Depleted Soil


"The destruction of soil is the most fundamental kind of economic loss which the human race can suffer." - Aldo Leopold, 1887 - 1948

"Humanity loses another 0.3% of our global food production capacity each year to soil erosion and degradation." (that's 30% in 100 years!) - UN Global State of the Soil Assessment, 2015

There are more living organisms in a teaspoon of healthy soil than there are people on the planet, combine that with the organic matter and healthy soil is literally teaming with carbon. Sadly most of our soil is not healthy, Industrial agricultural management practises have damaged our soils to the point where 50-75% of the organic matter has been lost in the last 100 years. Consequently it's not surprising to learn that agriculture is responsible for more legacy carbon in the atmosphere than fossil fuels. And lost soil carbon goes hand in hand with soil erosion - "Globally, 75 billion tonnes of soil are lost from arable land each year and an estimated $400 billion in agricultural production is lost." (Food and Agriculture Organization of the United Nations)

Tilling, chemicals, monoculture and continuous grazing have resulted in soils with:

  • Poor soil microbiology
  • Poor structure
  • Broken mineral and water cycles
  • Nutrient deficiencies

All of which result in nutrient poor food

Mineral depletion in Vegetables (1940 - 1991) Average of 27 kinds of vegetables:

  • Copper - declined by 76%
  • Calcium - declined by 46%
  • Iron - declined by 27%
  • Magnesium - declined by 24%
  • Potassium - declined by 16%

Mineral depletion in meat (1940 - 1991)

  • Copper - declined by 24%
  • Calcium - declined by 41
  • Iron - declined by 54%
  • Magnesium - declined by 10%
  • Potassium - declined by 16%
  • Phosphors - declined by 28%

Source: Thomas, D.E (2003). A study of the mineral depletion of foods available to us as a nation over the period 1940 - 1991. Nutrition and Health, 17: 85 - 115.

"The true problem is that we don't have enough carbon in our soils." - Dr. Kris Nichols

"We have this idea that plants take form the soil. Nothing can be further from the truth." - Dr Christine Jones

Regenerative Agriculture enhances the functioning of the soil's core ecosystem cycles - energy, water or mineral - by getting carbon in the ground and enhancing soil biological function. Gabe Brown is one of regenerative agriculture's legendary pioneers on his farm in North Dakota. He published a book on his experiences on the road to Regenerative Agriculture called Dirt to Soil. It starts with the following statement, "Our lives depend on soil. This knowledge is so ingrained in me now that its hard for me to believe how many soil-destroying practices I followed when I first started farming." If you are not improving your soils you will leave behind less than you found and you are not farming, you are mining.

In it he lists the principles of building and maintaining soil health.

Regenerative Agriculture's five principles for soil health

1. Limited Disturbance

  • Mechanical and Chemical
    • Tillage destroys soil structure and kills microbes, specifically mycorrhizal fungi (tilled soil erodes at 20 times the speed of no-till soil)
    • Chemicals - fertiliser, herbicides and pesticides kill soil biology

2. Armour

  • Always keep your soils covered
    • Crop residue
    • Cover Crops
    • Trampling

3. Diversity

  • Strive for diversity in both plant and animal species

4. Living Roots

  • Maintain a living root system in the soil for as many days of the year as you can
    • Without photosynthesis there are no root exudates to feed soil biology

5. Integrate animals

  • Nature does not function without animals
  • Grazing stimulates plant to put more carbon in the soil feeding the soil biology and urine, dung and saliva stimulate that biology, taking productivity to a new level

"I used to wake up in the morning thinking about what I'm going to kill today: a fungus, a weed, a pest. I was going to kill something. Now I wake up thinking how I'm going to get more life on my operation. It's a lot funner working with life than with death." Gabe Brown

"In healthy, living soil covered with green plants for much of the year, the carbon supply for beneficial soil microbes can nearly be endless." - Gabe Brown


Video: Gabe Brown explains his 5 Principles of Regenerative Agriculture


Video: Soil Health Principles - Ray Archuleta

Why we need to wean ourselves off Nitrogen

"I have sinned against the wisdom of the Creator and, justly, I have been punished. I wanted to improve his work because, in my blindness, I believed that a link in the astonishing chain of laws that govern and constantly renew life on the surface of the Earth had been forgotten." - Justus von Liebig - the "father of fertiliser"

The addition of synthetic nitrogen to soil causes the soil microbes to go into overdrive, organic matter is lost and carbon is released from the soil into the atmosphere. Secondly the readily available nitrogen means the plants and soil microbes use the nitrogen independently of each other rather than creating their crucial symbiotic association. What this means is when the time comes for the plant to get other crucial nutrients and microbe metabolites from the soil the pathway isn't there and the metabolites haven't been produced.

