The Importance of Recycling Energy, Part 2: How to sequester carbon in the soil

This is a continuation of Part 1 in the September Jehovah-Jireh Farm Newsletter on the importance of recycling energy.

Note: Using organic farming methods to sequester carbon in the soil is an important subject that was presented to our government officials several weeks ago. Since I wrote part one, I found out that Mark Smallwood, the director of Rodale Institute, walked from Rodale Institute in Pennsylvania to Washington D.C. to hand deliver a White Paper detailing research proving that regenerative organic agriculture can absorb carbon from the atmosphere and reverse climate change. The White Paper is titled: Regenerative Organic Agriculture and Climate Change, A down-to-earth solution to global warming. The full text of the White Paper can be found at: http://rodaleinstitute.org/regenerative-organic-agriculture-and-climate-change/
Incidentally, Mark Smallwood used to work for MOM’S Organic Market in their main office in Rockville, MD. and also helped us one time to process chickens at our old farm.

 

We today have an important opportunity to make a significant step forward to sequester carbon, build topsoil, control erosion, and feed the world through organic farming. There are many that are greatly concerned that we have irreparably harmed the environment, are destroying life, and leaving future generations with an environmental mess because our excessive use of fossil fuels. Many feel hopeless and that too many people do not care what they are doing to the environment.

There is hope!

Plants to a large extent were the original source of our present day fossil fuels. Plants are also a key element in recycling energy and putting the CO2 gasses back into the soil where they belong.

There are a number of ways to sequester carbon in the soil. What I want to share with you is a simple, easy method that we have used here at Jehovah-Jireh Farm.

In the first seven years here on this farm we have sequestered approximately 325,570 lbs of Soil Organic Carbon on 35 acres. That represents recycling as much CO2 as the yearly output from approximately 146 cars. That was accomplished by increasing the soil organic matter on most of the farmland by almost one percentage point. That is without spreading organic matter or fertilizers other than lime. The only manure was the droppings from chickens when they are on the pasture and from the sheep and cows while they are grazing. The amount of  carbon sequestered is according to soil tests that were taken at the end of 2013. It represents the carbon sequestered in the top six inches of soil, although there has been much more carbon than that sequestered at greater depths in the soil. 

The method that we used to sequester the carbon was letting the grass grow a foot or more tall and then grazing or mowing the grass and letting it decompose into the soil. This is a method that we discovered as we mowed the grass in the American chestnut orchard located here on the farm and observed the significant increased growth of the grass and the increased growth, vigor, health, and blight resistance of the American chestnut trees. Mowing pasture grasses is one of the best, the easiest, and cheapest of fertilizers.

Grasses often have more root mass and depth than the mass and height of grass above the ground. When the grass is mowed from a height of 24″ down to 4″, the roots slough off to correspond to the amount of grass left above the surface. As these roots that sloughed off decompose, they build organic matter in the soil to the depth the roots had been. It is not just the organic matter on the surface of the ground from the mowed grass that contributes to the organic matter of the soil.

Pasture based farming, using rotational grazing and managed mowing, is an important method of sequestering carbon in the soil in a very stable manner. Rodale Institute has proved that the proper organic crop growing methods are also an important carbon sequestering method. It is my opinion from my observations and research that pastures can sequester carbon faster, easier, to a greater depth, and have it more stable in the soil than can be accomplished with organic crop farming methods. That does not mean that sequestering carbon by organic crop farming methods is unimportant; it is important. But what it means is that globally we can sequester much more carbon by raising animals on pasture in pasture based systems rather than growing grain and feeding the animals grain in confinement operations. Plus, the grass-fed meats with higher omega-3 fatty acids are much more healthy for the consumer.  

Typical response of grasses to grazing. Above ground growth is more lateral and roots “die back” to match needs of above ground biomass. Diagram C. Luke 2011 http://www.sonoma.edu/preserves/prairie/management/restoration.shtml

 


http://kansasgraziers.blogspot.com/2013_10_01_archive.html
Up to 90% of a plant’s mass is in its root system. What is below the soil is much more important for sequestering carbon than what is above the soil. The plant on the far right has much more root mass than the mass that is in the grass above the soil level. The grass clump on the far left sloughed off most of its roots when it was cut short. The roots can then decompose and build carbon deep in the soil where it will be stable and stay in the soil for a very long time.

The above illustrations show the importance of managing plant roots by grazing and mowing to build carbon in the soil. The roots below the soil are more important for sequestering carbon than the grasses above the soil. This is significant, because it allows us to utilize the grass for feeding livestock and producing an income from the land while at the same time using the roots to sequester carbon deep in the soil, making the soil more drought resistant, reducing rain run off and erosion, and making the soil more fertile.

The depth that carbon is sequestered in the soil is important. Carbon that is greater than 12″ deep (30cm) is very stable in the soil. The Rodale Institute’s White Paper points out the importance of depth in the sequestering of carbon:
“It is likely that current data sets underestimate soil organic carbon stocks in organically managed systems because soil carbon is often measured at plow depth when recent findings suggest that more than half of the soil organic carbon stocks are likely in the 20-80cm depth. Beyond 30cm in the soil profile, the age of carbon increases continuously, much of it persisting for thousands of years.  How carbon acts in this subsoil range is poorly understood, but increasing rooting depth, application of irrigated compost (compost tea), choosing deep rooted grass-legume cover crops and encouraging earthworm abundance are all promising pathways for introducing carbon to depths where it is likely to remain stable over long periods.” (p. 10)

To get the greatest depth of roots in the soil, it is important that grasses be allowed to grow at least a foot or two in height before grazing or mowing. Grasses in home lawns will not be able to contribute much to carbon sequestering because they are never allowed to grow very tall.

One more plus to mowing pastures in addition to sequestering carbon is that it creates a beautiful manicured farm landscape. Beautiful pastoral farm landscapes do a soul good like a medicine. We need to create more beauty around us.
Our charcoal/biochar kiln experiment at Jehovah-Jireh Farm.

In 2009 we experimented with making charcoal to sequester carbon and to build up our soils. Inside this charcoal kiln were five metal 55 gallon barrels filled with split firewood. We made six batches of charcoal to use in the garden and in the chicken bedding. Making charcoal/biochar is labor intensive. In half of our garden, we applied about an inch and a half of charcoal and incorporated it in the top six inches of soil in a three foot wide by 70 feet strip perpendicular across the various rows of vegetables . Unfortunately, we did not see any improvement in growth, drought resistance, or brix improvement to the plants grown in the charcoal enriched soil in any of the years since then. Five years later, there is no noticeable difference in the color of the soil where the charcoal was applied.

Our experiment with biochar was not successful. It does not mean that charcoal/biochar is an ineffective method of sequestering carbon in the soil. The Terra Preta soils in South America show otherwise. Charcoal/biochar is a method that needs more research. 

There is much more to learn about how to sequester carbon and to build topsoil using atmospheric carbon. We want to experiment with increasing the brix (sugar content) of our pasture grasses. By increasing the photosynthesis of the plant leaves, the sugar (and carbon) content of the plant can be increased. The plant sends these sugars to the roots to feed the roots and microbes in the soil. By increasing the sugars in the plant, we should be able to significantly increase the carbon sequestration in the soil.

There is much more that we would like to experiment with to improve the soil. We thank you for your support of our farm in buying our farm products. Your support is what enables us to do these experiments in our living laboratory (the farm).

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