Biochar for Your Soil

[WestCoastGal]

Hope you don't mind the double forum post. I originally posted a link to this Vimeo film on biochar under the Ohana section's Leilani thread because one of the main people in the film, Josiah Hunt, is from Puna, Hawaii. Josiah did a number of videos during the eruption on the BI. But upon watching it felt it would be beneficial to others here who might not visit that section of the forum. The film is available to watch for free through 10/12 at the link below. It will be shown Tuesday, June 23, at Stanford University if you're in the area and want to talk to Josiah after the film presentation (tickets being sold). The film is titled "Dirt Rich: Power Beneath Our Feet". The film will also be available for purchase. The film takes you from Hawaii to Sonoma, California where the production and practice of using biochar was being implemented even in drought stricken rice fields in California.

Link to limited time free viewing: https://articles.mercola.com/sites/articles/archive/2018/10/06/carbon-sequestration-biochar-for-soil-health.aspx

 

[joe_OC]

I didn't watch the whole movie, but did research on it.  Here is a study that I found was very interesting:

http://iopscience.iop.org/article/10.1088/1748-9326/aa67bd

Seems it helps crops in the tropics that are planted in acidic and nutrient poor soils.  The yield was an increase of 25%.  Though, there was no increase yield of crops in temperate climates.

 

[sonoranfans]

I started to use it in our high drainage sandy soil here.  I mixed some in with a copernicia hospita seedling I just put in the ground.  Unlike mulch activated carbon doesn't get digested by microbes so you mix it in and have permanent cat ion exchange capacity.  If your soil is rich or you mulch regularly its not going to make a difference. But if you don't want to mulch as frequently, and are in a warm climate where microbes eat organic matter rapidly,  it will help your soil retain micros for later use.  Sandy soil has little or no cation exchange for holding micros, this is just a way to lower mulching requirements as I see it..  One warning, it needs to be soaked in fertilizer water before use.  It comes without any ions so it will absorb nutrients in the beginning.  I've soaked it overnight in water plus some fast acting palm fertilizer before draining it down and mixing it with soil.

[joe_OC]

4 hours ago, sonoranfans said:

I started to use it in our high drainage sandy soil here.  I mixed some in with a copernicia hospita seedling I just put in the ground.  Unlike mulch activated carbon doesn't get digested by microbes so you mix it in and have permanent cat ion exchange capacity.  If your soil is rich or you mulch regularly its not going to make a difference. But if you don't want to mulch as frequently, and are in a warm climate where microbes eat organic matter rapidly,  it will help your soil retain micros for later use.  Sandy soil has little or no cation exchange for holding micros, this is just a way to lower mulching requirements as I see it..  One warning, it needs to be soaked in fertilizer water before use.  It comes without any ions so it will absorb nutrients in the beginning.  I've soaked it overnight in water plus some fast acting palm fertilizer before draining it down and mixing it with soil.

So what happens when the fertilizer that it absorbs is depleted?

[sonoranfans]

the idea is that you add fertilizer regularly and instead of it being washed away in sand, it is surface absorbed by the biochar and re released later.  Nutrients absorbed in the biochar will be in equilibrium with dissolved nutrients in the moisture in the soil until depletion occurs.  Just keep adding fertilizer periodically and depletion won't occur.  The key here is that the biochar keeps nutrients around and they are bio available, much like mulch which can also absorb nutrients and re release them.  The difference is that mulch is basically consumed by bacteria over time and biochar is not.  Biochar cannot keep soil as moist as mulching and it does not generate humic acid, fulvic acid etc like mulch does in degradation.  But in our sandy soil in west central florida 3 inches of mulch seems to almost disappear in one summer because the soil microbes are so active in the heat here and we have sandy soil.  

[Moose]

Suspicious of the benefits of biochar. At least I don't see the benefit to improving my soil. Plenty of carbon in the air, plenty of carbon in the soil's organic matter.

[tropicbreeze]

I use a lot of mulch, by the end of the dry season I'll have 20 to 30 cms on the gardens. That of course disappears in one wet season but apart from helping build up micro and macro soil organisms and increase CEC it also helps prevent soil erosion in heavy rain events. By the end of the wet season there's usually only bare dirt but with the heavy rains ended it's not a problem. Over the dry season there's a build up of plenty more mulch/leaf litter in the non watered parts of my property, much of which goes onto the garden. That helps insulate the soil from the heat and drying winds.

