Most cost effective way to build soil carbon

I bave come to the conclusion that you cannot add om to the soil you can only grow it.
The soils with the highest om are bogs where the conditions are anaerobic follwed by acid soils so lack of air and low PH prevent decomposition. Consider the typical farming scenario in that a ley is ploughed up and ususally has its PH 'corrected' before being brought into arable. This starts the rot literally which is then exacerbated by high input low biological return crops so you are onto a downward spiral.
Manure may be added and usually ploughed so the cycle continues and as is the way you have selected for a carbon hungry soil fauna. This is the problem, how to add carbon in a semi anaerobic way. It must be by roots to be effective and not by tuber types which rot and let lots of air in. The chemical make up of the roots is also probably a factor i suspect that roots higher in silica may decy at a slower rate but its only a thought.
The quickest way would be by LOW INPUT deep rooting crops be they forage or cash. High inputs just stoke the fires in the soil and get the wrong fauna going. Some soils take abuse much better than others and can take more of the high input system but most will decline to a resting level of about 2%.
If you think that everything above the soil is worm food and everything below soil food i dont think you can go wrong.
 

conor t

Member
Depends how many generations you are prepared to wait

"results show that when Miscanthus is grown on land previously under arable agriculture, the soil organic C will increase to a level above that of native pasture, as Miscanthus organic material is shown to have a slow decomposition rate"

Taken from http://onlinelibrary.wiley.com/doi/10.1111/j.1757-1707.2010.01033.x/full
Be careful reading articles like that that dont have very long term results to back up what they are saying.
That model is flawed in that it assumes om is increased by slowly broken down fractions when thats not the case, simple sugars can last for decades and lignin can be broken down in under a year under the right conditions.
 

bactosoil

Member
soil carbon levels will be affected by biological variations in sequences (not ratios ) which is also variable zonally and if out of kilter cause depletion , applying Pas 100 compost can actually exasabate a problem rather than solving it, while in peat bogs biology can self regulate and minimise carbon degredation .
 

IEM

Member
Location
Essex
that all sounds like a sound plan, Listening to a gabe brown interview yesterday I think I wouldn't bother measuring OM, and instead go for water infiltration. Mainly because you can do that on farm cheaply and quickly, and you will struggle to have one without the other.
Infiltration will certainly be interesting to measure and see changes. Will be p,k and pH testing whole farm in spring and can get OM tested for an additional £1/ha I believe so will do this as well
 

IEM

Member
Location
Essex
Depends how many generations you are prepared to wait[/B]

"results show that when Miscanthus is grown on land previously under arable agriculture, the soil organic C will increase to a level above that of native pasture, as Miscanthus organic material is shown to have a slow decomposition rate"

Taken from http://onlinelibrary.wiley.com/doi/10.1111/j.1757-1707.2010.01033.x/full

I want to build it as quickly as possible! It's a long term project but hoping for some clear improvements within 5 years
 
IEM, On first reading the OP I thought you were wanting to increase the OM with a view to it eventually being available to your crops. I then wondered whether your aim is to sequestrate carbon in the soil that will not break down for a very long time. One of the things that made me wonder this is the use of heat treated compost so that as Clive posted at #20, it is carbon without the benefits of natural vegetationthat is composted without heat - a type of biochar in fact.

What is your aim, plant food or carbon sequestration?
 

IEM

Member
Location
Essex
IEM, I think the only thing you have misssed is reading Robert Elliott's book. His grass seed mixes were very complicated though and I think not necessary, but I accept he was far more knowledgeable than me about such things. Sir George Stapleton thought they were complicated too, so I am not alone.

My quote of my own writing (at #36) showed an increase of OM from 1.3 to 4.5% in only four years so you will not have long to wait. I did have some Puna chicory in the mix but not plantain. It was basically perennial ryegrass (forget the variety without checking records) and Haifa white clover, which I had successfully used in Australia. It was sown in late 2005 and after cultivating it out the 2010 test showed the 4.5% OM. It still tested 4.5% in 2014 but with higher pH and elevated P and K levels. It had been planted to olives in the spring of 2011, so no further grazing, but well fertilised. I do a simple NPK, pH and OM content test on all fields every 4 years. I also do a more detailed leaf analysis of trees if I feel it is appropriate. The trees will soon reach the size where sheep grazing can be permitted, but not goats for quite a few years - if ever. They eat everything in reach and that is more than 6 feet from the ground.

If you are using leys and then some cropping I do not see the need to apply compost to grassland - or perhaps I am misreading you, and you intend to apply the compost to land in the cropping phase as Elliott did? I relied on a small amount of concentrates fed to the goats at housing each night to provide some of the trace elements in their droppings, and the lime and most of the fertilisers I use have a good range of trace elements in them. N.B. Housing of small livestock at night is essential because of the number of large dogs that wander about, sometimes in small packs.

