Actually, that is an interesting idea when it comes to fruit trees and clay. One of the issues I mentioned earlier with planting containerized trees or amending soil is creating a pond. One thing I’ve seen folks do is to create mounds to plant fruit trees.
Now, what if we took the Hugelkultur idea and accelerate the process. What if one use a bottom plow to create a trench. Then found a technique (not sure of the mechanics) to perform an oxygen deprived burn of wood chips in the trench to create biochar. Then added the charging agent (compost, or whatever) and then pushed the soil back over the charged biochar.
The mounding would solve the infiltration issue and the charged biochar would deal with the issue of the N tied up by slowly decaying wood.
When they create logging decks, if we don’t include special instructions in the contract, they leave large piles of a mix of wood debris and topsoil. These are basically dead space for quite a few years, but eventually after enough decay occurs, they become fertile areas for native plants.
When hardwoods are clear-cut woody debris from the tops are generally left. We usually windrow these. A wood chipper would make these a perfect source.
If I remember correctly the amazon natives did make biochar in pits and through plants over the fire to deprive it of oxygen. I added biochar on top of the dirt and did not till it in with all new tests under cow manure / compost and woodchips. I did not charge it. Old plots I added biochar in the soil and it’s showing signs of drastic improvement.
Thanks. The little reading I’ve done says you can make it in a pit. They say the process is less efficient than in a TLUD kiln and the process works differently. A TLUD is completely loaded at the start and the up draft comes from holes in the bottom of the unit. In a pit, a fire is started and once hot enough, the biomass is added in layers to create oxygen deprivation. One basically has to tend the fire. I’ve seen pictures of cone shaped open metal above ground kilns based on this design that are supposed to be a bit more efficient than a pit. I think a TLUD gives me more flexibility. It is portable enough to take to a site if all the material is available there, or I could use it at a central location and transport the finished biochar. I think it requires a more consistent material like wood chips than an open pit which could handle a mix of biomass.
The trials I’ve done using biochar are all with cherry and plum. My mom grew peaches years ago in biochar from seed. She had high success rates growing peaches from seed using about a 50/50 mix with dirt. She grew lots of peaches.
On a side note my grandpa when he was alive said be careful with ash, charcoal etc because pawpaw, persimmon , peaches etc are all very different in requirements. He grew a persimmon and pawpaw orchard once and where Limbs touched they died because pawpaw and persimmon are not friends. Wood ash and I suspect biochar to is a mild form of lye as many of you know which is fine with a peach but maybe not with every other tree out there. I would not try it on more than one pawpaw.
I’ve been using that approach for a few years. I love the results, though I have very good drainage I like the elevation (though I do small ‘mounds’ versus large ones) and the introduction of microbes that hugelkultur promotes. My trees, shrubs, blues, raspberries and even ornamentals all sit on a ‘shelf’ of wood, of various sizes (based on the planting) and degrees of decay. When I move a plant, I move its wood along with it, as the roots are usually lovingly wound all throughout the buried wood. Worms galore too.
I usually use pine or hardwood too buggy or moldy to bring into the house to burn. I also scavenge likely pieces from my neighbors, who think I am insane I suspect. I had mentioned this to Alan a few days ago in clarifying how I feed my apples - their wooden footing is their food.
Jack,
I don’t know why this didn’t dawn on me earlier when you mentioned ag uses for biochar and introducing OM. When we grew sod, after harvest the soil would be compacted from many heavy trucks and having a high clay content without cover the sun would bake it to almost pottery. We would harrow the ground to knock off the high spots and then drill in sweet clover. This needed to be accomplished by mid-late July so the clover would germ and get far enough along to get one growing season before winter. The next year the sweet clover was disked as soon as the white bloom was finished and replanted to grass. Because of the extensive and deep root system sweet clover has, the compaction was relieved and as an added bonus the clover was an excellent green manure along with fixing 60-80# of N. We seeded at 30# of seed/acre, about double recommendations. We found the plowdown green mass and root system kept us from having to use herbicides and fertilizer for the year after the sweet clover. We did this on fields up to 80 acres. If you wanted, the clovers could be plowed(tilled) down before the white blooms but we had 40 colonies of bees on the clover and the honey really helped the profitability . Just an idea that I have used that worked well and could be used for ag and consevation too.
