have thought adding clay would be a good idea?

[jaideeguy]

I, also would think that 'klab dam' would be good for drainage and therefore good for clay soils....plus add some potassium.

My standard potting mix is cow manure, clay soil, burnt rice hulls, rice hulls, and cocoanut shread and it grows good plants.

[Maizefarmer]

Avoid adding to clay soil.

This is interesting, considering they improve drainage I would have thought adding clay would be a good idea?

You mean't to say "adding to clay..." did you not?

Hang on - let me rephrase all this before someone jumps on me; burnt rice husk (versus unburnt rice husks - or straw for that matter) has considerably less bulk, volume/mass - it will compress a lot easier. And it also has a higher carbon content - significantly higher.

Clay soil conditions are more anaerobic than other soils (because of its moisture retaining capability and density).

The result: burnt rice husk/straw will quickly compress and then rot down in the anaerobic conditions.

Its all relative to some lessor greater extent: just how wet is the clay - just how carbonised is the rice husk/straw - how often can you turn the soil over (plough) - just how much organic matter are you adding - is it the wet or dry season blah blah blah blah - so someone can quite justifiably come back with an argument to show otherwise, but by and large it will rot down pretty quick in a clay soil - unless you add loads and loads, so much so that it would not be accurate to call the soil a "clay" soil anymore.

Any dry straw productwill do: roadside long grass, cut and chopped up in sufficient mass will do even better as it has greater bulk and bulk retaining capability. Rice harvesting leftovers are commonly used because there is so much of it left over and is a "free" by product of the rice growning and harvesting process, but in reality it offers little to no adavantage over other grass type organic products used as a bulk soil filler - even less so when it is burnt.

[Smithson]

Thanks for the explanation Maize, makes sense.

[jandtaa]

rice_husk_charcoal.pdfa little information on the benefits

[tftest]

shameless bump

klab dom.. can we see this as an alternative to making your own biochar?

Edited May 1, 2009 by tftest

[teletiger]

shameless bump

klab dom.. can we see this as an alternative to making your own biochar?

Good question. Is burnt rice skin biochar? Has it been carbonized, or is it ash? You could try burning some. Ash won't burn. I bought a few bags some months back, with that intention, but on opening them, discovered they contained at least 20% raw rice skin.

One of J's pfd's warns against overcooking the riceskin. (else it turns into a white ash?)

Regards.

[stroopeffect]

I've used many combinations of rice hull, rice char, cow shit as a substitue to whats avaliable in my area. For micro greens i used very well composted cowshit, almost dust (20%) and rice hull (80%). Helps to soak the hull overnight in water to absorb some water before mixing it and sowing the seed.

For irrigated melons i use alll three of the above mentioned 'ingredients'. After composting all together for a few weeks the mix goes into old fish feed bags which are rolled down to about 35 cm's. I used these in the dry season as the ground here is clay and will flood in the big wet.

Overall i recommend using rice hull to aid drainage and body if composted properly.

Sorry...in regards to rice char or whatever one wants to call it, i use through force of habit really. Back home we would allways add the fireplace ash to the compost. It's full of phosphorus and potassium which in combination with the neutral hull and nitrogenous cow shit well you should have a balanced NPK suited and mixed appropriately depending on what you want to grow and your crops needs.

Edited May 14, 2009 by stroopeffect

[tftest]

thank you.. that was actually very helpful

[IsaanAussie]

Today was a top day. I have made a successful batch of carbonised rice hulls to add to my soil improvement range. Really simple if you follow the rules. Hey Foreverford, where are you?

Anyway, anybody around me who wants to see how to do it come and I will show you. Maybe we should start "field day cum BBQs" for this sort of stuff and make a day of it. You can get a look at the worms, pigs and composting as well. The more the merrier.

Isaan Aussie

[Smithson]

Just bringing up an old post. IA, good to hear you've had success with the biochar. I've just built a gasifier, mainly for bamboo offcuts, but I will probably build a stove for rice husk.