Synthetic fertilisers disrupt the symbiotic relationship between plants and soil microbes, destroying the nitrogen cycle, the phosphorous cycle, the carbon cycle and the cycles of numerous other nutrients plants need to be healthy, all of which means nutrient poor plants. If we attend to the needs of the soil, and the ecological cycles will begin to get back into sync.

"There is a direct connection between soil health and crop health." - David Montgomery

Industrial agriculture relies heavily on synthetic nitrogen to overcome its multiple, increasing deficiencies (11 million tons in 1960 to 115 million tons in 2017). As the soil is depleted year after year more nitrogen is required and that nitrogen is becoming less and less effective. (In 1960 each ton of chemical fertilizer resulted in an increase in grain yield of 75 tons, in 1990 this resulted in just 25 tons). Only 30-50% of the nitrogen is used by the plant. Most of the nitrogen that is added to the soil is lost - wasted through denitrification, leaking, erosion and volatilization of ammonia.

"If nothing is changed in our agricultural system, why are we using two to three times as much fertilizer to accomplish the same thing?"  - Willie Durham, NRCS soil health specialist 

"In 1960, more than half of the N came from the soil from microbial processes. Those microbe populations declined over time because they didn't get fed, so they weren't available to do the job and efficiency has declined. We need to regenerate our soils to solve this issue."  -  Kris Nichols, Microbiologist

Although lost is the incorrect word as it is not lost but rather ends up as pollution in the atmosphere, waterways and the sea. Greenhouse gas emissions from nitrogen fertilizers are around 3% of global emissions (about the same as the aviation industry) and runoff of nitrogen to the sea is responsible dead zones all around the world, most infamously at the mouth of the Mississippi.

Nitrogen fertilizer production is the single biggest cause of greenhouse gas emissions in agriculture. In the production process natural gas is used, so much natural gas that nitrogen fertilizer is today the single biggest user of natural gas. Coupled with this is the increase in methane emissions caused by leaks from the fracking industry which have caused atmospheric methane to rise rapidly. This emission is not even included in fertilzer life cycle calculations.  

By transitioning to Regenerative Agriculture farmers are able to reignite the microbiology in their soils and reduce their and the world's growing dependency on synthetic nitrogen, reducing the pollution footprint of our food while producing nutrient dense plants. As David Montgomery says "This is not a question of the environment vs the economy, it a win, win." because with the soil biology healthy again and being fed by cover crop rotations the yields are as good as their synthetic fertiliser using neighbours.

"Chemical fertilizers are not (yet) essential for feeding the world or for human survival, but they are essential for the global model of commercial agricultural production." - Gunnar Rundgren

"Upon this handful of soil our survival depends. Husband it and it will grow our food, our fuel, and our shelter and surround us with beauty. Abuse it and soil will collapse and die, taking humanity with it." - Sanskrit proverb 1500 BC

Video: Cover Crops 

Video:  Soil Health Institute

Degenerative Farming

The reductive approach employed by Industrial Agriculture has reduced the analysis of soil to chemical boxes.  Soil tests should be biological and chemical not just chemical for instance the Haney Test which is designed to mimic nature's approach to soil nutrient availability.  By not taking a holistic view of soil and its natural functioning "75 billion tonnes of soil are lost from arable land each year".  Every major civilisation before our current one has destroyed itself my destroying its soil and we are gaily following suit.  

Regenerative Agriculture protects soil and its invaluable organic matter.  By not ploughing soil and keeping it covered wind doesn't blow it away, rain drop impact doesn't break it up and that precious rain water infiltrates into the soil rather than flowing away with it.  These images from Kiss the Ground show the destructive force of our current farming paradigm.