Rotating legumes and grass crops is a well proven technique. Farmers rotate corn and soybeans regularly which is the same concept. I’ve converted some old logging decks that had the topsoil removed before we purchased the property. I found rotations of buckwheat in the summer followed by a mix of winter rye, crimson clover, and daikon radish in the fall let me improve the decks from places that would not even grow weeds to acceptable fields.
The problem I found with plowing clovers is that although it pushes the OM deeper, it also introduces oxygen which causes microbes to consume it much faster.
My hope is that biochar, properly charged, would be a one time incorporation. Again, for now, I’m just hoping to experiment with it on fruit trees.
Yes, I’ve been to classes on biochar and talked to many people who use it. I intend to do the same. The idea is that the biochar is a holding area in your soil to allow minerals and microbes to make their home so the roots and mycorrizae can use it. It will drain better than our clay soil here and breathe better too. It does tend to have a light alkalinizing effect on your soils, so don’t put it near your blueberries. The guy in the class showed us you can get a 55 gallon drum and just buy a smaller garbage can, filled with wood or other organic matter. Then fill around the big drum with other wood and put the smaller metal garbage can in it, so the outer wood starts the fire and burns the stuff in the garbage can without oxygen.
Charging it before using it in the soil is nearly universally recommended. The two most common nutrients to charge it with are urine and compost tea. You want to make sure that the biochar has nutrients in it so it doesn’t suck all the nutrients out of your soil. It’s like adding sugar when you can fruit. In the long run, it would be ok without it, but your plants might suffer in the short run. They usually do.
Hugulkultur is also highly recommended. Moreso for northern areas where the wood in the soil doesn’t rot so quickly. In the north you can do either. In the south, biochar is more recommended, because it really doesn’t decay much for the first 700 years.
John S
PDX OR
Thanks John! I just saw a post on another thread yesterday where a guy used that method of can in can. So now I’ve seen the TLUD kiln, the inverted cone kiln, and now this can-in-can kiln. Did any of the classes you attended talk about the relative efficiency of thee kilns? The advantage I see to the inverted cone is that one could dig a hole at the site for the kiln and get some pretty good volume. I guess one would need to transport the charging agent to the location though. The disadvantage is that you need to tend it and continuously add biomass. I do like the TLUD kiln because you fill it at the start and once ignited and closed, you can walk away until it is cooked. Does the can-in-can kiln work similarly? Do you put some amount of holes into the inner can?
Yes, there are holes in the inside can. I think the main advantage is that you can do it in a suburban/urban area. It takes less space, and the neighbors don’t have the right to call the fire department because it is enclosed. The people I’ve talked to said it helped their soil, productivity and decreased diseases. I’m all for all three of those things.
John S
PDX OR
The bottom is just a 50 gal drum with holes drilled in the bottom. It sits up on cement blocks for good air flow under it. A neighbor had some tree work done so I had the crew dump the wood chips in my back yard last summer. I loaded it with the wood chips. Unfortunately they are wet at this time of year. I figured it would still make biochar but I would have smoke and the process would go slower.
The top section (after burner) is half another 50 gal drum. I made slices up along the bottom and used vicegrips to slightly bend them outward so it would fit over the drum. Next I bought an 8" duct work collar and a 2’ section of 8" duct work. I placed the collar in the middle of the top of the afterburner and traced a circle around the inside on the drum. I then used a sawsall with a metal blade to cut out the circle. I used sheet metal screws to secure the chimney to the afterburner. I sit the top fire and let it burn for a bit and then placed the afterburner section on top.
Here is the resulting biochar. I poured it on the ground and soaked it with water to put it out. Rather than taking an hour or less as shown in some of the youtube videos, this ran overnight. I think this is largely due to the wetness of the woodchips. I left one load burn too long and got almost all ash. After a while I caught on to the timing. I typically light it up at about 7:30 pm and shut it down about 9:30 am the next day. This is about right with my current moisture content.
