Food.
Livestock.
Colonies.
Manure.
Haber-Bosch process.
Industrialised Agriculture.
Green revolution.
Feed burgeoning population.
There is an notion that prior to the industrial revolution,
the lives of ordinary people living in rural communities, in Europe were simpler, better, and happier.
This is a myth.
These people endured rather than enjoyed their lifestyle.
Farming was a hard and dirty business.
The only reason they lived like that, was because there was no alternative.
A typical season of cultivation which prevailed over 100s of years, was by rotating crops.
Typically one field will be used to grow a cereal, another would be used to grow vegetables,
while the third would be kept fallow, or used as pasture to feed animals.
Most people kept some livestock, to provide additional food.
Animals also could be traded to provide extra income.
Animals played an essential role in regenerating the land.
They grazed freely, and spread their manure over fallow fields.
The diet of peasants was low in fat and high in fibre.
The daily staples were made up of cereals, like wheat, oats, barley, etc,.
Medieval diets lacked vitamins A, C and D.
They were not high in calories.
The seasonal fluctuations in the availability of food was enormous.
There were long periods of poor nutrition, and some times border line starving.
The medieval world in Europe was a hungry one.
Winter season was usually very tough.
Storing enough food to feed the family and animals during winter, was a stressful task.
Whenever possible livestock herds were cut down, through sale or slaughter.
Meat would be salt cured and stored in barrels to preserve it.
Most people anyway did not have much meat.
In winter cattle was fed a subsistence diet, which cause milk production to dry up.
In winter people had a thin gruel of vegetables like onions, leek, colewort and lentils.
It was an extremely precarious existence.
Endemic malnutrition caused the people of medieval Europe to decrease in body size.
Stunting is an evolutionary response to food shortage.
Stunting can happen if the mother is malnourished during pregnancy,
or the individual is malnourished during adolescence.
Once stunting has occurred it cannot be reversed later in life, by better nutrition.
Average heights of men fell from 173 centimetres in the 11th century to 165 centimetres in the 17th century.
In comparison the average height is 175 centimetres today.
Limiting body size also affected life expectancy and cognitive development.
The European medieval population were smaller, less intelligent and shorter lived.
When shortages became more profound, famines happened.
Famines happened whenever demand for food exceeds agricultural yields.
Famines can last for many years.
In medieval times the infrastructure to transport food over long distances was not there.
Famines played a role in limiting the maximum sustainable population.
Agricultural techniques which evolved in Britain between 1500 and 1900,
succeeded in overcoming food scarcity.
A medieval farmer could increase output by reducing the amount of fallow land.
Fallow land could be as much as 30%.
However the fallow stage was essential for the soil to recover its fertility.
Improvements in drainage, soil management, and better understanding of crops let to the development,
of a much more effective four field rotation system.
Turnip and clover was added into the mix to help restore vital nutrients.
All these helped to eliminate the need to leave the land fallow for a year.
To manage land properly animals and agriculture had to be separated.
Domestic livestock could eat the crops grown for humans.
Keeping the animals under control, required hiring shepherds.
Animals were kept in small enclosures which required less looking after.
After the black death, labour costs began to soar.
This increased the motivation to enclose animals.
Enclosure meant that animals could be selectively bred, through several generations,
to develop desirable features like woolliness, meatiness, or milkiness.
Coal started to fuel the burgeoning metal work industry.
Agriculture became increasingly mechanised.
Advanced iron ploughs, and inventions like the seed drill,
reduced the amount of labour required to til the land.
These developments meant that productivity could be maximised,
by reducing the amount of labour.
The unemployed started migrating to towns and cities, to work in the emerging factories.
Agriculture, industry and scientific innovation was closely interrelated.
Without surplus food the industrial and scientific revolutions could not have taken place.
The printing press made mass communication possible.
Technology spread rapidly through the increasingly literate population of Europe.
Each revolution supported and relied on other revolution.
Farming, technology and commerce are inextricably interlinked.
The population in Britain increased four fold between 1800 and 1900.
This meant four times more food, and all the other needs of day to day living.
Fortunately there was enough energy to drive this growth.
There was still a ceiling on how much domestic farms could supply,
by efficient use of land, crop rotation and mechanisation.
In the industrial world population was growing 10 times faster than food production.
The answer was to find more land for agriculture.
The additional land was provided by colonies in North America, Africa, and Asia.
19th century Britain were fed by the empire.
British dominions had vast tracts of arable and pastoral land.
The surplus food from British dominions was sold to other industrialised nations.
Industrialised nations became dependent on imported food.
By the early 20th century world population was around 2 billion.
