Plants – Architects of the Soil

“We know more about the movement of celestial bodies than we do about the soil underfoot” – Leonardo Da Vinci 

The most mysterious of things occur out of sight and in the most apparently benign of places. What many of us see as simply dirt is in fact a creative universe constantly pulsating life in existence. I’m reluctant to quote the Bible, Christianity has left a sour taste in most rational mouths. I’m sure I’ll regret this…… Genesis 2:7 “And the Lord God formed man from the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul”. The latin root of the word Human? Humus!!!! (of the earth). And Humus is the magical black gold that is the basis of soil fertility. Hmmmm maybe the bible isn’t complete and utter bullshit after all…. or maybe it is. 

So we are made from the earth, and once expired we shall return back to the earth. Seems legit. 

Other than us strange apes, what other forms of life emerge from the soil? Literally all terrestrial life must give thanks to this lowly dirt. The most obvious of all lifeforms arising from soil are the plants; sprouting from seeds in the earth and sending adventurous roots throughout the soil. They are very much “of the earth”. Maybe they are more ‘human’ than us?

Time for an age old conundrum…. substituting out the chicken and egg.
What came first: The plant or the soil? 

Conventional soil science will lean towards the idea that in order to have a healthy plant, you must first have a healthy soil. But what if in actual fact it is plants that have created soil? Firstly, we must understand that soil, and in particular healthy soil, is more than. just mineral dirt. It contains countless bacteria, protozoa, nematodes, fungi, worms and plant roots. Along with the final stage of organic matter decomposition: humus. A complex web of life. Really it is this web of life that turns dirt into soil and thus gives rise to higher forms of life. 

So, it’s all these soil organisms that really make soil so soil-ish. And in order for these organisms to live, they need two essential building blocks: Nitrogen and Carbon. Nitrogen makes up 80% of the Earth’s atmosphere and numerous ‘nitrogen-fixing’ bacteria have evolved to sequester and bring nitrogen into the organic realm. Even the nitrogen-fixing legumes have just cozied up to some N-fixing bacteria. However Carbon, the building block of all life forms, can only be sequestered by living, photosynthesising plants. It is this carbon, captured by plants, that bacteria, fungi and all other higher life forms need for energy and for building bodies. 

Most plants exude over half of all the carbon they capture out into their root zones. Wait, what??? They willingly dispose of over half of that precious sugar they have so cleverly captured? Yep, the nectar of all life is sent out into this lump of dirt that surrounds their roots. Plants aren’t unwilling victims forced to spend their days exposed to the elements. They are actually far-sighted geniuses that understand the value in investing where the most returns can be gained. The soil. By sending vast amounts of carbon into the soil, bacteria and fungi are fed and kept happy. Bacteria thrive in the rich sugars and organic acids exuded by plants, their populations flourish, they fix nitrogen and turn it into amino acids like there’s no tomorrow. Once they die, those amino acids become available for plant consumption. Just go down the mind-boggling rabbit hole of rhizophagy…. you’ll see that plants aren’t peace-loving vegans, they’re actually bacteria hungry carnivores (https://johnkempf.com/an-introduction-to-rhizophagy/). And then we have the mycorrhizal fungi which form symbiotic relationships with plant roots, trading sugars for minerals that they have extracted from the dirt. Sugar: the currency of life. 

Soil microorganisms are able to breakdown complex carbon molecules left over by higher life forms into stable humus. This ‘new’ black gold is able to increase a soil’s water and nutrient holding capacity. This in turn allows plants to increase their photosynthetic activity, capture more carbon and keep the wheel turning.

Plants are not helpless bystanders at the mercy of the elements. They are constantly building soil, improving their environment and forming reciprocal relationships with other organisms. They are really the architects of the soil. Everything we do in the vineyard and kitchen garden is in keeping with this idea. We use nutrients to optimise plant photosynthesis, provide an accommodating environment for microbes to thrive and then step back and let the plants do what they do best: build soil.