Tag Archives: agriculture

Was agriculture the greatest blunder in human history?

The Conversation

File 20171018 32345 1rwww1s.jpg?ixlib=rb 1.1
Rice farmers near Siem Reap, Cambodia. Darren Curnoe, Author provided

Darren Curnoe, UNSW

Twelve thousand years ago everybody lived as hunters and gatherers. But by 5,000 years ago most people lived as farmers.

This brief period marked the biggest shift ever in human history with unparalleled changes in diet, culture and technology, as well as social, economic and political organisation, and even the patterns of disease people suffered.

While there were upsides and downsides to the invention of agriculture, was it the greatest blunder in human history? Three decades ago Jarred Diamond thought so, but was he right?

Agriculture developed worldwide within a single and narrow window of time: between about 12,000 and 5,000 years ago. But as it happens it wasn’t invented just once but actually originated at least seven times, and perhaps 11 times, and quite independently, as far as we know.

Farming was invented in places like the Fertile Crescent of the Middle East, the Yangzi and Yellow River Basins of China, the New Guinea highlands, in the Eastern USA, Central Mexico and South America, and in sub-Saharan Africa.

And while its impacts were tremendous for people living in places like the Middle East or China, its impacts would have been very different for the early farmers of New Guinea.

The reasons why people took up farming in the first place remain elusive, but dramatic changes in the planet’s climate during the last Ice Age — from around 20,000 years ago until 11,600 years ago — seem to have played a major role in its beginnings.

The invention of agriculture thousands of years ago led to the domestication of today’s major food crops like wheat, rice, barley, millet and maize, legumes like lentils and beans, sweet potato and taro, and animals like sheep, cattle, goats, pigs, alpacas and chickens.

It also dramatically increased the human carrying capacity of the planet. But in the process the environment was dramatically transformed. What started as modest clearings gave way to fields, with forests felled and vast tracts of land turned over to growing crops and raising animals.

In most places the health of early farmers was much poorer than their hunter-gatherer ancestors because of the narrower range of foods they consumed alongside of widespread dietary deficiencies.

At archaeological sites like Abu Hereyra in Syria, for example, the changes in diet accompanying the move away from hunting and gathering are clearly recorded. The diet of Abu Hereyra’s occupants dropped from more than 150 wild plants consumed as hunter-gatherers to just a handful of crops as farmers.

In the Americas, where maize was domesticated and heavily relied upon as a staple crop, iron absorption was consequently low and dramatically increased the incidence of anaemia. While a rice based diet, the main staple of early farmers in southern China, was deficient in protein and inhibited vitamin A absorption.

There was a sudden increase in the number of human settlements signalling a marked shift in population. While maternal and infant mortality increased, female fertility rose with farming, the fuel in the engine of population growth.

The planet had supported roughly 8 million people when we were only hunter-gatherers. But the population exploded with the invention of agriculture climbing to 100 million people by 5,000 years ago, and reaching 7 billion people today.

People began to build settlements covering more than ten hectares – the size of ten rugby fields – which were permanently occupied. Early towns housed up to ten thousand people within rectangular stone houses with doors on their roofs at archaeological sites like Çatalhöyük in Turkey.

By way of comparison, traditional hunting and gathering communities were small, perhaps up to 50 or 60 people.

Crowded conditions in these new settlements, human waste, animal handling and pest species attracted to them led to increased illness and the rapid spread of infectious disease.

Today, around 75% of infectious diseases suffered by humans are zoonoses, ones obtained from or more often shared with domestic animals. Some common examples include influenza, the common cold, various parasites like tapeworms and highly infectious diseases that decimated millions of people in the past such as bubonic plague, tuberculosis, typhoid and measles.

In response, natural selection dramatically sculpted the genome of these early farmers. The genes for immunity are over-represented in terms of the evidence for natural selection and most of the changes can be timed to the adoption of farming. And geneticists suggest that 85% of the disease-causing gene variants among contemporary populations arose alongside the rise and spread of agriculture.

In the past, humans could only tolerate lactose during childhood, but with the domestication of dairy cows natural selection provided northern European farmers and pastoralist populations in Africa and West Asia the lactase gene. It’s almost completely absent elsewhere in the world and it allowed adults to tolerate lactose for the first time.

Starch consumption is also feature of agricultural societies and some hunter-gatherers living in arid environments. The amylase genes, which increase people’s ability to digest starch in their diet, were also subject to strong natural selection and increased dramatically in number with the advent of farming.

Another surprising change seen in the skeletons of early farmers is a smaller skull especially the bones of the face. Palaeolithic hunter-gatherers had larger skulls due to their more mobile and active lifestyle including a diet which required much more chewing.

Smaller faces affected oral health because human teeth didn’t reduce proportionately to the smaller jaw, so dental crowding ensued. This led to increased dental disease along with extra cavities from a starchy diet.

Living in densely populated villages and towns created for the first time in human history private living spaces where people no longer shared their food or possessions with their community.