Last year we were paying B3.5k for a small six wheel truck of 'gap dum'. The rice mill is charging 90 satang a kg for rice husks, so buying the ready made stuff is probably cheaper.

We tried to get another truckload, our regular supplier wanted B5.5k a truckload and we haven't been able to find anywhere else. I'm guessing the high price is seasonal, hopefully it will drop at harvest time. Although, I wouldn't be surprised if demand is increasing.

I'm interested in simple strategies for using biochar. When mixed with chook manure it absorbs all the odor and (I guess) this retains the nutrients. Does this mean it's better to use with fresh manure that has a stronger amonia smell? We have sheep and chook manure already bagged, to save work I was hoping to mix and spread on site, rather than composting it and then rebagging.

Ploughing in is difficult, so I was thinking to have a layer, then grow NFT/legumes and 'chop and drop', to add organic matter. Any thoughts?

[IsaanAussie]

Just bringing up an old post. IA, good to hear you've had success with the biochar. I've just built a gasifier, mainly for bamboo offcuts, but I will probably build a stove for rice husk.

Last year we were paying B3.5k for a small six wheel truck of 'gap dum'. The rice mill is charging 90 satang a kg for rice husks, so buying the ready made stuff is probably cheaper.

We tried to get another truckload, our regular supplier wanted B5.5k a truckload and we haven't been able to find anywhere else. I'm guessing the high price is seasonal, hopefully it will drop at harvest time. Although, I wouldn't be surprised if demand is increasing.

I'm interested in simple strategies for using biochar. When mixed with chook manure it absorbs all the odor and (I guess) this retains the nutrients. Does this mean it's better to use with fresh manure that has a stronger amonia smell? We have sheep and chook manure already bagged, to save work I was hoping to mix and spread on site, rather than composting it and then rebagging.

Ploughing in is difficult, so I was thinking to have a layer, then grow NFT/legumes and 'chop and drop', to add organic matter. Any thoughts?

Arh, me ol' boxing glove.

CRH is basically carbon so when you add it to manure the reaction between the N from the ammonia and the C from the biochar locks up ther nitrogen, less emission more NPK, less smell. My compost process is multistage. Raw manure, rice straw and hulls are added daily and always turned in the stage 1 box. That is covered with biochar (CRH) and sprayed with EM. Over the top is a layer of chopped straw to capture steam.

For manures you have bagged you could try a new process that I have started and now about to pelletise as organic fertiliser. You mix rice bran, soybean meal and the new PIG-EM I am brewing into the dried manure, or in my case pig manure composts. What happens is the probiotic or PIG-EM rips into both the manure and the protein in the other stuff and amplifies the NPK more than the local village sound system. Great stuff. Once it is mixed you rebag it for about ten days so it is almost anaerobic and it gets as hot as hell. When it cools down, good to go...

Producing CRH or carbonised rice hulls is a regular part of my week. I burn 20 odd bags of rice husk every week for a yield of 10 bags of CRH. I get my hulls from the local rice mill and pay about 20 baht for enough bags to fill my pickup. Only other equipment needed is a kero tim and a bit of pipe, plus enough water to stop the hulls becoming ash. One burn of 10 bags of hulls takes about 4 hours for me.

Gasifier stoves are a great interest to me. I have a friend in Vietnam who produces a stainless rice hull stove for sweet BUGGER all. I am waiting the commercial release of these units and hope to localise production here. Pardon the pun, but a little on the back burner at the moment.

I have started making my own soil. The local stuff is rubbish. Over the last few years I have baled the rice straw and have produced mushrooms and other stuff but always the straw ends up is humus rich soil. So I built up raised beds using bales as the edges and filled them with compost, soil, biochar, and worm compost blended together. Theory being that by the end of the wet this year this year I will rotary hoe the lot into the crappy stuff under it and start again.

Edited April 7, 2012 by IsaanAussie

[Smithson]

The gasifiers are certainly interesting. I've been reading about the small units, could fit in very well here, save a lot of time and money buying gas/charcoal. If you've got any for sale let me know, I'll swap you for a pair of gloves .