I have never grown Miscanthus, but did consider it on a couple of occasions and decided against it. I agree with what Courier posted. Plenty of undecomposed OM, a bit like maize I suppose, but it takes a long time before that OM becomes available to your following crops. I still find the crown and thicker pieces of the stems of maize several years after having last grown it in four fields.

I have previously read some of Robert Elliot's book (found it a bit heavy going but will give it another go). Currently reading Fertility Farming by Newman Turner, similar system and a great read with a lot of relevance today.
He was a big believer in compost although I'm not sure what he would think to the green waste compost I am importing! I am applying compost during the cropping part of the rotation not to the ley as I feel this is the most beneficial time to do it. Newman Turner however applied some compost in the 3rd year of his 4 year leys as well as a larger amount in the cropping phase.
 

IEM

Member
Location
Essex
I bave come to the conclusion that you cannot add om to the soil you can only grow it.
The soils with the highest om are bogs where the conditions are anaerobic follwed by acid soils so lack of air and low PH prevent decomposition. Consider the typical farming scenario in that a ley is ploughed up and ususally has its PH 'corrected' before being brought into arable. This starts the rot literally which is then exacerbated by high input low biological return crops so you are onto a downward spiral.
Manure may be added and usually ploughed so the cycle continues and as is the way you have selected for a carbon hungry soil fauna. This is the problem, how to add carbon in a semi anaerobic way. It must be by roots to be effective and not by tuber types which rot and let lots of air in. The chemical make up of the roots is also probably a factor i suspect that roots higher in silica may decy at a slower rate but its only a thought.
The quickest way would be by LOW INPUT deep rooting crops be they forage or cash. High inputs just stoke the fires in the soil and get the wrong fauna going. Some soils take abuse much better than others and can take more of the high input system but most will decline to a resting level of about 2%.
If you think that everything above the soil is worm food and everything below soil food i dont think you can go wrong.

I agree that cropping burns OM but it should be possible to achieve a system that adds it quicker than it is burned. I am confident the steps I am taking will do this, the thing I am unsure about is how quickly it will build.
What deep rooting low input cash crops can you recommend?
 

IEM

Member
Location
Essex
soil carbon levels will be affected by biological variations in sequences (not ratios ) which is also variable zonally and if out of kilter cause depletion , applying Pas 100 compost can actually exasabate a problem rather than solving it, while in peat bogs biology can self regulate and minimise carbon degredation .

Do you mean a soil which has only been in arable crops for 85 years with chopped straw the only OM addition could have its OM level lowered by applying the wrong type of compost?
 

IEM

Member
Location
Essex
IEM, On first reading the OP I thought you were wanting to increase the OM with a view to it eventually being available to your crops. I then wondered whether your aim is to sequestrate carbon in the soil that will not break down for a very long time. One of the things that made me wonder this is the use of heat treated compost so that as Clive posted at #20, it is carbon without the benefits of natural vegetationthat is composted without heat - a type of biochar in fact.

What is your aim, plant food or carbon sequestration?

My aim us to increase soil organic matter to increase plant available nutrients, water holding capacity and infiltration, soil microbial and earthworm activity etc etc.
I hadn't thought of the compost as like biochar but it will only have about 2% available N which indicates it will break down very slowly. I think as part of a mix of methods it will help me get where I want to be. What do you see as the pros/cons of heat treated?
 
I have previously read some of Robert Elliot's book (found it a bit heavy going but will give it another go). Currently reading Fertility Farming by Newman Turner, similar system and a great read with a lot of relevance today.
He was a big believer in compost although I'm not sure what he would think to the green waste compost I am importing! I am applying compost during the cropping part of the rotation not to the ley as I feel this is the most beneficial time to do it. Newman Turner however applied some compost in the 3rd year of his 4 year leys as well as a larger amount in the cropping phase.

I thoroughly recommend perservering with Elliott. I also have extremely high regard for Turner. I think I have read everything he published in book form. The other books are worth reading too, although I consider Fertility Farming his best. Obviously I have not read all Turner's writings, especially that in magazines such as The Gardener and The Farmer. Other people involved in these magazines such as Lawrence Hills (probably my all-time hero of soil fertility - I have his originally identified Bocking 4 comfrey obtained more than 20 years ago from HDRA) and Sewelll-Cooper (I have a copy of his original gardening book somewhere - probably with my sister in the UK) were also people whose views should be taken into account by anyone seriosuly interested in soil fertility.

You will note that Turner could not produce as much compost as he felt he needed.