These changes dramatically shaped people’s attitudes to material goods and wealth. Prestige items became highly sought after as hallmarks of power. And with larger populations came growing social and economic complexity and inequality and, naturally, increasing warfare.

Inequalities of wealth and status cemented the rise of hierarchical societies — first chiefdoms then hereditary lineages which ruled over the rapidly growing human settlements.

Eventually they expanded to form large cities, and then empires, with vast areas of land taken by force with armies under the control of emperors or kings and queens.

This inherited power was the foundation of the ‘great’ civilisations that developed across the ancient world and into the modern era with its colonial legacies that are still very much with us today.

The ConversationNo doubt the bad well and truly outweighs all the good that came from the invention of farming all those millenia ago. Jarred Diamond was right, the invention of agriculture was without doubt the biggest blunder in human history. But we’re stuck with it, and with so many mouths to feed today we have to make it work better than ever. For the future of humankind and the planet.

Darren Curnoe, Associate Professor and Chief Investigator, ARC Centre of Excellence for Australian Biodiversity and Heritage, University of New South Wales, UNSW

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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The Medieval Agrarian Economy

by Tim Harding

This striking image depicts the three main classes of medieval society – the clergy, the knights and the peasantry.[1]  Tellingly, the cleric and the knight are shown talking to each other; but the peasant is excluded from the conversation.  Even though the peasants comprised over 90% of the population, they were in many ways marginalized socially and economically.  So who were these peasants and what was their daily life like?

striking

Source of image: Wikimedia Commons

The term ‘peasant’ essentially means a traditional farmer of the Middle Ages, although in everyday language it has come to mean a lower class agricultural labourer.  In the Central Middle Ages, that is the period from 1000 to 1300CE, European peasants were divided into four classes according to their legal status and their relationship to the land they farmed.  These classes were slave, serf, free tenant or land owner.  The first two classes were usually much poorer than the second two.

There were several factors that influenced the lives of peasants during this period.  The reciprocal benefits of agricultural labour and warrior protection gave rise to closely settled manorial and feudal communities.[2]  More land was brought under cultivation by the communal clearing of forests, draining of swamps and the building of levees or dykes.[3]

The invention of a heavier wheeled plow enabled deeper cultivation of soils, including the burying of green manure from fallow land and also stubble from previous crops.  The deeper furrows also protected seed from wind and birds.[4]

plough

Source of image: Wikimedia Commons

There was also a period of warmer temperatures, milder winters and higher rainfall at this time, resulting in longer growing seasons.[5]  Another important factor was the replacement of the Roman two-field rotation system by a more efficient three-field system, enabling two-thirds of the land to be under cultivation at any one time, instead of only half the land.  This image shows the three cropping fields (West, South and East) of a typical rural community, with the remaining quarter devoted to pasture, the Manor house and Church.[6]

rural community

Source of image: Bennett, Judith M., Medieval Europe – A Short History
(New York: McGraw-Hill, 2011). p. 142.

Interestingly, the typical length of a plow-strip was 220 yards, called a furlong (a word still used in horse racing today).  The width of a plow-strip was a rod, and a rectangle of 4 rods by one furlong became an acre.[7] (Four rods later became a ‘chain’ of 22 yards, so an acre was an area one furlong by one chain).

The resulting increases in agricultural yields raised farm production above subsistence levels for the first time in centuries.   These surpluses not enabled not only trade, but also the storage of produce such as oats for the feeding of horses.  This in turn enabled the replacement of plow-pulling oxen by horses that required less pasture that could be reallocated to cropping.  Horses also moved and turned faster than oxen, resulting in even more efficiencies.[8]

Crop yields for wheat improved to an estimated four times the quantity of grain sown.  Typically, one quarter of the yield was reserved for the next planting, one or two quarters went to the lord of the manor as rent, and the remainder was either consumed as bread or beer, stored for the winter or sold at local markets.[9]

Few peasants could afford meat to eat – they mainly lived on bread, beer and vegetables grown by women and children in small cottage gardens, plus eggs from chickens and milk from cows and goats.  Those living in coastal areas also ate fish. [10]

 Bibliography

Backman, Clifford R., The Worlds of Medieval Europe (Oxford: Oxford University Press, 2015).

Bennett, Judith M., Medieval Europe – A Short History (New York: McGraw-Hill, 2011).

Endnotes

[1] Bennett, Judith M., Medieval Europe – A Short History (New York: McGraw-Hill, 2011) p.135.

[2] Backman, Clifford R., The Worlds of Medieval Europe (Oxford: Oxford University Press, 2015) p.215

[3] Bennett, p.140.

[4] Backman, p.218.

[5] Bennett, p.139.

[6] Bennett, p.140-142.

[7] Backman, p.217.

[8] Backman, p.218.

[9] Backman, p.219.

[10] Backman, p.220.

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The rabbits of Christmas past: a present that backfired for Australia

The Conversation

By Andrew Bengsen, University of New England

On Christmas Day 1859, the Victoria Acclimatisation Society released 24 rabbits for hunting, to help settlers feel more at home.