This is the unit we've built http://biocharproject.org/biochar-technology/tlud-gassifier-awesome-modifications-karl-frogner-phd/

The first run produced char, but also lots of smoke, I think the rice husks might be too fine and not allow enough air. I'll try it again with bamboo offcuts.

The compost you describe sounds good, but we have about three rai and I'm too lazy to do all the turning. My thoughts were to do everything on site, adding the biochar/manure then growing the legumes/NFTs and just chopping growth, creating humus layer.

[harrry]

Forgive me if I am wrong but this would only seem to be adding to the problem of smoke haze and global warming. Does it have a place in sustainable agriculture.

[Smithson]

^ Done properly there should be almost no smoke. The heat generated can be used for electricity or cooking, then you are left with charcoal, which locks up the carbon and is an excellent soil conditioner. Biomass left to rot will quickly return carbon to the atmosphere.

[IsaanAussie]

Forgive me if I am wrong but this would only seem to be adding to the problem of smoke haze and global warming. Does it have a place in sustainable agriculture.

Well actually yes it does have a place in sustainable agriculture. If you burn your rice husks under your fruit trees the trees benefit.

If you want to reduce the smoke you can fit a collar on the chimney and fill it with sawdust.

[IsaanAussie]

The gasifiers are certainly interesting. I've been reading about the small units, could fit in very well here, save a lot of time and money buying gas/charcoal. If you've got any for sale let me know, I'll swap you for a pair of gloves .

This is the unit we've built http://biocharprojec...rl-frogner-phd/

The first run produced char, but also lots of smoke, I think the rice husks might be too fine and not allow enough air. I'll try it again with bamboo offcuts.

The compost you describe sounds good, but we have about three rai and I'm too lazy to do all the turning. My thoughts were to do everything on site, adding the biochar/manure then growing the legumes/NFTs and just chopping growth, creating humus layer.

The rice husks are just fine. The smoke is the result of the burning of gases coming from the husk. My burner, not stove, is a simple kero drum and a cement pipe. I pile 10-15 bags of rice hulls around the drum once a very small fire is alight inside. Got some pictures somewhere and some details to make one up including the smoke arrester. I am too lazy to worry about that!

Turning compost and moving it from box to box is a few hours a day for me, every day. My compost "in progress" totals around 6 cubic metres. Why do I do it? Because the sales cover more than ten per cent of my pig feed bill. Lots of alternate methods though where you dont need to turn it. I have tried a few but none produce the results anywhere near as quickly.

The gasifier stoves I have got an interest in come in 3 sizes, the smallest being 6inches in diameter and has a price tag under 1,500 baht. Now, they produce a lovely blue flame and definitely no smoke. They are supposed to allow about 45mins cooking time per fill and the temperature is regulated by the small fan speed setting.

[Smithson]

Aussie, I would be interested in a cooker, but preferably one without a fan, to make outside use easier.

[cooked]

As the subject is 'Burnt Rice Hulls - good or bad as a soil conditioner' I'll plunge in . My ex-girlfriend was an archaeologist and specialised in studying soil sediments from prehistoric sites. In clay sediments under a microscope she was able to identify carbonised seeds that were over 2000 years old. So not much point in hoping that mixing this in will be much use in bettering clay soil. The soil in Isaan is very clay, a problem that I have here in Switzerland occasionally. (I am a landscape gardener heading rapidly towards retirement). Having realised that the toilet cleaner that I had bought contains hydrochloric acid, I poured a few drops here and there onto the baked solid soil in what is to become our vegetable garden. A lovely reaction, bubbling and frothing away, so the soil is alkaline, very much so.

Next step: the building sand, using the same test, didn't react at all, so this is probably from a river somewhere and is acidic. No harm in adding this to the soil at all, in fact it works miracles. Just don't add alkaline sand, this is the stuff that kids hate as it also bakes solid in a short time and has to be dug into again and again and won't help at all.. You have, from a gardener's point of view two opposites; very heavy clay soil and very light sandy soil. Get the mixture right and organic stuff like rice husks, cow manure will be able to rot and release the nutrients into the soil. 1 -2 centimeters on top will do it, sometimes just weeding will be enough to work the sand into the soil. Wood ash is also ok, but makes the soil heavier.