I am sure Turner would approve of you importing nutrients, after all he did say "every time you sent a vehicle into town it should return with sewage sludge, sawdust (these two were the main components of his compost heaps) wood shavings, vegetable waste from greengrocers, or even old hessian sacks," - another quote from my own writing. Sir Albert Howard's Indore compost also relied on importing nutrients from other people's land.

Neither of these mehtods is of course sustainable on a global scale, but since almost nobody is practising these systems, I think you should go along with it as long as you can.

I am inclined to go along with Elliott and use manures and compost only during the cropping phase. A personal opinion. I would never attempt to tell anyone how they should farm their own land. I make suggestions, perhaps even some times when they are not requested, but nobody should ever tell someone else that they must, or even should, do anything in particular with their own land.
 
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My aim us to increase soil organic matter to increase plant available nutrients, water holding capacity and infiltration, soil microbial and earthworm activity etc etc.
I hadn't thought of the compost as like biochar but it will only have about 2% available N which indicates it will break down very slowly. I think as part of a mix of methods it will help me get where I want to be. What do you see as the pros/cons of heat treated?

My sentiments exactly. If we grow two blades of grass where only one grew before........ it is up to our succesors in tenure to continue our work and nothing we can do if they do not. I believe that if we increase degradable soil OM then all else in your first paragraph automatically follows.

I do not have the scientific knowledge to discuss the pros and cons of heat treated compost, but just saw it from a practical point of view as being of low degradability and therefore of little practical use as a fertilty builder in the foreseeable future of an individual farmer. I am a great believer in building soil OM that can be broken down within a reasonable time to become available to plants. Off topic, but I do not see why farmers should sequestrate carbon in their soils that is of no short or even medium term benefit to them when the rest of the world is producing the carbon we are being asked to sequestrate.

I am quite happy to have crop residues etc scattered on the surface after preparations for a subsequent crop as I know these will eventually become part of the food chain for the underground army, but I am not too happy about having to produce OM that I know cannot be utilised by me or my successors within the next 20 years. It takes far too much N to break it down into useable form, and that N either depletes my underground forces, or my crops during that time. Humus has a ratio of approx 10C:1N and if there is too much C then it takes too long to make it available to crops.

2%N in compost means that the C is sequestered unless a lot of N can be applied to break down the C. Of course, this is what some people want. They do not want farmers to break down the C into useable forms. They want it to stay sequestered so that the rest of the world can continue to produce C that we will sequester in order that they can continue to produce even more C with equanimity.
 
I agree that cropping burns OM but it should be possible to achieve a system that adds it quicker than it is burned. I am confident the steps I am taking will do this, the thing I am unsure about is how quickly it will build.
What deep rooting low input cash crops can you recommend?

Cannot be too specific but if you look at ancient examples of crop plants they had huge root mass to scavenge effectively. Modern crossed have had this trait removed as they are almost hydroponic in their cultivation with all the inputs. This is where the disjoint occurs. Modern cropping cannot maintain the organic matter in the soil without importing some and this is only a sticking plaster as it is burned so quickly. A long term ley followed by notill may be the best answer unless you can grow some heritage crops but the trick is making money from them.
 
My sentiments exactly. If we grow two blades of grass where only one grew before........ it is up to our succesors in tenure to continue our work and nothing we can do if they do not. I believe that if we increase degradable soil OM then all else in your first paragraph automatically follows.

I do not have the scientific knowledge to discuss the pros and cons of heat treated compost, but just saw it from a practical point of view as being of low degradability and therefore of little practical use as a fertilty builder in the foreseeable future of an individual farmer. I am a great believer in building soil OM that can be broken down within a reasonable time to become available to plants. Off topic, but I do not see why farmers should sequestrate carbon in their soils that is of no short or even medium term benefit to them when the rest of the world is producing the carbon we are being asked to sequestrate.

I am quite happy to have crop residues etc scattered on the surface after preparations for a subsequent crop as I know these will eventually become part of the food chain for the underground army, but I am not too happy about having to produce OM that I know cannot be utilised by me or my successors within the next 20 years. It takes far too much N to break it down into useable form, and that N either depletes my underground forces, or my crops during that time. Humus has a ratio of approx 10C:1N and if there is too much C then it takes too long to make it available to crops.

2%N in compost means that the C is sequestered unless a lot of N can be applied to break down the C. Of course, this is what some people want. They do not want farmers to break down the C into useable forms. They want it to stay sequestered so that the rest of the world can continue to produce C that we will sequester in order that they can continue to produce even more C with equanimity.
If the om in the soil has a high carbon content and does not break down quickly, surely it will impart a lot good properties to the soil. For example water holding capacity, infiltration, increase cec and generally improve soil structure. I think whether it is burnt off feeding the crop or stays in the soil it is how it improves the soil health that should benefit crops most.
 
