by Blain Hjertaas
Not the average topic of conversation for most people. Yet it’s critical to all of our survival. 2015 is the International Year of Soil as declared by the UN. 99.7% of what we eat each day comes directly from the soil. Over the eons of time mankind has abused it badly in some cases causing civilizations to collapse. Agriculture has traditionally destroyed and then moved on. Unfortunately there is nowhere else to go.
The production of food causes a soil loss of 4 tons of soil per person per year on an annual basis. There are 7 billion of us so that equated to 28 billion tons of soil loss annually from our agricultural areas. Clearly not sustainable. Add to this the loss from urbanization and population increase and something will have to give soon with disastrous consequences. Throw in climate change and it doesn’t bode well.
I don’t believe it’s a bad news story. We know how to fix this. It’s simple and a win-win for all. It all has to do with carbon. We have put our carbon in the atmosphere instead of in the soil. We have lost most of our organic matter or carbon or humus over the last 130 years of farming. The 1930’s took their toll, the summer fallow era took more and each time tillage is performed more carbon is oxidized and goes into the atmosphere. Add to this the carbon released from fossil fuel burning and we have an increase from a historical levels of 300PPM to 400PPM of carbon dioxide in a 50 year period. This is a huge increase in a very short period of time and we are just beginning to understand the ramifications. At this point in our history there is no indication of slowing our rapid increase.
It would seem prudent to me that we should take carbon back out of the atmosphere and put it into the soil where it can do good. The process is simple. Photosynthesis does it free for us ever day if we have green leaves working for us. The plant takes oxygen and carbon dioxide from the air and makes simple sugar or glucose. This is transported to the roots where 20-30% exudes from the roots into the rhizosphere to feed the fungi and bacteria. This is a symbiotic relationship between plants and bugs. They get sugar from the plant and in return they can make unavailable nutrients available to the plant. They build structure in the soil and as death occurs the plant and animal remains are converted into more complex forms of carbon or humus. The more humus we have the more soil microbes there are, the more water holding capacity the soil has, the more nutrient dense the food that is produced will become and the higher the overall yield will be. This keeps getting better and the energy source is solar energy converted by green leaves. Sounds like a pretty good thing. Our modern agriculture is destroying or holding at the current levels because of the negative effects of tillage and pesticides especially fungicides.
Several years ago a group of farmers were concerned about this issue and decided to prove whether this trend could be reversed or be regenerative and begin to build. The soil carbon coalition was formed to monitor soil carbon levels across North America’s farmland.
Plots were established and initial samples were analyzed in 2011. In the fall of 2014 these same sites were again visited and analyzed for carbon. The results are very impressive with all farms showing positive increases in three years. In tonnage the seven farms tested in SE Sask. had 4627 hectares between them and sequestered the equivalent of 131 370 tonnes tonnes of carbon dioxide. The average Canadian has a carbon footprint of 18.9 tonnes. Therefore each hectare negated the effect of 1.5 persons or these 7 farms had a zero carbon footprint for 6973 people.
All of these farms practice high stock density grazing with long recovery periods. It proves conclusively that cows are carbon negative as this wouldn’t have happened if cattle had not been improving the soil on these farms. Cattle ensure the litter on the ground is pushed tight so that decomposition can occur. The act of grazing stimulates the growth of grass making more solar capture possible. We need biology working on our farms to make this happen. Livestock enhance biology.
This is a great news story. All of these farms have had increases in grass production, had a decrease in inputs, are holding more water in the soil and producing more nutrient dense food. Clearly farmers are more profitable, consumers have better food and society has more water holding capacity mitigating floods and mitigating climate change. To view results check out the web site at http://www.soilcarboncoalition.org