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The Plough

16 Apr 2021
Soilprobioti

When the history of human interaction with our planet is written by wiser iterations of ourselves in some hopefully intact future, there will be many sub-headings that say: ‘Oops, shouldn’t have done that.’ Apart from everything that would have led to the climate crisis, one of them will be our love affair with the plough.

When World War 2 ended, huge factories tooled for tanks, guns and explosives shifted into tractors, harvesters and fertilisers, sparking the Green Revolution.

Across the planet, rivers were blocked by dams and sluiced into irrigation. High-yielding varieties of wheat, rice and maize were planted on vast monocrop fields to supply burgeoning populations.

It worked. At the end of the war there were 2.5 billion humans, by 1970 there were four billion and we are now at 7.5. In terms of numbers, the plough/fertiliser relationship was a resounding success.

It was soon apparent, however, that the fields didn’t do well unless they were artificially supplied with nitrogen, phosphorus and potassium (NPP). Nobody enquired too closely why the plants couldn’t find this themselves, as they had for millions of years.

The sea is full of natural NPP, but when plants first emerged on land a few billion years ago the land had very little. Plants developed a symbiosis between those that converted sunlight into carbohydrates and those that dug essential elements out of sand and rocks. They fed each other.

Today beneath trees and grassland is the dark, invisible support system of the mycorrhizae. They are fine, hair-like filaments of fungus that attach themselves to roots and create vast, intricate underground nutrient supply networks, the importance of which mycologists are just beginning to understand.

Mycorrhizal networks act as inter-tree chemical internets and food chains. They can span entire continents, partnering 95% of all plants... except for plants on our fields for two reasons. Our chemical load kills mycorrhizae and, because they mostly live within the top 20cm of soil, ploughing destroys them. THAT’S why we have to fertilise.

It’s perfectly possible to plant crops by lightly scarifying the soil surface, leaving the mycorrhizae intact. If we did that we wouldn’t need fertiliser. Or ploughs. Or have dead rivers.

But imagine agricorps like Monsanto, Bayer, Dow Chemicals or John Deer permitting the shutdown of global financial opportunity? Not gonna happen.