"A nation that destroys its soil, destroys itself."

President Franklin D. Roosevelt, 26 February 1937.

Eighty-nine years later and the world is furiously chasing GHG emissions to reduce impact, while ignoring the true source of the heat – the destruction of the soil and its vegetative cover.

Desertification, increased heat and erratic rainfall is not primarily caused by GHG but the destruction of the soil cover and the glue that holds soil together. Fertilisers, herbicides, pesticides and fungicides are destroying the glue that aggregates soil and the biome that makes the glue. Farmers are hurting, both financially and their wellbeing,  by the costs of these chemicals and their application.  Throughout the world, we have been destroying our soil.

Countries on fragile soils have dehydrated their landscape more quickly than the USA and Europe, where the most resilient soils occur.  In the countries with fragile soils, farmers and rural communities have been forced to look for solutions that work within their landscape.

But now, even in the world’s great food baskets of USA and Europe, the de-aggregation of soil is impacting both climate and landscape hydration.

The fabric of American rural society is becoming unstuck as farm families are placed under huge pressure.  Farm owners and farm families are not used to the increased propensity of unreliable rainfall and drought (like the Australian Farmer) and they are not financially prepared for the variability. Loss of food security and rural community harmony decaying the foundations of Nations is as relevant today as it was in 1937.

While the knowledge of adverse externalities was limited to dust storms in 1937, we now know the entire climate and landscape hydraulic system is impacted by how we manage rural landscapes.

The Sponge

Maximal aggregated soil has maximum efficacy for plant available water while creating minimal runoff. This is known as having an efficient sponge. High infiltration with high storage capacity in soil and alluvium means lower, less intense floods and prolonged water flow into summer (baseline flow).

A sponge (aggregation) can be grown, and a sponge can be thickened.

It is often cited that it takes 1000 years to grow an inch of soil. This is the weathering rate of rock and by growing soil from the bottom up.

But over 150 years ago, Charles Darwin lead the way in regeneration in his preferred authored book on earthworms, when he observed that the soil can be built from the top down reasonable quickly by living processes.

Yes, a sponge can be thickened quite quickly.

Our team have observed the A horizon (top soil) being extended from 50 mm to 800 mm in 8 years of regenerative farming and plant available water from 150 t/ha to over 2500 t/ha.

A drought is not the rainfall received but the duration of time before prolonged permanent wilting point or dehydration of the landscape occurs. This is dependent on the water already stored in the landscape. The amount of water in a hydrated landscape controls about half the rain locally – this is known as the small water cycle. A dehydrated landscape with minimal PAW (150t/ha) compared to 2500 t/ha with tree belts causes a difference of rainfall deficiency, potentially leading to a drought every 2 years, compared to a potential drought every 20+ years. This indirectly supports what Dr Allan Savroy stated “…droughts doesn’t make bare ground. Bare ground makes droughts.”  Disaggregated soil causes bare ground.

Square Clouds and Talking Trees

Our team, including farmers, have observed that increased plant diversification, both pasture and trees promtes a more diverse soil biome, which in turn increases aggregation. Increased aggregation results in lower differences of relative humidity of the soil to the sky. This lowers the boundary layer, pulling the clouds down making it easier for smaller drops to hit the ground.

At about 3 years, either by quorum sensing or by soil moisture response to atmospheric pressure gradients, trees on the edges of paddocks or within paddocks sense clouds and release both bacteria and terpenes to nucleate and aggregate rain drops.

Typically, 15 to 20 minutes after the trees’ leaves become lighter (release terpenes) the first light rain falls and 15- 20 minutes or so after the first rain, intense rain falls caused by the energy released through the evaporation of the first rain in cooling the land.

In some parts of Australia, this pulling down of rain is known colloquially as square clouds water. It is only created once the sponge is fully developed and deep, approximately 3 years after beginning regenerative practice to build aggregation.

Fixing soil aggregation is only one part of the necessary activities to rehydrate the landscape.

On Friday 6 March, on Hydroterra’s Friday Seminar, I’ll be elaborating on these activities with examples from around the world. I welcome and encourage you to join us at noon, Australian EST to let science explain why talking trees aren’t nuts!

And if you want to read FDR's full letter to the State Governors, you can find it here: https://www.presidency.ucsb.edu/documents/letter-all-state-governors-uniform-soil-conservation-law)

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