Modern crossed have had this trait removed as they are almost hydroponic in their cultivation with all the inputs. This is where the disjoint occurs. Modern cropping cannot maintain the organic matter in the soil without importing some and this is only a sticking plaster as it is burned so quickly

Not looking for an argument, but would you care to elaborate on these statements, and preferably provide some research links to back up that in bold? My experience, with regular soil tests, shows otherwise, but of course, my experience may be totally contrary to the wider reality.
 
If the om in the soil has a high carbon content and does not break down quickly, surely it will impart a lot good properties to the soil. For example water holding capacity, infiltration, increase cec and generally improve soil structure. I think whether it is burnt off feeding the crop or stays in the soil it is how it improves the soil health that should benefit crops most.

Does inert carbon "impart a lot of good properties to the soil" that organic matter which breaks down into plant available nutrients relatively soon does not?

Animal and vegetable matter incorporated into the soil, either by cultivation or worms etc., and which does break down, does everything you say in your second sentence.

I do not like the expression "burnt off" which appear to have become prevalent in very recent times. OM is not burnt, it is broken down by what I refer to as "the underground army" and becomes available to plants.

Adding carbon through charcoal and biochar to sequester carbon is not the same as adding OM with the purpose of it feeding subsequent crops in the next few years. No reason why anyone should not do both if they so wish, but they serve two different purposes. That which is used up needs to be replenished on a regular basis, the other does not.
 
Not looking for an argument, but would you care to elaborate on these statements, and preferably provide some research links to back up that in bold? My experience, with regular soil tests, shows otherwise, but of course, my experience may be totally contrary to the wider reality.

I used a generalisation to which there are always differences but in a once typical two wheats one rape with ploughing the soil on will fall to the resting value of that soil. Ploughing up a long term ley would see a decline and OK you can add as much o m as you want but without the action of deep healthy roots and the associated soil fauna it is just that an addition not incorporated into the soil in a proper manner.
Muck is not o m as such but soil o m precursor.
Maybe your rotation/soils cope well with shallower roots but here I have found that I can add what I want but it is only cosmetic compared to a grass ley.
 
Mikep, I completely agree that any form of continuous cropping will deplete soil OM - unless (and this where we disagree) a lot of FYM is applied to the soil. My father had a smallholding that was permanently cropped, but we also had prodigious quantities of FYM from pigs and poultry. I do not have the records now (I think I lost them in Australia) but the soil OM was high through yearly heavy applications of FYM. FYM is OM. It may not be in a form available to the plants, but it is OM, and any picked up in soil samples will be included in the %age of OM in the results. It will in time become available to the plants. If you say otherwise, then what do you consider to be OM?

My experience is not limited to this farm, or even this country, hence my request for research to show that what I have experienced does not always follow.

From your last line, I think we are agreeing on the best way of increasing OM. My whole point in posting originally was to suggest to IEM that he might read Elliott's book and perhaps be persuaded to follow the idea of a 4 years' ley followed by 4 years' cropping. On a mixed farm, that is my preferred system. I only have two small fields that are not in olives or almonds, so cannot use the system here.

The only record I have seen of someone following Elliott for a long time is a book by William Lamin "Thirty Years farming on the Clifton Park system". Well worth reading, as well as Elliott, and is also available online.
 
I am still working on my understanding on of soils. I get a bit confused by statements like OM being used up by crops.
My understanding is that soil is made up of minerals, water, air and anything carbon based is organic matter. OM is anything from undecayed crop residue to an earth worm and everything in between. The ways I see "carbon" getting into the soil are from 1)decaying plant residue and roots, 2) root exudates that the plant produces to "feed" soil microbes for its benefit 3) from what farmers add. There is a soil food web using this OM as the primary food source, some of the carbon is "burnt" off as carbon dixoide by the microbial activity. But more complex forms and stable forms are produced and nutrients are released for plants to use by this. There was a great digram I saw at an Elaine Igrams talk of bacteria having more nitrogen than protozoa so that when protozoa ate bacteria they excreted the excess nitrogen which plants ( or bacteria ) could use.
I see humus as the end product of the soil food web, but I don't really understand what is.
Are soils with high OM healthy because of the soil microbes they support or due to the nutrients being released from the OM. If soils have limited soil microbes, for example a lot of intensive farmed soils are meant to be bacterial dominated so do they just burn off the carbon from the OM without alot of other benefits.
Although biochar adds carbon to soil and i think it is meant to be a good home for soil microbes, I don't see it as complex carbon source that can be food for microbes so is it really OM.
My understanding could be wrong and I would happy for where I have gone wrong to be pointed out.
 

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