The Culture of the Agri
Experimentation has been at the heart of agriculture for millenia.
Introduction
Most of human agriculture’s knowledge until the late 19th century was a product of trial and error, involving disorganized experiments on a nearly global scale. It is easy to get deluded into thinking this was a linear process; however, like most human efforts, it is riddled with failures and dead ends.
Physical evidence of our current crops is well established, dating back around 9,000 years before present (kybp) in the Middle East and South America. Also, we get clear evidence of organized farming around the same time across the globe. However, current genetic studies put the start of domestication processes at 20–13 kybp1. This corresponds to the end of the Pleistocene, our last maximal glacial period. Since then, it has been warmer and, more importantly, stable. These are the ideal conditions for experimenting, testing, and ultimately leading to the crops we got @ 9kybp.
The stable climate allowed for recurring weather patterns for thousands of years, allowing for a generation of people to pick up on the pattern allowing it to be culturally integrated. However, most of the practices were not necessarily regenerative. However, they thrived when regenerative processes occurred by chance.
For example, due to yearly flooding, the fertile crescent and Egyptians relied on regular silt deposits for their regenerative practices. However, slash-and-burn techniques were common; clearing forest land would boost nutrients for a few years due to the start on rich forest soil.
Most of our current knowledge regarding agriculture practices before written records relies on direct and indirect archaeological evidence. The case of indirect, for example, crop rotation, irrigation, and fertilization, involves careful analysis of each layer of sediment along with analyzing surviving seeds associated with a field and time and studying its chemical components. For example, in this study, researchers studied isotopes of Carbon and Nitrogen to determine whether Neolithic and Bronze Age fields were exposed to water, manuring, and crop rotation.
As mentioned earlier, the indirect study of genetic variation can provide approximate dates for the onset of events associated with the domestication of plants, animals, and even humans. Most direct evidence involves technology; for example, we have concrete evidence of plowing from approximately 6,000 years before present (ybp) in central Europe and Akkadian depictions on seals from approximately 4,000 ybp. Around the Mediterranean, rotation and cover crop practices were known by 3000 kybp and were likely already well established before that.
However, nothing beats having written sources describing techniques, context, consequences, and specific recipes. The oldest written instruction that has survived comes from a Greek poem from the Homeric age, “Work and Days.” While not very instructive, it gives common tips on figuring out when to start sowing, build a plow, and harvest. The writing appears to date to approximately 3000 ybp. However, it does not mention crop rotation or soil fertilization; and overall not very detailed, one shouldn’t expect much; after all it’s a poem, not an almanac.
“When the Pleiades, daughters of Atlas, are rising, begin your harvest, and your ploughing when they are going to set. Forty nights and days they are hidden and appear again as the year moves round, when first you sharpen your sickle. This is the law of the plains, and of those who live near the sea, and who inhabit rich country, the glens and dingles far from the tossing sea,--strip to sow and strip to plough and strip to reap, if you wish to get in all Demeter’s fruits in due season, and that each kind may grow in its season.” — Work and Days
For reference, the Pleiades rises around mid-to-late May for European latitudes. The poems show the role astronomy played in the daily life of early farmers, setting their schedules and activities throughout the year. This pattern will be consistent in future writings, providing a universal language for growers from dispersed cultures.
While not many writings survived, the ones that did referenced earlier writers from throughout the Mediterranean. The most famous of the reference writings was Mago the Carthaginian. Mago the Carthaginian was described as having written 28 volumes in the Phoenician language, primarily on agriculture and animal husbandry, whose practices were well known throughout the Iron Age.
His works were translated and summarized into Greek after the Third Punic War, and later into Latin. However, since we have lost most of Mago’s writing, and what remains is paraphrased by other later ancient writers, it is hard to know exactly what was described and when. But they do include references to earlier writing from Carthage and details fertilizing with dung and green manure.
Regarding the records we do have, particularly Roman ones, they start showing up by 2500 kybp.
Roman Sources
In the upcoming parts, we will focus on the preserved written accounts of the aggregated Roman knowledge of soil, nutrients, and plants. We understand Roman knowledge of agriculture from Marcus Porcius Cato (234 — 149 BCE), Marcus Terentius Varro (116 — 27 BCE), Callumela (7 CE- 70AD), and Pliny the Elder ( 23/24 — 79 CE). There are later writings, but we will focus on the first two.
They all compiled the accumulated knowledge at their respective times, and are detailed enough yet summarize previous writings without clear attribution. They primarily include anecdotal and quantitative information on crops and farm management. In the case of Pliny the Elder, his agricultural-related writings are found in ‘Nature Historis’, an overall compilation of the natural history of all contemporary knowledge, with sections on wheat, legumes, and other plants. I have yet to read it carefully enough to form an opinion and will rely on secondary sources.
For historical context, for those of you who have yet to listen to Mike Ducan’s The History of Rome podcast2, Cato lived through the tumultuous Punic wars, dying right at the onset of the Third. The end of the Punic War marks the sacking of Carthage, a pivotal event in which the contents of its libraries were destroyed, distributed, or taken in by the Romans, significantly impacting what knowledge endured, and how.
Varro, a polymath who lived through Ceaser’s rise and subsequent fall, provides a more ‘scientific` view of agriculture. His works nonetheless encompass several rituals and ceremonies for the gods of agriculture, highlighting the pragmatic and artistic views that characterized ancient Roman agricultural practices. And Collumella’s publication was during the rise of the Flavian Dynasty. Pliny lived during a time of relative peace and is famous for his compilation of natural history, and additionally having died trying to rescue a friend from the catastrophe at Pompeii.
