Current and emerging methodologies for estimating carbon sequestration in agricultural soils: A review

https://krishi.icar.gov.in/jspui/bitstream/123456789/31924/1/Current%20and%20emerging%20methodologies_STOTEN_AKN.pdf

Spectroscopic techniques may measure soil carbon sequestration like that of Soil Organic Carbon stocks in laboratory and in-situ even up to a deeper depth.

Test for percentage of SOM or Soil Organic Matter -- The most common method used to estimate the amount of organic matter present in a soil sample is by measuring the weight lost by an oven-dried (105°C) soil sample when it is heated to 400°C; this is known as 'loss on ignition', essentially the organic matter is burnt off. Only $16 from the Waypoint Lab in Anaheim, California from a one quart sample.

See https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9251.pdf

Then to measure the year-to-year sequestration, need to retest from the same spot and see what the annual increase is.

Another very interesting test to do, is radiocarbon date that organic matter from different depths, so you can see when the carbon is sequestered by various kinds of plants, how long is it stored? Last year, testing desert native grass soil from Nevada, it was at least 300 years. Costs about $400 per test.

I maintain that the most serious danger now facing human society is the rapidly increasing destabilization of the Earth’s meteorological and oceanographic systems.

It’s apparent that a more definitive definition of the term “humus” is now necessary in our battle against global warming.

Converting atmospheric carbon dioxide into humus in the soil is now an imperative. If a slightly more specific meaning for the word “humus” is part of the solution then it’s wise and certainly more definitive to simply and more clearly re-define what we want the word “humus” to define.

It will also, undoubtedly then be exactly what most of us have already understood humus to be, and have for decades.

Just clarifying the meaning and then “We won’t be throwing the baby out with the bath-water.”

I was invited to the US in 1989 to participate in a twenty person “Think Tank” to “Define the Future of Sustainable Agriculture in the United States for the Following 25 Years”. It was held at the Esalen Institute. Big Sur, CA. in January 1990.

I accepted the invitation.

I argued, my then recently conceived concept, that the removal of our atmosphere’s carbon dioxide overload could only be achieved, both practically and economically by increasing the fertility of the world’s agricultural soils. From there the idea spread gradually around the world.

Fertility enhancement to a depth exceeding one third of a metre (approximately 12 inches), is undoubtedly the most easily monitored and practical system now available. In truth, with a good eye and a pick and shovel it’s been in general use for generations of our world’s farmers.

Removing carbon dioxide from the atmosphere is most conveniently achieved by “increases in the quantities of soil humic substances in the soil”. The word “Humus”, seems the wisest and most practical term to define those substances. And to many that is exactly what it already does mean.

Being specific, the composition of humus can be predominantly defined as being, humic acid, fulvic acid, ulmic acid and humin, and smaller quantities of materials of similar molecular structures and formation histories. They all have molecular structures capable of resisting their own molecular breakdown, and can do so for centuries.

Those humus molecules must also be molecules capable of being regularly formed in all soils, and additionally, formed in periods of way less than a decade. Humus can actually form in weeks, and last for millennia.

Humus is a remarkable substance and humus content in the past effectively delineated sub-soils from the commonly more fertile topsoils.

In the slightly more specific definition of “humus” we have adopted, we nominate that the material must always easily pass through a 2 mm aperture screen. Fibrous materials are not yet humus and are automatically excluded as it can generally be assumed that such fibrous material would always have great difficulty in passing through a 2 mm screen, and therefore can safely be ignored.

Currently the concept is being promoted by some unfriendly parties that lignite can be considered as a component of humus. That is simply ridiculous. “Brown coal” is another name for lignite. Black coal is fossilized forests. Lignite is fossilized peat. Peat is not humus and neither is lignite. They are quite different. I suspect that somebody is obviously interested in generating confusion.

The clarification of the meaning of the word “humus” is primarily designed to allow us to conveniently determine changes in the carbon content of soil, on typically an annual basis, so we can pay our farmers for clearing the excess carbon dioxide out of our air.

It must always be remembered that the fundamental objective and imperative is that removal.

We use a “surface area concept”. A soil sample is “what’s under that specific area”.

Additionally, absolute values of carbon content become totally irrelevant. We measure the exact quantity of CO2 removed as only changes are of significance.

The ultimate objective must always be removing the carbon dioxide overload from the air. And do it as quickly and as economically as is humanly possible and we can do it currently and easily for less than $15 US a tonne, carbon dioxide equivalent.

In the methodology we recommend: *** LOI is always to be used. *** Individual sample weights are to exceed 250 grams *** For accuracy and consistency samples are always to be weighed at temperatures between 1000 C and 1400C. *** Changes in the soil humus levels, are to be always corrected using local area derived calibration graphs.

Measuring changes in humus levels and allowing a fixed 58% humus carbon content gives us an accurate and consistent system for calculating what we should pay our farmers.

We simply pay our farmers, our graziers, our ranchers, for removing the carbon dioxide overload from the atmosphere and in doing so, everting an otherwise horrific outcome for all our human societies.

“Humus” is a beautiful word. It should never be abandoned. It should in fact be protected. Protected from being contaminated by thrusting upon it a burden of false meanings. False meanings, that those who actually farm and manage our agricultural soils know to be so very wrong.

Humus must stay the beautiful word it still is.

Here in Australia, we know how to rapidly build humus in agricultural soils. We make the equipment.

We know how to create a soil sample location system so the farmer (with an observer) can easily locate each sample location point using only the GPS in their mobile phone. We designed it.

We know how to easily, accurately and inexpensively collect to a metre down, the infield soil samples. The farmer (with their observer) can do that. We make the sampling auger.

We know how to test individual soil samples weighing up to 2 kilograms. It uses a Loss On Ignition test principal. It’s called a “Carbon Still”. We make this test unit

We know exactly how the payment system should operate and be monitored.

It can be private initially but rapidly must become State funded.

We know how to weigh individual soil samples with all weighings conducted at temperatures between 1000 C. and 1400 C. Also all weighings can be done without removing the soil sample from the Carbon Still. The accuracy is always within one gram per thousand.

We make the equipment.

But --- We don’t know how to combat the massively funded and incredibly astute marketing operations of the world’s fossil fuels - agrichemical industries.

Allan Yeomans

Australia

You can consult this recent report under green India Mission