This post is getting long, so I’ll make another for the next steps…
My plan is to use the biochar with some trees I’m growing. I’ll be directly amending the mix for container plants and amending the hole when planting. My reading says that if you don’t properly charge it, it will actually leach nutrients for the first couple years making them unavailable to the plants. It seems like the optimal mix is a 20:1 C:N ratio for direct amendment and 25:1 to 35:1 for amending compost.
Given I’m starting with wood chips, I’m estimating the raw biochar to have a 100:1 C:N ratio.
I decided to use urine to charge it. Most of the disease issues with urine seem to be related to fecal contamination during collection when done from sewage systems. Human urine is pretty much sterile when it leaves a healthy human body. So, I decided to do direct collection. I found 1 gal Open Pit Barbeque Sauce containers to be perfect for collection. They have a large mouth and heavy duty handle that holds them in just the right position.
I made enough runs to collect about 15 gal of biochar and put it in a 19 gal storage tub. I then started collecting urine and just pouring it in. Unfortunately, I decided to go this route before I did the math. On a good day when I’m around the house most of the day, I can produce about 1/2 gal of urine per day. After doing the math, I estimate I’ll need to add about 30 gal of urine to get the right C:N. Eventually I’ll get there, but I’ll need another method for my next tub. The fact that it is slow actually helps. 15 gal of biochar obviously could not absorb 30 gal of urine at once and certainly not in a 19 gal container. So, I just add a gal every couple days and allow the water to evaporate out. Every few days, I dump the entire tub into a second tub so the contents end up inverted. I also use a shovel to chop and stir the best I can from time to time.
I’m now started to fill a second tub with pure biochar. I know I have some water soluble Ammonium Sulfate in the barn. I’m now trying to do the math to figure out how much of that I would need in place of urine.
My final step will be to dig to the bottom of the pile of chips. I’m sure some of it has composted. I’ll make some compost tea and add that to the biochar to get some microorganisms going in it before using it.
Just thought I’d share what I’ve tried so far. I’d be happy to hear and advice or pointers from folks who have used biochar.
The biochar shouldn’t reduce N content of soil appreciably because it is rather stable. Any breaking down shouldn’t touch the needle of N content in your soil as I see it (not that I’m a soil scientist but this seems pretty clear). Also the N to C ratio would shift in favor of N in the process of the burn as the carbon is returning to the atmosphere as carbon dioxide when heat is created.
Save you urine for direct feeding of plants in spring. Gas containers also work well.
I’m hoping that you will do a comparison of char and char free plants but if the char is fortified with urine the comparison will be meaningless.
Late to the party…
I have been researching biochar for a few years, and have incorporated it into compost piles, used it as animal winter bedding, potting soil additive, and applying in planting holes and trenches.
I can harvest unburnt coals from my woodstove and wood fired outdoor oven, I do want to try the open pit method of production this season as I have quite a brush pile from fallen pine trees.
My soil is acidic, so the sweetening effect of biochar helps bring the pH up.
I used quite a bit when I installed asparagus 4 years ago, those plants have been growing strong ever since.
As a potting mix ingredient, I hoped to replace perlite but this did not work out, the growth was stunted and I may have used too high a ratio.
In the chicken coop, pigsty, it helped absorb odor very nicely, and gets charged with all that manure-y goodness.
I appreciate the feed back. I’m not a soil scientist either. I’ve done a bunch of reading on biochar but I’m limited to that. I don’t have any hands-on beyond what was described in this thread. Here is a quote from a paper targeted at laymen like me from James Joyce, a PHD chemist.
“Organic materials and biochars share a common characteristic. When first added to a soil, they suppress the nitrogen available to plants. For organic material, this is largely due to a surge in microbial activity in the presence of readily available organic carbon. For biochar, this effect is combined with in fact, dominated by chemical adsorption of nutrients into the char, which extends beyond just nitrogen to affect most nutrients. For this reason it is very unwise to add an unconditioned biochar directly to soil without adding compensating nutrients at the same time.”
