Throughout history, in times of war, famine, or ecosystem destruction, people have taken to eating earth. In the first century medical treatise De Medicina, the deliberate consumption of earth, soil, or clay – otherwise known as geophagia – was said to be accompanied by skin irritation, anaemia, and devastating “pains in the head.”1 Whether geophagia was the cause or outcome of these symptoms is ambiguous. The contemporary Diagnostic and Statistical Manual of Mental Disorders (5th ed.) classifies geophagia a form of “pica,” a compulsive desire to eat “non-nutritive matter.” We know that humans cannot synthesise vitamin B12, but can absorb it from bacteria that live in soil. The same goes for calcium, copper, iron, zinc, and other “non-foods” essential to immune function and cell reproduction. These metals are especially important for children and pregnant women, the two groups in which geophagia is most commonly observed. Could the morbid remedy of ingesting the planet suggest a hidden hunger that is currently going unseen and unfed?

One of the most fertile soils on Earth is known by the name Chernozem, the Ukrainian for “black earth.” It is found stretching across the Eurasian wheat belt – including eastern Ukraine, where it is at present being desecrated by heavy weaponry – on the Great Plains of North America, and in a somewhat altered form in the Amazon Basin, where it is known as terra preta de índio or “Indians’ black earth.”

The origins of terra preta have been heavily debated, with theories ranging from Andean volcanic ash fall to ancient peat bogs. In fact, this nutrient-rich, ultra-resilient soil was formed when indigenous Amazonians threw bones, manure, crockery shards, and other household waste onto kitchen middens, cultivating patches of ground in the low-fertility forest floor (ancient forests suck nutrients up to the canopy layer). They enhanced the soil with charcoal to prevent leaching, fostering the growth of productive microorganisms in a synthetic ecology that has remained in place for generations.

Soil is a highly accelerated cycling and re-organisation of chemicals and infrastructure formed from the living and dying of bacteria, microbes, insects, worms, nematodes, symphylids, and countless other diverse beasts. This loop whereby death is folded into new life calls to mind the figure of the golem, a rerun of the Genesis myth where it is man, not God, who spawns an uncontrollable intelligence out of the massa confusa of dirt. It’s the in-house mascot of cyberneticians, gene editors, and machine learning specialists – the golem system runs, after all, by placing a spell made from numbers in its mouth. Today however, the creation of a capricious being from symbolically neglected matter resonates most loudly with soil science – a discipline concerned with the material substrate on which the entirety of global food production relies.2

Soil is a living organism that needs to be fed. It has a technical skeleton, an immune system, competing workers, and a fussy diet. The biotech startup AgBiome maps environmental soil samples from four continents to sequence and compare traits in plants and microorganisms that could fend off pests in agriculture, reducing the need for surplus applications. The absence of bone infections in the skeletal remains of ancient Nubian populations is believed to stem from antibiotic exposure from the soil – and an information arms race is under way to discover other “proprietary microbes” for use in industry.3 Although many farmers remain skeptical of this “biological” approach, it is a far easier sell for end users (and investors) who march in lock-step (or ahead of) soil ecologists and microbiologists seeking to unlock secrets underfoot.

The food system is riddled with golems: shuffling in your kitchen waste, mulching unharvested crops, but above all in the Earth’s soil, roughly half of which has been degraded by poor management. Perhaps the golem could be a guide: out of a magical understanding of nature in which human language acts on objects, into one in which all objects are transformed via mind-independent manipulations of matter to be studied and harnessed towards beneficial ends. Terra preta, one of the best performing soils we have, is anthropogenic.4 It is a collaborative synthesis that benefits both humans and the land they tend, a planetary paradigm that emerged from the kitchen, an everyday laboratory where experimentation and invention is performed.

  1. Aulus Cornelius Celsus’s De Medicina dates back to the first century CE, but archeologists have uncovered calcium-enriched clay patties alongside the remains of Homo Habilis, an ancient African hominid who roamed between 2.31 million years ago to 1.65 million years ago. Clay, stone, and dirt tablets were consumed as both remedy and hunger suppressant in ancient Mesopotamia and the practice continues today. Kaolinite is eaten with pepper and cardamom in western Africa for its anti-diarrhetic effects. In the 1960s, NASA gave astronauts calcium montmorillonite clay from California to counter bone wastage. Luvos Heilerde, a granulate composite of sand, clay, and silt, is a mainstay of bathroom medicine cabinets in Germany.
  2. In Regenesis (Allen Lane, 2022), journalist George Monbiot notes that while we have international treaties that structure aviation, investments, and intellectual property, there is no multilateral agreement that even makes recommendations for soil health. There is also no existing soil ecology institute anywhere on Earth.
  3. Evidence for the benefits of antibiotic substances received through soil applied to skin, in traditional medicine, or attached to food as part of diet continues to mount, but so too does the discovery of valuable microorganisms since 1900. Bleomycin, originally identified in soil, is used as chemotherapy for common cancers including Hodgkin’s lymphoma. Amphotericin B was recovered from a strain of bacteria on the Orinoco riverbed in Venezuela, and is a WHO essential medicine used to treat serious fungal infections. We co-evolved with and continue to host a constellatio of microbes whose silent hunger can negatively impact our physiology in the form of allergies, inflammatory diseases, and depression. There is robust science to back up clichés about letting your kids play in dirt. Being outside on your knees as an adult you do internal gardening while planting flowers. This is eating too.
  4. Lombardo, U., Arroyo-Kalin, M., Schmidt, M. et al. “Evidence confirms an anthropic origin of Amazonian Dark Earths” in Nature Communications 13, 3444 (2022).

Reference Material No: 2023.04.919(B)
Object: Book
Location: RA0h0m0s|Dec-0°0′0″
Properties: 24949 Words, Limited Edition Hard Cover, Vacuum Sealed
Publisher: Medialab-Matadero, Madrid ISBN: 978-84-09-44877-7