The main use as far as I am concerned, of rice husks, is in keeping weeds down and keeping the soil moist in spreading a few centimeters of it around trees and shrubs

[Smithson]

Regarding the carbonised seeds, biochar is not supposed to break down, it's a soil conditioner rather than a fertilizer. the idea is that it stimulates micro biological activity.

[IsaanAussie]

Aussie, I would be interested in a cooker, but preferably one without a fan, to make outside use easier.

Hoping to have a unit here next month from Vietnam. The fan this uses can be run from mains or a motorcycle battery so portability really isnt an issue. It is top lit updraught in operation. Will post some pictures when available. Idea is to localise production.

There is a lot of information of a side draught unit that was built by the Asia Institute of Technology. It consists of the gasifier, a gas burning chamber and a series of cooking outlets where the hot gases do the work. That is a top feed unit that can be refuelled and has the capacity to be used for large catering, like schools etc... There are plans for that around somewhere on the net.

CRH contains two important elements for the soil, carbon and silica. Rice hulls rot slowly because of the lignin coating. It is the lignin that pellet making machines use as the binder. CRH in manure based compost is brillant because the carbon reacts with the ammonia and traps the nitrogen. No smells and higher nutrient value. The micrtobes in the compost then convert the nitrogen into a plant usable form. At least that is my understanding..

[cooked]

Regarding the carbonised seeds, biochar is not supposed to break down, it's a soil conditioner rather than a fertilizer. the idea is that it stimulates micro biological activity.

yes I understand that, thanks. I was, in my usual rambling way, trying to suggest that if the soil conditions do improve due to the use of biochar, then they will indeed break down biologically, The best solution is sand, believe me

[loong]

Land near my house was idle for many years and the locals had a few charcoal pits on it. The owner decided to plant sugarcane and the bio-char residue from the charcoal pits certainly helped the soil.

I have attached a few pics and the improvement is obvious I hope. You can see the growth difference in the areas where charcoal was made.

The land is now planted with cassava. The effect is not so obvious now as ploughing has left the biochar less concentrated.

Burnt rice hulls are much the same as the charcoal residue, so can only improve the soil.

[cooked]

absolutely, where wood has been burnt, most crops grow better, this is at the root of the slash and burn farming method, used in Europe up until the middle ages. I still have to be convinced that burnt rice husks improve soil quality in the long run though. I promise to try it and let you know.

[IsaanAussie]

OK, right here,right now. Come and look. My land treated with CRH has grass standing at two feet high inside two weeks. Forget the future carbon credits and the rest of the BS, carbon sequestering works.

[Smithson]

Yesterday we did three loads of scrap bamboo in the gasifier, the locals were pretty surprised because making charcoal for them usually means lots of work and smoke. We used a drop saw to cut small peices, but a chipper would be ideal.

Would be nice to make a unit that was also an oven for cocking pizzas and roast.

I have seen pics of the aiit gasifier. There is also one that fits on a pallet and generates electricity. This is open source, so plans should be available.

My Bil told me in Kalasin a six wheeler of biochar (rom rice husks or sugar cane) is only B800.

[loong]

Yesterday we did three loads of scrap bamboo in the gasifier, the locals were pretty surprised because making charcoal for them usually means lots of work and smoke. We used a drop saw to cut small peices, but a chipper would be ideal.

Would be nice to make a unit that was also an oven for cocking pizzas and roast.

I have seen pics of the aiit gasifier. There is also one that fits on a pallet and generates electricity. This is open source, so plans should be available.

My Bil told me in Kalasin a six wheeler of biochar (rom rice husks or sugar cane) is only B800.

That is great, bamboo offcuts normally cause the worst fumes when trying to make charcoal. Some years ago, when i lived in Phrae province a neighbour was making charcoal from bamboo and it was impossible to stay in my home. I was forced to complain to the local health dept and they shut him down.