Given the millions of dollars in damage to agricultural productivity that ensued, as well as the impacts on biodiversity as the rabbits bred and spread to cover 70% of the continent, this could be seen as Australia’s worst Christmas present.

Now, given our current climate change commitments, controlling rabbits could be “Santa’s little helper” in reducing greenhouse gas emissions.

In 2007, Australia committed to reduce its greenhouse gas emissions to at least 5% below 2000 levels, by the year 2020. This commitment remains central to our climate change policy, and we should expect greater emissions reduction targets in future if we comply with the international target of limiting global warming to plus 2 deg C.

Storing carbon in the land

There’s been plenty of talk of planting more trees. But case studies and evaluations of government programs such as Bushcare show that this is an expensive way to re-vegetate.

Instead, many people now recognise there are better ways to manage carbon across large areas. Livestock grazing and fire (such as “savanna burning”) are often cited as important factors to manage and enhance carbon storage in plants and soils across vast areas.

Some significant gains might also be achieved by reducing the damage caused by some of our most serious pest animals.

Eating us out of house, home and carbon

Rabbits are well known for their ability to strip grasslands bare and destroy the seedlings of woody shrubs and trees. Even in low numbers, rabbits can completely prevent some important woody species from regenerating.

Mulga woodlands, for example, cover vast tracts of inland Australia, and mulga trees are likely to be a very important carbon store in these areas. However, rabbit numbers as low as one animal per hectare can effectively stop the replacement of old trees by destroying seedlings.

Distribution of rabbits (orange, left) and mulga woodlands (green, right) across Australia. Rabbit data from West 2008.

Recently, Tarnya Cox and I reviewed the potential benefits of controlling rabbits and other invasive herbivores for reducing Australia’s greenhouse gas emissions. We unearthed a multitude of similar stories about the extensive damage that rabbits can cause to vegetation and ecosystem function, and how that may affect the ability of these systems to capture and store carbon.

Importantly, much of the damage that rabbits cause to the environment can be reversed.

In many areas, Mulga and other species flourished for the first time in 100 years after rabbit numbers were reduced by up to 95% in the 1990s by rabbit hemorrhagic disease virus (previously known as calicivirus).

Many other studies have also found sudden increases in plant growth after rabbit populations were reduced by disease or intensive conventional control.

A rabbit opportunity

Dying mulga tree and narrow-leaved fuchsia bush in a rangeland area degraded by rabbits and goats. Robert Henzell

The regeneration of Mulga and other woody species over broad areas can make significant contributions to our emissions reduction targets. Mulga and other arid zone acacias are long-lived, grow slowly, and have very dense wood. This means that mature trees can store large amounts of carbon for their size, and keep much of it locked up long after the death of the plant.

Regenerating Mulga woodlands in western Queensland and New South Wales are estimated to capture over half a tonne of carbon dioxide equivalent, per hectare per year, in woody biomass alone. This equates to about four air passengers travelling from Sydney to Brisbane per hectare of mulga woodlands.

Rabbits inhabit most of the 143 million hectares of Australia’s Mulga woodlands. If their populations can be controlled, then there is considerable potential for natural carbon sequestration to help us meet our greenhouse gas reduction targets.

Other invasive herbivores – such as camels and goats – can also reduce vegetation cover and plant carbon storage. However, we already have a solid understanding of the rabbit’s impact on the environment, and they are very widespread which means that their eradication could have large positive impacts.

How to control rabbits

Conventional rabbit control operations – such as warren destruction and poison baiting – can be more cost-effective at regenerating native vegetation, than planting more trees. This would be useful for the large areas of road-side reserves and stock routes which need revegetation. They rival the size of the National Park estate in terms of total area across south-eastern Australia.

These areas would be suitable for conventional rabbit control. Even a small increase in tree density due to rabbit control would help us achieve our greenhouse gas reduction targets. Rabbit control is often required to allow tree plantings to establish and flourish.

A rabbit feeds on a planted tree surrounded by a tree guard, despite an apparent abundance of green vegetation outside the tree guard. Mark Hillier, Invasive Animals Cooperative Research Centre, Author provided

Of course, there are many challenges in reducing the damage caused by rabbits, and improve our chances of achieving our greenhouse gas reduction targets. Most importantly, we need accurate estimates of the effect of rabbit control on natural carbon sequestration. We also need a means of monitoring actual carbon sequestration amounts, that complies with the stringent carbon accounting rules of the Kyoto Protocol.

Another major challenge is the declining effectiveness of rabbit hemorrhagic disease. Fortunately, a major cooperative research program is already underway to counter the virus’ diminishing effect, though biological control alone cannot be expected to completely mitigate rabbit impacts.

As we hark back to that fateful Christmas Day in 1859, a future of climate uncertainty, agricultural hardship and the loss of our unique biodiversity, we must be prepared to act on these challenges.

The ConversationThis article was originally published on The Conversation. (Reblogged with permission). Read the original article.

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