But I also incorporate as much biochar as possible into the soil. Like mulch it's a good nutrient sink. As with a lot of the tropics my soil is very poor. Any fertility is in the mulch and the biochar. The biochar acts as a buffer to the fluctuating amounts of mulch.

They say 'two heads are better than one'. I'd paraphrase that to 'two nutrient sinks are better than one'.

[sonoranfans]

20 hours ago, Moose said:

Suspicious of the benefits of biochar. At least I don't see the benefit to improving my soil. Plenty of carbon in the air, plenty of carbon in the soil's organic matter.

yeah if you have lots of organic matter, you don't need biochar as the benefits aren't needed.  Carbon in the air does nothing for cation exchange.  the benefits  of biochar are obvious(basic science) with millenia of slash and burn agriculture proving the value.  Biochar is only useful for those with unstable levels of cation exchange in the soil.  Sand doesn't hold cations at all, none.  If you are lucky enough to have constant high cation exchange, good for you.  If you have to mulch like a fiend to get it, there are smarter ways to do this.  The cation exchange of bio fhar lasts hundreds of years, not several months or a year.  I always prefer mulch on top as it traps moisture better, but if I want to reduce my yard work or change what I work on, the use of biochar is a good plan and it reduces the need for generation of mulch.   Commercial generation of mulch year after year creates LOTS more carbon than bio char( a one time addition).  So if you want to be carbon conscious, the practice of mulching is far worse than biochar.

[Zeeth]

7 minutes ago, sonoranfans said:

yeah if you have lots of organic matter, you don't need biochar as the benefits aren't needed.  Carbon in the air does nothing for cation exchange.  the benefits  of biochar are obvious(basic science) with millenia of slash and burn agriculture proving the value.  Biochar is only useful for those with unstable levels of cation exchange in the soil.  Sand doesn't hold cations at all, none.  If you are lucky enough to have constant high cation exchange, good for you.  If you have to mulch like a fiend to get it, there are smarter ways to do this.  The cation exchange of bio fhar lasts hundreds of years, not several months or a year.  I always prefer mulch on top as it traps moisture better, but if I want to reduce my yard work or change what I work on, the use of biochar is a good plan and it reduces the need for generation of mulch.   Commercial generation of mulch year after year creates LOTS more carbon than bio char( a one time addition).  So if you want to be carbon conscious, the practice of mulching is far worse than biochar.

How much biochar would you recommend for amending sand? I've bought it before at Big Earth in bags where it's finely crushed up, but I'm not sure the correct ratio to mix with my soil. 

[sonoranfans]

My first plantings are using around 1:2 biochar to palm and cactus soil mix.  I then mix in the existing sandy soil at 1/3 with the biochar /organic mix in a nice big hole(2 1/2-3' in diameter) that is not more than 18" deep.  On top of that I will top mulch as well to replace organic matter as it degrades and also to retain moisture better.,  Mulching doesn't have to be as frequent as without the bio char.  Currently I am adding mulch at about 1/2 the frequency I did before.  Eventually the bio char pays for itself and then some as I buy and spread less top mulch  The downside is that biochar needs to be put in when planting, I doubt it will work its way into the soil column like top mulch.

[Zeeth]

9 hours ago, sonoranfans said:

My first plantings are using around 1:2 biochar to palm and cactus soil mix.  I then mix in the existing sandy soil at 1/3 with the biochar /organic mix in a nice big hole(2 1/2-3' in diameter) that is not more than 18" deep.  On top of that I will top mulch as well to replace organic matter as it degrades and also to retain moisture better.,  Mulching doesn't have to be as frequent as without the bio char.  Currently I am adding mulch at about 1/2 the frequency I did before.  Eventually the bio char pays for itself and then some as I buy and spread less top mulch  The downside is that biochar needs to be put in when planting, I doubt it will work its way into the soil column like top mulch.

Thanks for the info! 

[Jerry@TreeZoo]

Does anybody have a source for large quantities?  Like tons or pallets of the stuff?