Agricultural shortages was still a salient issue.
Without additional colonies to exploit, the only way to increase food production,
was to improve the fertility of the soil.
The management of tilth fecundity was not new.
It has been going on since the neolithic ages.
The understanding of how and why fertilisers work, came about only in the mid 19th century.
Plants grow by feeding on 13 essential nutrients present in the soil.
When a plant dies, and is left to decay, these nutrients are returned to Earth.
If the plant is removed before that, nutrients are also removed.
Land will recover if left fallow.
But this can take years.
To speed the process up fertilisers containing 1 or more of the missing essential nutrients,
can be added to the soil.
The most important nutrients, are the three macronutrients,
nitrogen, phosphorus and potassium.
These are present in animal waste.
80 to 90% of the nutrients originally in the soil, is present in animal waste.
Spreading this manure on the fields, is one way of returning the nutrients to the soil.
The benefit was spreading manure, was known in the medieval period.
Animal manure was a dispersed resource, and recovery was a logistical problem.
Human manure also contains the macronutrients, nitrogen, phosphorus and potassium.
It was widely used between the 15th and 19th century.
These organic fertilisers have major disadvantages.
They contain relatively low concentration of the required nutrients.
It is not economical to transport them too far.
20 tonnes of cow dung is required to provide 100 kg of nitrogen fertiliser.
This is enough for 1 acre or .4 hectare of land.
The majority of nitrogen is locked up in organic substances, which can take years to break down.
Despite these drawbacks, this was the only fertiliser available till the 20th century.
A major breakthrough occurred in 1827,
when nitrogen was identified as an essential nutrient, by Lieberg.
He is known as the father of the fertiliser industry.
He discovered that plant growth is limited, not by the total amount of nutrients,
but by the level of the scarcest nutrient.
In practice the limiting nutrient is usually nitrogen.
Lieberg deduced that adding nitrogen to the soil, in the form of ammonia,
would have a profound effect on fertility.
In early 1900s ground bones was used along with manure.
By 1830 these bones were dissolved in sulphuric acid and mixed with sodium nitrate,
to produce liquid ammonium nitrate.
This was an effective fertiliser.
Sodium nitrate which had very little use before, now had great demand.
Chile had vast natural deposits of this compound.
This was the world’s largest naturally occurring source of nitrate.
By the first decade of the 20th century, the world wide demand for nitrogen based fertiliser,
exceeded the amount that could be supplied naturally.
The amount exported from Chile was not enough.
Another German scientist called Fritz Haber, managed to create ammonia artificially.
Haber’s ammonia synthesis proved to be of fundamental importance for the modern world.
The expansion of the world’s population from 1.6 billion in 1900 to 7.3 billion today,
would not have been possible without it.
Haber was a brilliant scientist, who was awarded the Nobel prize in 1918.
Unfortunately Haber was also involved with the German government,
in developing chemical weapons to kill people.
For this, he is known as the father of chemical warfare.
Haber invented the process of synthesising ammonia,
by the direct reaction of hydrogen and nitrogen, in the presence of a metal catalyst.
Another scientist called Carl Bosch helped to develop,
an industrial scale production process, for ammonia.
It won Bosch a Nobel prize.
The process is now called the Haber-Bosch process.
By 1916 ammonia was being produced in commercial quantities.
Bosch’s industrial process strips out hydrogen from methane or natural gas.
It uses carbon monoxide to do so.
A lot of energy consumed in liberating the highly reactive hydrogen,
and converting methane into carbon dioxide.
The converter reacts one nitrogen molecule with three hydrogen molecules,
to make two ammonia molecules.
This is done at a pressure of 200 atmospheres, or 3000 psi, and temperatures of 500 degree centigrade.
Better and better fertilisers were invented, in the form of ammonium sulphate,
nitro chalk and ammonium phosphate.
Till today the Haber-Bosch process is vital to the fertiliser industry.
The ammonia it produces sustains 2/3rds of the world’s population.
More than half the protein in our bodies, was originally fixed by the Haber-Bosch process.
The process is however energy expensive.
It accounts for 3% of the global consumption of natural gas.
The use of ammonium nitrate fertiliser increased soil productivity.
It allowed the amount of arable land to be expanded.
It also allowed for cultivation to become more intensive.
But there was no significant impact on crop yields.
The harvest rarely exceeded 2 tonnes per hectare.
Increasing yields required new species of plants,
that could take advantage of the now abundant supplies of nitrogen,
by converting them into seeds and roots,
rather than stalks and leaves.
During the 1950’s plant breeding went through a revolution.
It left the farm and entered the laboratory.
Through out the 20th century agriculture became more industrialised.