As mentioned, I will provide an overview of the first two.
Cato the Elder’s De Agri Cultura
Marcus Porcius Cato, also known as Cato the Elder, was a Roman statesman, orator, and writer. The same Cato instigated the Third Punic War by ending every speech, no matter the subject, with: “Carthago delenda est” (Carthage must be destroyed).
Cato is best known for his work De Agri Cultura (On the Culture of Fields), the oldest surviving complete work of Latin prose. Given the pagan rituals inscribed, the fact that it survived complete tells us just how important agriculture was. His writing style is relatively informal but incredibly detailed, almost like a letter to a friend with detailed instructions. The work focuses on what has worked for him.
He was known to be rather strict about morality or the Roman idea of morality, which is evident in his first paragraph. Here, he compares four trades: traders, moneylenders, thieves, and farmers. According to him, traders and money lenders make the most money. However, trading is too risky for him, while money-lending is less honorable. He then shows this belief goes back to their ancestors, who punished crimes by thieves with double what they’ve stolen and moneylenders with four times! Further, it gives insight into the value attributed to farmers.
“when [our ancestors] would praise a worthy man, their praise took this form: ‘good husbandman, good farmer’” — Cato the Elder
In De Agri Cultura, Cato provides practical advice and instructions on various aspects of agriculture, farm management, animal husbandry, and several recipes associated with its outputs. It starts with finding and buying a good farm, advice that is valid today for any real estate affair:
“When you are thinking of acquiring a farm, keep in mind these points: that you be not over-eager in buying nor spare your pains in examining, and that you consider it not sufficient to go over it once. However often you go, a good piece of land will please you more at each visit. Notice how the neighbours keep up their places; if the district is good, they should be well kept. Go in and keep your eyes open,…” —Cato the Elder
However, we will focus on plant nutrition and soil preparation, for which he offered the following insights.
It should have a good climate, not subject to storms; the soil should be good, and naturally strong. If possible, it should lie at the foot of a mountain and face south — Cato
This initial generic advice clearly demonstrates the need to maximize sun exposure in a northern hemisphere region while protecting the land from high winds. The advice gets further detailed; much of the advice associated with soil type is only clarified by using references in the later documents by Pliny and Collumena. e.g., what is meant by rich or soil.
This rule should be observed as to what you should plant in what places:— Grain should be sown in heavy, rich, treeless soil; and if this sort of soil is subject to fogs it should preferably be sown with rape, turnips, millet, and panic-grass. In heavy, warm soil plant olives — those for pickling, the long variety, the Sallentine, the orcites, the posea, the Sergian, the Colminian, the waxy-white; choose especially the varieties which are commonly agreed to be the best for these districts. — Cato
First and foremost, Cato stresses matching the soil and climate to the crop. Cato then stressed the importance of maintaining soil fertility through manure. I understand this is our first direct source for using manure in the field, particularly green manure. However, this knowledge is of course much older and has a scientific foundation through isotope studies. He recommended maintaining two manure pits, one fresh and one rotten, and utilizing manure from sheep, goats, and other organic materials, such as ashes and crop residues.
He advocated using green manures, which involved plowing leguminous crops like lupins and broad beans into the soil to enrich it. Going as far as suggesting rotating crops to prevent soil depletion and maintaining soil productivity. He recommended alternating cereals with legumes, except chickpeas, and leaving fields fallow for a period. What’s interesting is that he mentioned this is because they harvest the chickpeas with the roots still attached.
We know that legumes’ nitrogen-fixing properties are due to root nodules, which provide an ideal environment for nitrogen-fixing bacteria. If the roots are left after harvest, more bacteria dissipated into the soil, increasing natural nitrogen-fixing bacteria in the free soil for the next season. While they had little understanding of the underlying mechanism, they seemed to be aware that it was a phenomenon due to the roots of legumes.
Another curious point from his writings is that he provided information on using amurca to stop or reduce spoilage during preparation and storage of other crops. Amurca being a byproduct of olive oil production, a dark-colored residue that settled from unfiltered olive oil. Given the scale of Roman olive oil production it was then easily available and cheap. This seems to be a bit of “ancient lost knowledge” regarding amurca’s herbicide and insecticide properties. However, most relevant cases of lost knowledge are likely due to a behavior similar to antibiotic cycling; for example, as microbial resistance builds up, some ancient recipes are dismissed as they become less potent and are eventually wholly ignored. I will try looking for more references to Amurca in future postings, but if you know any info, feel free to comment or DM me.
Next
Next time, I will review the writings of Varro, who was, in fact, the main reason I started this post. His writings are often cited as the beginning of germ theory, or at least a precursor to the knowledge of that time. Yet, it is based on a single passing sentence in selecting a place for a farm!
Robin G. Allaby, et all “Emerging evidence of plant domestication as a landscape-level process,” https://www.sciencedirect.com/science/article/pii/S0169534721003050
https://www.perseus.tufts.edu/hopper/text?doc=plin.+nat.+toc
https://www.agriculturalmuseums.org/2023/08/19/the-vallus-a-2000-year-old-gallo-roman-harvesting-machine/
https://thehistoryofrome.typepad.com/