The same paper recommends a C:N of 25:1 to 35:1 if you plan to compost with biochar. It says that adding biochar without conditioning is a gamble that depends on your current soil conditions and the best way to use it is to condition it so that it is optimal for microbial life before you add it. The first step is to balance the C:N ratio as you would with compost. It suggests that if you are adding directly to soil, it is better to shoot for a 20:1 C:N.
I’ve done a bunch of other reading on it and I have found lots of references that support what this paper says and I haven’t found anything that is well grounded that refutes it. This paper is my starting point because it is dumbed down to where I can understand it. Here is the link if you’re interest in the paper: Conditioning Biochar for Soil Application
The second step is to add microorganisms to the biochar. Personally I see biochar as a home for microbial life rather than a significant mineral contributor. I have heavy clay soils that have low OM. In my fields, it takes many, many years of rotating grasses and legumes with minimal tillage to even raise OM a little. While I don’t currently see the economics to make this worthwhile on an acreage scale, I’m thinking I may be able to apply it to fruit trees since the volume is much smaller and I can produce it myself.
I was originally planning to use compost tea for the second step of adding microbial life, but it looks like I may have stumbled on a local farm that deals in worm castings. I’m now considering making a worm casting tea brewer and using worm casting tea for this.
I will be doing a test with my containerized trees, but the test won’t compare adding raw biochar as I don’t think that is useful. Instead my test will be adding the charged biochar to my mix verses growing trees exactly as I do now. I don’t expect the biochar to provide the advantage. I expect the biochar to help the mix retain the microbes and nutrients which in turn I hope produces a positive effect.
I considered the open pit method. There are lots of kiln designs that work. The reason I chose the TLUD kiln was because of time. Most of the cone shaped kilns (a pit is an example) are open and require continual loading and attention. The TLUD design lets me load it, light it, and leave and go do other things.
Have you seen results from your use of biochar compost?
That quote itself is extremely inaccurate. Only organic materials with a high C to N ratio do this, but I assume he was talking about the types of materials that are like this- it’s out of context, after all.
Thank you for the clarification, I was not aware of the current state of the science on this topic. I’m still awaiting clear confirmation of its efficacy, but now I don’t expect to get that any time soon giving the range of biochar formulations and the difficulty to know what it is actually doing what if you are fortifying it with soon to be urea.
I’m sure when the efficacy is clear it will be endorsed by the ag universities in this country. Right now, I wouldn’t want to add something that absorbs available nutrients in an unpredictable manner if I wasn’t sure of an upside.
Usually there are clear ways to deal with problem soils and usually you get more bang for the buck from organic matter by putting it on top of the soil- but heavy clays can be challenging. I simply rely on raised beds and sometimes even massive additions of sand (which the literature discourages but certainly works if you bring enough sand).
With the addition of a cubic yard of sand you can grow a fruit tree in most any clay- the hard part is incorporating it.
The link below does make biochar an enticing possibility.
I agree. I believe he was referring to thigh C:N ratio materials as well. There have been a lot of tests run with biochar in different percentages run but with containers and in the field. After my reading, I don’t expect biochar to be a significant nutrient contributor. Mycorrhizae seems to be a big area of research. The complexities are well above my pay grade, but it seems there is clear evidence that this symbiotic relationship between soil microbiology and plant growth is beneficial.
Rather than trying to understand the detailed symbiosis between plants and the microbiome, my approach is to simply use bichar as a structure to aid my soils in their ability to support microorganisms. My intent is not to evaluate bichar in general, but to evaluate my current growing technique against one that has more active microbiology. Biochar is simply a mechanism to achieve that for me.
I have a brother in law in Austin Tx who makes his own and swears by it for raised beds However, he loads it with azomite and compost before use. He grows papaya and garden plants with better success than where it is not used. in high pH areas char can be detrimental even with the azomite because micros can be tied up too much. I live in one of the high pH areas. State of Texas agronomists say most of the benefit of char, where there is a benefit, comes from its ability to raise pH long term. Basically, I am suggesting you know your soil before deciding to use or not. I do not think my brother in law has done trials comparing loaded biochar to azomite and compost alone.
. Just an idea that I have used that worked well and could be used for ag and consevation too.