It incorporated developments in fertiliser, plant and machinery, irrigation,
and bespoke pesticides and herbicides.
However the most important development was the emergence of a variety of high yield cultivars.
The scientist Norman Borlaug is credited with leading the research, that resulted in the green revolution.
Borlaug studied genetics and plant breeding.
He also had the humanitarian aim of feeding the hungry people in the world.
He was involved in developing, high yield, short straw, disease resistant varieties of wheat.
The key breakthrough was the development of crop trades,
that would not have been favoured by natural selection.
He found that low stature wheat and other crops produce high yields.
They were able to do so by allocating more resources to the grain,
at the expense of height and competitive ability.
The hybrid wheat that Borlaug developed, was able to increase the crop yield,
from .5 tonnes per hectare to 4 tonnes per hectare.
Later a new cultivar of rice was developed called the IR8.
This new variety required the use of fertilisers and pesticides, but produced substantially higher yields.
Yields increased from 3.7 tonnes per hectare to 7.7 tonnes per hectare in Philppines.
India also adapted to the IR8 hybrid.
It yielded 5 tonnes per hectare without fertiliser, and 10 tonnes per hectare in optimal conditions.
With increase in yields there was a dramatic drop in the price of rice.
Norman Borlaug got the Nobel prize for peace in 1970.
By 2009 the production of cereals tripled in developing countries.
Yields have also increased through developments in irrigation, fertiliser and seed design.
The human body has changed more in the past 100 years, then in the last 50000 years.
Adults today are 50% heavier and 10cm taller.
For the first time height wise we reached the size of our hunter gatherer ancestors.
Better nutrition played a large role in this.
The green revolution was responsible in feeding the burgeoning population of the last century.
The downside to all this success is that energy required to produce crops increased significantly.
Today, more net energy than ever before is needed to grow each kilo of food.
The high yield varieties rely on chemical fertilisers, which are energy intensive to produce.
Production of pesticides and herbicides also required high energy.
Modern agriculture is now entirely dependent on the petrochemical industry.
The negative implication of this intimate relationship is very clear.
When we runout of oil, we will also run out of food.
The green revolution supports the huge population we have today.
But it comes with the significant caveat.
Agricultural crops are wholly dependent on our intervention for survival.
Unfortunately the benefit of the green revolution has not been uniform across the world.
The per capita consumption of food has come down by 20% in Africa.
We hardly hear discussions about global food security.
It is difficult to visualise food shortage amidst plenty.
The concerns of modern agriculture is mainly environmental.
It is the reliance on chemicals and the loss of bio diversity, that concerns us.
The wide spread use of herbicides and pesticides, can have profound negative impacts on flora and fauna.
However the concerns are focused on the health impact on humans.
Large scale mono culture with heavy fertiliser use, and no crop rotation leads to loss of bio-diversity.
The pressure to create more farm land, has led to the destruction of millions of hectares of rainforest.
The new high yield varieties of crops are tolerant of soil conditions which prevented agriculture before.
This has resulted in the loss of steppe and savannah, which is being converted into farmland.
This form of habitat loss is the primary cause of degradation of global biodiversity.
The consultive group of international agricultural research maintains over 650 thousand samples of crops,
forage, and agroforestry resources in seed and gene banks, so that they are not permanently lost.
The Haber-Bosch fixation of nitrogen along with Borlaug’s green revolution,
enables us to feed the burgeoning population of the world.
Modern fertiliser methods can feed 35 to 45 people per hectare.
Compared to this the best organic methods can feed only 12 to 15 persons per hectare.
In theory the most intensively farmed land can feed 50 people per hectare.
To feed the growing population of the world, there needs to be a 50% increase in food production, by 2030.
This needs to be done with less water, less fertiliser, less herbicides and pesticides.
Agriculture will have to become more sustainable and less energy intensive.
Part of the solution will be to develop crops which are more resistant to diseases and pests,
and efficient use of water and fertiliser.
We need to increase the efficiency of photosynthesis.
One way to do this is genetically modifying plants to improve the intrinsic photosynthetic capability of plants.
Food security depends on efficient provision of nutrients to soil.
Human waste is an under utilised resource, which could play a major role as a fertiliser.
Some groups of microbes play a central role in controlling the flux of nutrients from the soil into plants.
In natural eco systems microscopic fungi, supply the plant partner with mineral nutrients.
They act as an extension to the root network.
This nutrient subsidy is exchanged for carbon fixed by photosynthesis of the plant.
Understanding this symbiotic relationship of plant and fungi, could enable us to create new varieties of plants.
A combination of these solutions could help us produce enough food for the expected population.