Biochar production and aplication in soils

Biochar production and aplication in soils

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Language: English

Type: Human

Number of phrases: 146

Number of words: 2772

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00:21
My name is Daniel Blackburn and today we're going  to talk about biochar. What is biochar? how do you   make it? what is it useful for? so let's get  into it! so, what is biochar? first of all,   that's very simple, biochar is charcoal,  so why don't we call it charcoal? the   reason we don't call it charcoal is  because we want to make a distinction   that biochar is not produced for burning  or for using as a source of energy,   or for barbecues. Biochar is produced with the single purpose of using it as a soil amendment.   So what does it do as a soil amendment? it  enhances the physical and chemical properties of   the soil and the biological properties of the soil  it increases infiltration rate, water retention,   it also increases the microbial biomass and  activity in the soil, and also the cation   exchange capacity (CEC) from the soils and  the ability of the soils of holding nutrients.  
01:25
It's a very useful amendment, and to make the  distinction with charcoal which is usually mixed   with some uh paraffin or other fuel to help to  ignite the *charcoal, the biochar is not mixed   with any fuel it's just simple charcoal made with  the purpose of being used as a soil amendment,   for helping the fertility of soils the  quality of the soils and the health   of these soils. Why use biochar instead of compost  for example, or other sources of organic matter?   the reason that we 'want'  biochar instead of compost or   vermicompost or other sources of organic matter is  that biochar is a long-lasting carbon amendment.   When you add crop residues, when you add compost  and/or any organic amendments for that matter,   organic amendments have a short life on  the soil in tropical climates in arid   climates, hot climates, the compost that you add  this year next year will be completely gone  
02:33
will be completely decomposed, mineralized, by  the soil microbes the advantage of the biochar is   that the biochar will not be quickly degraded by the microbes. It is resistant for being degraded by   soil microbes so we use that biochar as  an amendment for improving soil properties   not as food or as a source of nutrients for the plant/soil. If we use a compost if we use   a vermicompost we are actually stimulating  the microbial biomass by giving them food   and we are improving plant growth by giving  nutrients that are continuously being released   by the mineralization of organic  matter, but with biochar is different, we have   some amount of nutrients that are 'coming' but  not as much as you would get from compost   and the main use that biochar has is as as a conditioner of the soil properties improves the hydraulic properties of the soil it  improves also the chemical and biological  
03:42
properties of the soil so this is biochar it's  just charcoal that you use it for uh as a soil   amendment. How do you make biochar? first before * answering about how do you make it, where does it come from? you know, the idea of  biochar came from soils in the amazon forest   when you describe those forests they will normally...  these in the amazon forest, these soils are very poor    very acidic, with low fertility very sandy, continuously being washed by rainfall, but some soils in the amazon   forest were found to be dark, rich in organic matter very fertile, and further   description of those soils, led to the  discovery that those soils were anthropogenic   which means that humans made it, humans created  that soil, and how do they create that soil?   by adding charcoal. Tere is some controversy in if this process was on purpose or just a result of  
04:48
continuously slash and burn of the forest, and  then that led to an accumulation of black carbon   in that soil, but in the end result, is that thousands of  years later, that charcoal is still in the soil   and is still working as an improvement of soil  quality, and why don't we do it for the rest of   our crop soils? this is the rationale behind the international biochar initiative (*and climate change mitigation*)   so that's the reason why the biochar is being  proposed is a long-lasting soil amendment that   will improve the quality of the crop soils for the  hundreds and thousands of years to come,    things that we do now, will have a long-lasting  impact in improving soil quality , to make biochar, is the same way you would make charcoal, and you can do that at different scales
05:51
for different purposes so I will show you what  we are doing now in our labs, we do this for research purposes, but of course if you want to  do this for agricultural large scale purposes you   will have to use different systems so let's talk  about it starting from the smaller scale and then we   go up scale, in a way that we explain how this works to make biochar you have to bring organic matter   to a process called pyrolysis, pyro = fire lysis = breakdown so you are breaking down organic matter   by using temperature, this is the idea   behind the pyrolysis process so by  doing that, what you really want to do in order to optimize the process of burning  the least you can of the biomass, and keeping   the more you can as charcoal, you need to have a  slow combustion, with low oxygen supply burning of that biomass, so the idea of the  pyrolysis is that you have a slow combustion with  
06:58
a very limited oxygen supply, so what  will happen is that the type of carbon    on that organic material will turn into black  carbon which is very resistant for microbial   decomposition and will have all these properties  of increasing the water retention in the soil   and the colloidal charge in the  soil, so first when we do it on the lab let's  go for the smaller scale and move up to the bigger scale, when we do it on the lab we can do it in a furnace, and while we do it in a furnace we  can regulate the temperature ramp (in which   we increase the temperature) and we can change the time that is material is being subjected to that temperature   also and all these things can be regulated to study how these processes can impact the quality   and the properties of the resulting biochar so  that's the reason we do it on the furnace   
08:02
to do it in the furnace you need to have a can (which  we call a reactor) and this can must have a lid   in this can you will compact your biomass,  your dry biomass inside that can, and   you will cover it with the lid and the lid  will have just one small hole on the top   and what that will do is that the small hole  will allow some oxygen to get in but not too much   and then you will burn that at least for one  hour in the furnace at the temperature that you   want to regulate and at the end of this process  you will cover that hole on the top of the lid and allow it to dry, and then you can see how  much was left, how much was lost during the   burning process, the charring process, and by doing  this you will have very specific conditions where you   are producing the biochar, and you can study the  properties of this, the second type of system   is a system which is, you can have a reactor  which has an electrical power source, and electrical  
09:10
resistance, where you can heat up the material  using the electrical resistance and by doing   that you can also regulate the temperature and the duration that you're making *the biochar*  I will show you here the process of doing  this, Ahmed here in this image is showing the   the wood chipper breaking down this biomass so we  can compact it on the reactor, but you can use big   chunks of biomass, or compacted small chunks of  biomass, and depending on how you are doing it   you need to offer more or less resistance  for the oxygen to flow through this system   because if you have small chunks, and you do not  offer a good compaction or put it inside a can   or some closed reactor, that biomass will turn  entirely into ash instead of being charred so after you put your material inside your  reactor you just put it inside this stove and   regulate the temperature, and that  is it, at the end of one hour you can   
10:22
turn off the machine, wait for it to cool down  and then you have your charred material so before you use this charred material you  need to grind it down at a small particle size   the next type of systems that we have here in  the agricultural station is the one that was   made by the SQU research group of organic farming, from Ronda Janke and   it's a barrel style of reactor, and this  barrel, as you can imagine   it's just like a closed barrel with a chimney  in a way that you have the opportunity to   regulate the amount of oxygen that flows into  this *system*, so the procedure is either you   have a barrel where you put the biomass inside  you light that up when the fire has *caught up you put the chimney on top, and after a while  you close the oxygen input for that system   and let it burn with low oxygen, or you may have a  an another type of system where you have two chambers  
11:34
in the inner chamber you have a closed system  with very low oxygen input in the closed chamber   and the outer chamber you let all the oxygen  go in, so the outer chamber will play the role of   heating up the inner chamber and the inner chamber  will be the one that will be making the biochar   in all these systems that you that I described  for you, up to now   you're losing energy, all this heat from burning this biomass is just being lost   nevertheless there are several proposed systems  where you can recover energy *present* in this biomass   process and this energy can be recovered either by  gas and oils, or by the same heat that is produced   during this burning process, so i will  show here some images of some of these   where the pyrolysis systems, where  you can have them installed in large scale   and you have a double purpose of energy production  and the production of biochar so this  
12:41
is one of the main limitations that we have for  biochar widespread use if you use the the biomass   to make biochar, the energy yield is quite low  if you completely burn that biomass then the   you can multiply that energy yield a lot, so if  you by any chance have the purpose of generating   energy, most likely the systems that you will use will be completely burning  *the biomass* and not making biochar in that process, and when you make biochar in that process   because of the high profitability of selling  this material as charcoal, normally this   industry will opt to use the resulting  biochar as charcoal, not for agricultural amendments   and that is something. The only  way to go around this actually is by government regulation, subsidizing  this activity of biochar for improving the soil quality
13:50
moving from how you make biochar to how you use biochar to use biochar there are some things  you have to consider, biochar is actually   an alkaline amendment, so if you  have alkaline soils like in Oman   you might have some problems  of buffering this pH up, you don't   want your buffer pH up when you have already  alkaline soils, so how do you get around this   you include this biochar in the composting  process, or mix the biochar at the end of biochar is ready at the end of the composting, mix the compost with biochar and that compost will uh   regulate the pH of the biochar, and at the same  time, the charred material will   bind to the organic matter in the compost and  will help stabilize the compost   for the soil, at the same  time, so you can have this mixed purpose  
14:58
of having a biochar and compost mixed together, and  it will improve the properties of the biochar for   as an amendment for the alkaline soils that we have  here in Oman, but if you're using it for acid soils   the direct use of the biochar is also recommended and the only problem you would have for acid soils   is that usually acid soils have high phosphorus fixing capacity and by adding   biochar, the biochar will immobilize some of  that phosphorus when you recently add it to the soil   so you might have a slight negative impact of  decreasing the availability of phosphorus, when you   recently added it to the soil, so how do you get around that? either you mix it with organic   amendments, or you add some amount of phosphorus to that biochar so that biochar will   not act as a phosphorus sink, but as a phosphorus  source in the soil, so this are some of the  
16:03
things that must be taken into account when you  use the biochar: the incubation of the biochar   with compost or vermicompost before adding it to the  soil will improve its performance    and the things that you need to observe when you are using it   for acid soils or alkaline soils are different,  for the alkaline soils you were looking more   into the problem of alkalinization, and for the  acid soils it will act as a lime   but you may have some nutrient immobilization in the long term the biochar amendments will increase the carbon content in soils and this high   carbon content in soils will affect positively the chemical properties of the soil, the physical   properties of the soil and also the biological  properties increasing overall the soil health
17:07
increasing overall the soil health  so this is all I had to bring for   you today about biochar I hope you  enjoyed and see you next practical

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